The effect of muscle type and freezing on the evolution of physico-chemical properties during processing of South African biltong and its final textural properties
- Authors: Ngwendu, Nwabisa
- Date: 2020
- Subjects: Biltong Meat -- Quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12128 , vital:39154
- Description: The study investigated the effect of muscle type and freezing on evaluation of mass transfer during processing physico-chemical of South African biltong and its textural properties. In the first experimental phase of this study, mass transfers, physico-chemical and textural properties (hardness, cohesiveness, springiness, and chewiness) of commercially produced biltong from biceps femoris (BF) and semitendinosus (ST) (n=9) were measured. Biltong was dried at 30oC and 40% relative humidity until it had lost 50% of its initial weight. The initial moisture content, water activity (Aw) of BF muscles (74.3% and 0.992) were significantly lower compared those of ST muscles (75.4% and 0.994%). The fat content of BF (2.3%) muscles was higher (P<0.05) than in ST muscles (1.7%). The salt, weight and water gain for the BF muscle were 2.3%, -2.6% and -7.0% respectively and were significantly higher than those of ST muscles which were 2.1, -0.4 and -4.0, respectively. After drying, the moisture content, Aw, and pH were lower in BF (42.2, 0.886 and 5.29) than those of ST muscles (45.1, 0.911 and 5.42). The salt content was higher (P<0.05) in BF muscle than in ST. Among textural properties, hardness was significantly higher in biltong from the BF (233.0N), while the springiness was significantly lower compared to the ST muscle (178.2N). Therefore, it was concluded that the use of different muscles results in variation of biltong physicochemical characteristics. The second experiment investigated the effect of freezing and muscle type on mass transfers, lipid oxidation, physico-chemical and textural properties of biltong. In this experiment, the iii ST muscles were replaced with semimembranosus (SM) muscles. A total of 12 beef muscles were used, with six BF and six SM muscles frozen in a blast freezer at -40 oC till they reached -20oC; then they were transferred to -20oC for 14 days. The thawing loss for the BF and ST muscles was 1.3 and 2.4% respectively, but there were no significant (P>0.05) differences. The protein and salt content were significantly higher in frozen-thawed (24.3 and 0.13%) muscles than in fresh muscle (20.2 and 0.08%); whereas the fat content and pH were lower (P<0.05) in frozen-thawed (5.36) compared to fresh muscles (5.51). Between muscles, the moisture, salt content, and pH were higher in BF muscles than in SM muscles (73.2, 0.12% and 5.49). Aw was affected by the interaction between freezing and muscle type, with frozenthawed SM having lower Aw (0.990). During salting, salt, weight and water gain did not show any differences (P<0.05). There were no major significant differences after salting. There were lower TBARS and pH in frozen-thawed (1.5mgMDA/kg and 5.15) muscles than in fresh muscles (3.3mgMDA/kg and 5.19) as well as in SM muscles (1.8mgMDA/kg and 5.16) than in BF muscles (3.0mgMDA/kg and 5.19). The moisture was significantly lower in frozen-thawed SM (68.1%) than in fresh SM, BF and frozen-thawed BF (69.3,70.5 and 71.7%) after salting. On the final product, the interaction between muscle type and freezing affected the moisture content, TBARS, chewiness and the springiness of biltong, with the biltong from fresh SM (39.8%) having significantly lower moisture content compared frozenthawed BF and ST muscles as well fresh BF muscles (42.8% in average). The TBARS were higher in biltong from fresh BF muscles (5.1mgMDA/kg) compared to other muscles. Furthermore, the chewiness and springiness were higher (P<0.05) in biltong produced from SM frozen-thawed muscles (327.7N and 1.5). The WBSF was higher in biltong from the BF muscles (108.8N) than in the biltong from SM (80.1) but it was not affected by the freezing effect (P>0.05). Freezing did not show any major differences in biltong. iv The third experiment was conducted to determine the effect of freezing African buffalo carcasses on weight loss during salting, physico-chemical and textural properties of biltong. Five muscles (ST, SM, BF, LTL, and RF) were randomly selected from 30 carcasses (15 frozen-thawed and 15 fresh), cut along the grain, traditionally salted and dried at 26oC till they lost 45-50% of their initial weight. The salting weight loss was higher in frozen-thawed muscles (-1.45%) than in fresh muscles (-0.89%). The freezing treatment affected the physico-chemical properties of the biltong. The biltong produced from frozen-thawed muscles showed significantly higher protein and ash (47.6 and 7.6%) compared to fresh (43.9 and 7.1); whereas the moisture, fat, pH and Aw were lower (43.7, 2.1, 0.870 and 5.30, respectively) compared to those of biltong from fresh muscles (45.5%, 2.9%, 0.890 and 5.38). The moisture, pH and fat content were further affected by muscle type. The interactive effect was observed in salt content, with RF frozen-thawed showing higher salt content (8.2%) compared to all other muscles. The hardness and WBSF were significantly higher (P<0.05) in biltong frozen-thawed (204.1N and 135.0N) than in fresh muscles (146.2N and 113.1N). Moreover, the chewiness and springiness were affected (P<0.05) by muscle type, with RF muscle having higher springiness 0.89 and chewiness 171.1N than all the other muscles. Therefore, it can be concluded that freezing buffalo carcasses significantly influenced the quality characteristics of biltong. The fourth experiment studied the effect of drying methods on physico-chemical properties of traditional biltong produced from African buffalo muscles. The BF and SM muscles were randomly selected from 15 fresh carcasses, cut into strips, salted and divided into two batches per muscle. The first batch of each muscle type was dried in the ambient-air drier at 22oC average and the second batch in the cabinet drier at 26 oC till 45-50% weight loss. No differences (P>0.05) were observed in salting weight loss between the drying method and muscle type. The protein content was significantly higher in SM (46%) muscles compared to v BF (43%) but there was no effect (P>0.05) caused by the drying method. The interactions between the muscle type and drying method affected the fat content, with biltong from airdried BF muscles having significant lower (2.1%) fat content. There were no significant differences in other physico-chemical properties of biltong, with moisture content, salt, ash content, Aw and pH being 45.0%, 5.13%, 44.8%, 7.3%, 2.7%, 0.885 and 5.61 on average, respectively. Overall, the findings of the study show that freezing does have a significant effect on the final quality of biltong. However, it can be concluded that a significant effect on the physico-chemical properties of biltong depends on the changes of mass transfers during salting and drying.
- Full Text:
- Date Issued: 2020
- Authors: Ngwendu, Nwabisa
- Date: 2020
- Subjects: Biltong Meat -- Quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12128 , vital:39154
- Description: The study investigated the effect of muscle type and freezing on evaluation of mass transfer during processing physico-chemical of South African biltong and its textural properties. In the first experimental phase of this study, mass transfers, physico-chemical and textural properties (hardness, cohesiveness, springiness, and chewiness) of commercially produced biltong from biceps femoris (BF) and semitendinosus (ST) (n=9) were measured. Biltong was dried at 30oC and 40% relative humidity until it had lost 50% of its initial weight. The initial moisture content, water activity (Aw) of BF muscles (74.3% and 0.992) were significantly lower compared those of ST muscles (75.4% and 0.994%). The fat content of BF (2.3%) muscles was higher (P<0.05) than in ST muscles (1.7%). The salt, weight and water gain for the BF muscle were 2.3%, -2.6% and -7.0% respectively and were significantly higher than those of ST muscles which were 2.1, -0.4 and -4.0, respectively. After drying, the moisture content, Aw, and pH were lower in BF (42.2, 0.886 and 5.29) than those of ST muscles (45.1, 0.911 and 5.42). The salt content was higher (P<0.05) in BF muscle than in ST. Among textural properties, hardness was significantly higher in biltong from the BF (233.0N), while the springiness was significantly lower compared to the ST muscle (178.2N). Therefore, it was concluded that the use of different muscles results in variation of biltong physicochemical characteristics. The second experiment investigated the effect of freezing and muscle type on mass transfers, lipid oxidation, physico-chemical and textural properties of biltong. In this experiment, the iii ST muscles were replaced with semimembranosus (SM) muscles. A total of 12 beef muscles were used, with six BF and six SM muscles frozen in a blast freezer at -40 oC till they reached -20oC; then they were transferred to -20oC for 14 days. The thawing loss for the BF and ST muscles was 1.3 and 2.4% respectively, but there were no significant (P>0.05) differences. The protein and salt content were significantly higher in frozen-thawed (24.3 and 0.13%) muscles than in fresh muscle (20.2 and 0.08%); whereas the fat content and pH were lower (P<0.05) in frozen-thawed (5.36) compared to fresh muscles (5.51). Between muscles, the moisture, salt content, and pH were higher in BF muscles than in SM muscles (73.2, 0.12% and 5.49). Aw was affected by the interaction between freezing and muscle type, with frozenthawed SM having lower Aw (0.990). During salting, salt, weight and water gain did not show any differences (P<0.05). There were no major significant differences after salting. There were lower TBARS and pH in frozen-thawed (1.5mgMDA/kg and 5.15) muscles than in fresh muscles (3.3mgMDA/kg and 5.19) as well as in SM muscles (1.8mgMDA/kg and 5.16) than in BF muscles (3.0mgMDA/kg and 5.19). The moisture was significantly lower in frozen-thawed SM (68.1%) than in fresh SM, BF and frozen-thawed BF (69.3,70.5 and 71.7%) after salting. On the final product, the interaction between muscle type and freezing affected the moisture content, TBARS, chewiness and the springiness of biltong, with the biltong from fresh SM (39.8%) having significantly lower moisture content compared frozenthawed BF and ST muscles as well fresh BF muscles (42.8% in average). The TBARS were higher in biltong from fresh BF muscles (5.1mgMDA/kg) compared to other muscles. Furthermore, the chewiness and springiness were higher (P<0.05) in biltong produced from SM frozen-thawed muscles (327.7N and 1.5). The WBSF was higher in biltong from the BF muscles (108.8N) than in the biltong from SM (80.1) but it was not affected by the freezing effect (P>0.05). Freezing did not show any major differences in biltong. iv The third experiment was conducted to determine the effect of freezing African buffalo carcasses on weight loss during salting, physico-chemical and textural properties of biltong. Five muscles (ST, SM, BF, LTL, and RF) were randomly selected from 30 carcasses (15 frozen-thawed and 15 fresh), cut along the grain, traditionally salted and dried at 26oC till they lost 45-50% of their initial weight. The salting weight loss was higher in frozen-thawed muscles (-1.45%) than in fresh muscles (-0.89%). The freezing treatment affected the physico-chemical properties of the biltong. The biltong produced from frozen-thawed muscles showed significantly higher protein and ash (47.6 and 7.6%) compared to fresh (43.9 and 7.1); whereas the moisture, fat, pH and Aw were lower (43.7, 2.1, 0.870 and 5.30, respectively) compared to those of biltong from fresh muscles (45.5%, 2.9%, 0.890 and 5.38). The moisture, pH and fat content were further affected by muscle type. The interactive effect was observed in salt content, with RF frozen-thawed showing higher salt content (8.2%) compared to all other muscles. The hardness and WBSF were significantly higher (P<0.05) in biltong frozen-thawed (204.1N and 135.0N) than in fresh muscles (146.2N and 113.1N). Moreover, the chewiness and springiness were affected (P<0.05) by muscle type, with RF muscle having higher springiness 0.89 and chewiness 171.1N than all the other muscles. Therefore, it can be concluded that freezing buffalo carcasses significantly influenced the quality characteristics of biltong. The fourth experiment studied the effect of drying methods on physico-chemical properties of traditional biltong produced from African buffalo muscles. The BF and SM muscles were randomly selected from 15 fresh carcasses, cut into strips, salted and divided into two batches per muscle. The first batch of each muscle type was dried in the ambient-air drier at 22oC average and the second batch in the cabinet drier at 26 oC till 45-50% weight loss. No differences (P>0.05) were observed in salting weight loss between the drying method and muscle type. The protein content was significantly higher in SM (46%) muscles compared to v BF (43%) but there was no effect (P>0.05) caused by the drying method. The interactions between the muscle type and drying method affected the fat content, with biltong from airdried BF muscles having significant lower (2.1%) fat content. There were no significant differences in other physico-chemical properties of biltong, with moisture content, salt, ash content, Aw and pH being 45.0%, 5.13%, 44.8%, 7.3%, 2.7%, 0.885 and 5.61 on average, respectively. Overall, the findings of the study show that freezing does have a significant effect on the final quality of biltong. However, it can be concluded that a significant effect on the physico-chemical properties of biltong depends on the changes of mass transfers during salting and drying.
- Full Text:
- Date Issued: 2020
Effect of dietary Mucuna pruriens seed meal on the serum lipid profile and bone quality traits of broiler chickens
- Authors: Hempe, Chumani
- Date: 2019
- Subjects: Legumes Lipoproteins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17213 , vital:40866
- Description: This study aimed at evaluating the effects of heated Mucuna pruriens seed meal on the blood serum lipid profile and bone quality parameters of broiler chickens. A total of 120 day-old unsexed Cobb 500 broiler chicks were randomly allocated for the 4 treatment diets (T1, T2, T3 and T4) containing 0, 10, 15, and 20% heated Mucuna pruriens seed meal. The birds were reared on wood shaving floor pens for 35 days. Birds were humanely slaughtered by severing the jugular vein using a sharp knife. Blood was collected into a tube, centrifuge and analyzed for a lipid profile analysis (total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), triglycerides (TCD) as well as aspartate transaminase (AST) and alanine transaminase (ALT)) by enzymatic diagnostic kits (Diasys diagnostic kits). Both drumsticks severed using a sharp knife. After boiling in the water at 100°C for 10 mins the tibia bones were taken, air-dried for 96 hrs at room temperature and measured for weights. Bone length, strength, moisture and ash content as well as morphology were measured. The blood lipid profile of birds fed T1 was high (P < 0.05) for all the parameters measured, while T3 had the lowest (P < 0.05) profile. T2 and T4 had the same profile. ALT was found to be highest (P < 0.05) for T4 (5.27 ± 0.207/L) and lowest (P < 0.05) for T2 (4.67 ± 0.333/L) while AST was highest (P < 0.05) for T2 (320.13 ± 28.851/L) and lowest (P < 0.05) for T3 (208.47 ± 10.059/L). Treatment diet 3 (T3) was observed decreased bone quality among all diets; with the lowest (P < 0.05) bone strength (188.55 ± 12.039N), bone length (8.59 ± 0.131cm) and morphology (1.69 ± 0.058). Mucuna pruriens seed meal inclusion in broiler diets reduces blood serum lipids and 20% inclusion levels have no adverse effects on the bone quality attributes
- Full Text:
- Date Issued: 2019
- Authors: Hempe, Chumani
- Date: 2019
- Subjects: Legumes Lipoproteins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17213 , vital:40866
- Description: This study aimed at evaluating the effects of heated Mucuna pruriens seed meal on the blood serum lipid profile and bone quality parameters of broiler chickens. A total of 120 day-old unsexed Cobb 500 broiler chicks were randomly allocated for the 4 treatment diets (T1, T2, T3 and T4) containing 0, 10, 15, and 20% heated Mucuna pruriens seed meal. The birds were reared on wood shaving floor pens for 35 days. Birds were humanely slaughtered by severing the jugular vein using a sharp knife. Blood was collected into a tube, centrifuge and analyzed for a lipid profile analysis (total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), triglycerides (TCD) as well as aspartate transaminase (AST) and alanine transaminase (ALT)) by enzymatic diagnostic kits (Diasys diagnostic kits). Both drumsticks severed using a sharp knife. After boiling in the water at 100°C for 10 mins the tibia bones were taken, air-dried for 96 hrs at room temperature and measured for weights. Bone length, strength, moisture and ash content as well as morphology were measured. The blood lipid profile of birds fed T1 was high (P < 0.05) for all the parameters measured, while T3 had the lowest (P < 0.05) profile. T2 and T4 had the same profile. ALT was found to be highest (P < 0.05) for T4 (5.27 ± 0.207/L) and lowest (P < 0.05) for T2 (4.67 ± 0.333/L) while AST was highest (P < 0.05) for T2 (320.13 ± 28.851/L) and lowest (P < 0.05) for T3 (208.47 ± 10.059/L). Treatment diet 3 (T3) was observed decreased bone quality among all diets; with the lowest (P < 0.05) bone strength (188.55 ± 12.039N), bone length (8.59 ± 0.131cm) and morphology (1.69 ± 0.058). Mucuna pruriens seed meal inclusion in broiler diets reduces blood serum lipids and 20% inclusion levels have no adverse effects on the bone quality attributes
- Full Text:
- Date Issued: 2019
Muscle nanostructure and physicochemical characteristics of South African A and AB mutton classes
- Authors: Mdikili, Zizipho
- Date: 2019
- Subjects: Meat -- Quality -- South Africa
- Language: English
- Type: Thesis , Masters , (MSc) (Animal Science)
- Identifier: http://hdl.handle.net/10353/12005 , vital:39126
- Description: Significant variations exist in quality of red meat due to the effect of various intrinsic and extrinsic factors. Research has been conducted in early 1990s to prove that carcasses from A and AB classes differ in meat quality due to age variation. This led to a conclusion that the two should be separated in the South African Red meat Classification System (SARCS). However, an interesting debate arose from a carcass classification workshop that A and AB meat classes have the same quality and thus must be integrated into one class in the carcass classification system. In addition, as much as it can be debated that these classes have the same quality, it is also possible that slight differences exist between the two since they are from different age groups. The current study was therefore developed and two trials were conducted to evaluate the impact of age differences on physicochemical attributes and muscle nanostructure of A and AB classes in sheep. In the first trial a total of ninety (n=90) Dorper sheep of the same sex but different age groups slaughtered at a high throughput abattoir in the Eastern Cape province were used to evaluate meat ultimate pH (pH24), colour (L* , a* , b* , H* , C* ), thawing loss (TL%), cooking loss (CL%) and tenderness (Warner Bratzler Shear Force - WBSF) of A and AB classes, whereas, on the second trial forty (n=40) Dorper sheep were used to evaluate muscle nanostructure and its relationship with tenderness. Meat samples were harvested from the Muscularis longissimuss thoracis et lumborum (LTL) for v meat quality and nanostructure measurements. The results showed significant variations (P<0.05) between the two classes for lean a* , H* and CL%. Significant differences (P<0.01) were observed in pH24, TL% and WBSF between A and AB classes. However, there were no significant differences (P>0.05) observed in meat L*, b* and C * . Ultimate pH was negatively correlated with thawing loss and some colorimetric attributes of lamb such as lightness, yellowness and hue angle. Moreover, tenderness was positively correlated with cooking and thawing losses. Significant differences were not (P>0.05) observed in sarcomere length, myofibrilar diameter and shear force between A and AB classes. Both sarcomere length and myofibrilar diameter were not correlated (P>0.05) with meat tenderness. These results suggest that A and AB classes are the same in nanostructure and that muscle nanostructure of these two classes is not related to meat tenderness. It was concluded that meat from sheep carcasses falling under the A and AB classes in the South African classification system vary greatly in physicochemical quality. Moreover, sheep carcasses from A and AB classes have the same sarcomere lengths and hence, they do not differ in meat tenderness (WBSF). However, when these classes were observed under a microscope, slight differences were noted in sarcomere lengths and myofibrilar diameters, which led to a conclusion that the two should remain as separated classes because their combination would result in the expansion of the non-uniformity of red meat tenderness. Therefore, A and AB classes should not be combined in the South African classification system. Further research is, however, recommended to evaluate the influence of other factors that were not examined in the current study.
- Full Text:
- Date Issued: 2019
- Authors: Mdikili, Zizipho
- Date: 2019
- Subjects: Meat -- Quality -- South Africa
- Language: English
- Type: Thesis , Masters , (MSc) (Animal Science)
- Identifier: http://hdl.handle.net/10353/12005 , vital:39126
- Description: Significant variations exist in quality of red meat due to the effect of various intrinsic and extrinsic factors. Research has been conducted in early 1990s to prove that carcasses from A and AB classes differ in meat quality due to age variation. This led to a conclusion that the two should be separated in the South African Red meat Classification System (SARCS). However, an interesting debate arose from a carcass classification workshop that A and AB meat classes have the same quality and thus must be integrated into one class in the carcass classification system. In addition, as much as it can be debated that these classes have the same quality, it is also possible that slight differences exist between the two since they are from different age groups. The current study was therefore developed and two trials were conducted to evaluate the impact of age differences on physicochemical attributes and muscle nanostructure of A and AB classes in sheep. In the first trial a total of ninety (n=90) Dorper sheep of the same sex but different age groups slaughtered at a high throughput abattoir in the Eastern Cape province were used to evaluate meat ultimate pH (pH24), colour (L* , a* , b* , H* , C* ), thawing loss (TL%), cooking loss (CL%) and tenderness (Warner Bratzler Shear Force - WBSF) of A and AB classes, whereas, on the second trial forty (n=40) Dorper sheep were used to evaluate muscle nanostructure and its relationship with tenderness. Meat samples were harvested from the Muscularis longissimuss thoracis et lumborum (LTL) for v meat quality and nanostructure measurements. The results showed significant variations (P<0.05) between the two classes for lean a* , H* and CL%. Significant differences (P<0.01) were observed in pH24, TL% and WBSF between A and AB classes. However, there were no significant differences (P>0.05) observed in meat L*, b* and C * . Ultimate pH was negatively correlated with thawing loss and some colorimetric attributes of lamb such as lightness, yellowness and hue angle. Moreover, tenderness was positively correlated with cooking and thawing losses. Significant differences were not (P>0.05) observed in sarcomere length, myofibrilar diameter and shear force between A and AB classes. Both sarcomere length and myofibrilar diameter were not correlated (P>0.05) with meat tenderness. These results suggest that A and AB classes are the same in nanostructure and that muscle nanostructure of these two classes is not related to meat tenderness. It was concluded that meat from sheep carcasses falling under the A and AB classes in the South African classification system vary greatly in physicochemical quality. Moreover, sheep carcasses from A and AB classes have the same sarcomere lengths and hence, they do not differ in meat tenderness (WBSF). However, when these classes were observed under a microscope, slight differences were noted in sarcomere lengths and myofibrilar diameters, which led to a conclusion that the two should remain as separated classes because their combination would result in the expansion of the non-uniformity of red meat tenderness. Therefore, A and AB classes should not be combined in the South African classification system. Further research is, however, recommended to evaluate the influence of other factors that were not examined in the current study.
- Full Text:
- Date Issued: 2019
Muscle nanostructure, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus
- Authors: Soji, Zimkhitha
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15264 , vital:40332
- Description: The main objective of this study was to determine the effect of muscle nanostructure on tenderness, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus. Fifty two A-class steers (n=52) of five breeds (Bonsmara (n=19), Beef master (n=7), Hereford (n=9) and Simbra (n=17)) typically processed in different South African feedlots were studied. The animals were humanely slaughtered at an abattoir following the commercial standard procedures. Fat colour measurements (CIE b*) were taken at the P8 site on hot carcasses at the abattoir. Carcass mass (warm and cold) was recorded at the slaughter line before chilling (warm) and after chilling (cold) while pH0 and temperature were measured at 45 minutes post-mortem on the Longissimus thoracis et lumborum (LTL) muscle. Thereafter, a 20 g subsection of the LTL muscle on the left side of each carcass was sampled for muscle nanostructure analysis. At 24 hours post-slaughter, ultimate pH (pH24) was measured, further subsections of the LTL muscle (20 g) were harvested for further muscle nanostructure analysis and 2.5 kg of the LTL muscle was also harvested for analysis of tenderness, fatty acids and sensory evaluation. The muscle nanostructure (myofibril diameter (MYD), myofibril spacing (MYS), muscle fibre diameter (MFD), muscle fibre spacing (MFS) and sarcomere length (SL)) was analysed using the scanning electron microscope (SEM) while tenderness was measured using Warner Bratzler Shear Force after 45mins, 24hrs, 3 and 7 days aging period at -20 ºC refrigerator temperature. Some proximate fractions (total extractable intramuscular fat (Fat %), Fat Free Dry matter (FFDM %) and Moisture content) and fatty acid profile were measured using extracted fat and fatty acid indices (desaturase index, atherogenicity index) were calculated. Lastly a Check-All-That-Apply visual profiling method rated by an 80-member consumer panel was done to assess consumer meat preferences and perceptions of Bonsmara, Hereford and Simbra A2 fresh steaks. At 45mins post-slaughter breed affected (P<0.05) MYD and MYS, while at 24hrs breed affected MFD and MFS only. Early post-mortem pH (pH0) had no effect on the muscle nanostructure and tenderness while ultimate pH (pH24) affected MYD and MYS only. Muscle temperature at 45mins affected (P<0.05) the MYD, MFD and MFS, while 24hrs muscle temperature affected (P<0.05) MYD only. Tenderness was not related to the muscle nanostructure early post-mortem and there was no uniformity on the changes in muscle nanostructure and tenderness from early post-mortem to 24hrs against the multifaceted carcass mass, muscle pH and temperature effects. During ageing, breed affected the MYD and MYS at 45mins, while at 24hrs in addition to the myofibril structure breed also had an effect on muscle fibre bundle characteristics (MFD and MFS). The changes in MYD, MYS and MFS became constant on day 3 while variations in the MFD still progressed. There was no uniformity on the SL pattern during ageing and a very weak linear relationship between tenderness, SL, MFD and MFS was observed. Notably there was also no uniformity on how the muscle texture features; including the surface structure, fibre separation, and the mechanism of muscle contraction and relaxation; changed throughout the ageing period across and within the breeds. Moreover, breed had a significant effect on pentadecyclic acid, total saturated fatty acids (SFA) and docosahexanoic acid. Differences (P<0.05) in SFA, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-6, n-3, fatty acid ratios, and desaturase index were observed among the white, creamy-white and creamy fat colour. The distribution of fatty acid classes was SFA>MUFA>PUFA in descending order of concentrations of mean values (44.19:40.06:15.75, respectively), while the n-6: n-3 ratio was 12:1. In sensory evaluation, consumers indicated how they would prefer to pay premium for meat with guaranteed muscle and fat colour, low fat content, high marbling and tenderness. Consumers observed breed differences (P<0.05) in muscle fibre separation and muscle colour. The overall liking of each attribute was more on moderate bright cherry red lean colour, moderate yellow fat, very abundant marbling and slight separation of muscle fibres. Differences on discrete liking of each attribute among consumers had an effect on the overall liking of each steak with Hereford steaks being more preferred by consumers. It was concluded that meat from beef animals within the same feeding regime has a different fatty acid composition owing to different breed synthetic pathways and feed ingredients and that meat tenderness is not affected by the muscle nanostructure early post-mortem. However, during ageing, meat tenderness is directly linked to breed related myofibril structure changes in particular the myofibril diameter, spacing between myofibrils and their interaction; while the muscle texture features, fibre diameter, spacing between muscle fibres and sarcomere length explain the non-uniformity of beef tenderness. Also the organoleptic and health related quality of meat assumed more importance among consumers in sensory evaluation. Thus meat classification systems should include more credence aspects or indicators that support credence quality of meat
- Full Text:
- Date Issued: 2019
- Authors: Soji, Zimkhitha
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15264 , vital:40332
- Description: The main objective of this study was to determine the effect of muscle nanostructure on tenderness, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus. Fifty two A-class steers (n=52) of five breeds (Bonsmara (n=19), Beef master (n=7), Hereford (n=9) and Simbra (n=17)) typically processed in different South African feedlots were studied. The animals were humanely slaughtered at an abattoir following the commercial standard procedures. Fat colour measurements (CIE b*) were taken at the P8 site on hot carcasses at the abattoir. Carcass mass (warm and cold) was recorded at the slaughter line before chilling (warm) and after chilling (cold) while pH0 and temperature were measured at 45 minutes post-mortem on the Longissimus thoracis et lumborum (LTL) muscle. Thereafter, a 20 g subsection of the LTL muscle on the left side of each carcass was sampled for muscle nanostructure analysis. At 24 hours post-slaughter, ultimate pH (pH24) was measured, further subsections of the LTL muscle (20 g) were harvested for further muscle nanostructure analysis and 2.5 kg of the LTL muscle was also harvested for analysis of tenderness, fatty acids and sensory evaluation. The muscle nanostructure (myofibril diameter (MYD), myofibril spacing (MYS), muscle fibre diameter (MFD), muscle fibre spacing (MFS) and sarcomere length (SL)) was analysed using the scanning electron microscope (SEM) while tenderness was measured using Warner Bratzler Shear Force after 45mins, 24hrs, 3 and 7 days aging period at -20 ºC refrigerator temperature. Some proximate fractions (total extractable intramuscular fat (Fat %), Fat Free Dry matter (FFDM %) and Moisture content) and fatty acid profile were measured using extracted fat and fatty acid indices (desaturase index, atherogenicity index) were calculated. Lastly a Check-All-That-Apply visual profiling method rated by an 80-member consumer panel was done to assess consumer meat preferences and perceptions of Bonsmara, Hereford and Simbra A2 fresh steaks. At 45mins post-slaughter breed affected (P<0.05) MYD and MYS, while at 24hrs breed affected MFD and MFS only. Early post-mortem pH (pH0) had no effect on the muscle nanostructure and tenderness while ultimate pH (pH24) affected MYD and MYS only. Muscle temperature at 45mins affected (P<0.05) the MYD, MFD and MFS, while 24hrs muscle temperature affected (P<0.05) MYD only. Tenderness was not related to the muscle nanostructure early post-mortem and there was no uniformity on the changes in muscle nanostructure and tenderness from early post-mortem to 24hrs against the multifaceted carcass mass, muscle pH and temperature effects. During ageing, breed affected the MYD and MYS at 45mins, while at 24hrs in addition to the myofibril structure breed also had an effect on muscle fibre bundle characteristics (MFD and MFS). The changes in MYD, MYS and MFS became constant on day 3 while variations in the MFD still progressed. There was no uniformity on the SL pattern during ageing and a very weak linear relationship between tenderness, SL, MFD and MFS was observed. Notably there was also no uniformity on how the muscle texture features; including the surface structure, fibre separation, and the mechanism of muscle contraction and relaxation; changed throughout the ageing period across and within the breeds. Moreover, breed had a significant effect on pentadecyclic acid, total saturated fatty acids (SFA) and docosahexanoic acid. Differences (P<0.05) in SFA, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-6, n-3, fatty acid ratios, and desaturase index were observed among the white, creamy-white and creamy fat colour. The distribution of fatty acid classes was SFA>MUFA>PUFA in descending order of concentrations of mean values (44.19:40.06:15.75, respectively), while the n-6: n-3 ratio was 12:1. In sensory evaluation, consumers indicated how they would prefer to pay premium for meat with guaranteed muscle and fat colour, low fat content, high marbling and tenderness. Consumers observed breed differences (P<0.05) in muscle fibre separation and muscle colour. The overall liking of each attribute was more on moderate bright cherry red lean colour, moderate yellow fat, very abundant marbling and slight separation of muscle fibres. Differences on discrete liking of each attribute among consumers had an effect on the overall liking of each steak with Hereford steaks being more preferred by consumers. It was concluded that meat from beef animals within the same feeding regime has a different fatty acid composition owing to different breed synthetic pathways and feed ingredients and that meat tenderness is not affected by the muscle nanostructure early post-mortem. However, during ageing, meat tenderness is directly linked to breed related myofibril structure changes in particular the myofibril diameter, spacing between myofibrils and their interaction; while the muscle texture features, fibre diameter, spacing between muscle fibres and sarcomere length explain the non-uniformity of beef tenderness. Also the organoleptic and health related quality of meat assumed more importance among consumers in sensory evaluation. Thus meat classification systems should include more credence aspects or indicators that support credence quality of meat
- Full Text:
- Date Issued: 2019
The effect of replacing antibiotic growth promoters with moringa oleifera leaf powder on growth performance, carcass characteristics, immune organ indices, gut microflora, physicochemical and sensory quality of broiler meat
- Nantapo, Carlos Wyson Tawanda
- Authors: Nantapo, Carlos Wyson Tawanda
- Date: 2018
- Subjects: Moringa oleifera Meat--Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Doctoral , Animal Science
- Identifier: http://hdl.handle.net/10353/17749 , vital:41197
- Description: The objective of the study was to determine the effect of feeding graded levels of Moringa oleifera leaf meal powder (MOLP) on growth performance, carcass characteristics, economic analysis, health status, physicochemical, sensory properties, mineral composition and retention values of meat. A total of 1600 Comb-500 day-old unsexed chicks were allotted to 4 dietary treatment groups, with 4 replicate pens of 100 birds each in a completely randomised design. The dietary treatments were basal diets supplemented with different levels of MOLP as follows; Treatment 1/ control: Basal diet with antibiotic Zinc bacitracin and coccidiostatic Maxiban and no MOLP (0MOLP); Treatment 2: Basal diet included 1percent MOLP (1MOLP); Treatment 3: Basal diet included 3.0 percent MOLP (3MOLP); Treatment 4: Basal diet included 5 percent MOLP (5MOLP). Birds fed basal diets plus 5percent MOLP at starter phase achieved the least FCR 1.53 (P < 0.037), whilst consuming significantly less feed ADFI 47.4 g (P < 0.05). For the entire feeding period, birds fed 5 percent MOLP achieved a favourable FCR of 1.80 among all treatment groups (P < 0.001), but achieved the lowest final live weight (1416 g), carcass weights (1044g) (P < 0.05). Birds fed 0 percent MOLP recorded highest final weight, carcass weight (1339) and the best dressing percentages (76.8percent) (P < 0.05). Abdominal fat levels were reduced by elevating MOLP in diets (P < 0.05). Improvements in proportions of giblets, gizzard, liver and intestine were observed with increase in dietary MOLP. Feed costs increased, while gross and net returns and economic efficiency decreased as dietary MOLP increased. Organ indices of spleen, Bursa of Fabricius and liver were significantly increased by 5percent MOLP in the diet (P < 0.05). Macroscopic lesions scores (P < 0.05) were significantly higher in duodenum, jejunum and ileum of birds in the 1MOLP treatment group on d 28 and d 35. Control and 5MOLP groups recorded the least bloody excreta scores among all treatment groups (P < 0.05). Highest total aerobic bacteria (TAB), E. coli, C. perfringens counts and the lowest lactobacillus spp counts were observed in all intestinal segments in birds in the 1MOLP treatment group. Lower E. coli and C. perfringens but higher lactobacillus spp counts were observed in control and 5MOLP groups (P < 0.05) in the duodenum and jejunum. Increasing MOLP levels in diets led to lower pH and pHu in both breast and leg muscles (P < 0.05). pH was consistently lower in leg muscles than in breast cuts in all treatments and a large decline in post-mortem pH was observed in all muscles of birds in control group. A dietary increase in MOLP level led to a significant increase in L* and b* (P < 0.05) negative correlation between pH and L* (r = -0.463) (P < 0.05) and a weak but significant (P < 0.001) correlation (r = 0.176) between pH and drip loss. Herb flavour (P = 0.0029), appearance (P = 0.0156), aroma (P = 0.0011), colour (P = 0.0375), taste (P = 0.0032) and overall acceptability (P = 0.0192) were improved by grilling, microwave cooking and pan-frying in olive oil. These changes were more pronounced in breast muscle, thus following the trend; microwave > pan-frying in olive oil > grilled samples > boiling for best cooked product based on overall acceptability. Grilling and frying heart muscles resulted in the highest Ca (45.9 mg/kg) and Mg (98.9 mg/kg), whereas boiling led to the lowest Ca (41.1 mg/kg) and Mg (91.4 mg/kg) concentration. The highest concentrations of Fe and Zn these minerals were recorded in grilled (32.7 mg/kg) and fried samples (75.2 mg/kg). Zinc and Fe concentration observed in liver and heart muscles were higher than those found in breast and leg muscle. In conclusion, the results confirm the potential of MOLP for use as an alternative to antibiotics in maintaining broiler health, reducing mortalities and improving carcass characteristics and some meat quality traits.
- Full Text:
- Date Issued: 2018
- Authors: Nantapo, Carlos Wyson Tawanda
- Date: 2018
- Subjects: Moringa oleifera Meat--Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Doctoral , Animal Science
- Identifier: http://hdl.handle.net/10353/17749 , vital:41197
- Description: The objective of the study was to determine the effect of feeding graded levels of Moringa oleifera leaf meal powder (MOLP) on growth performance, carcass characteristics, economic analysis, health status, physicochemical, sensory properties, mineral composition and retention values of meat. A total of 1600 Comb-500 day-old unsexed chicks were allotted to 4 dietary treatment groups, with 4 replicate pens of 100 birds each in a completely randomised design. The dietary treatments were basal diets supplemented with different levels of MOLP as follows; Treatment 1/ control: Basal diet with antibiotic Zinc bacitracin and coccidiostatic Maxiban and no MOLP (0MOLP); Treatment 2: Basal diet included 1percent MOLP (1MOLP); Treatment 3: Basal diet included 3.0 percent MOLP (3MOLP); Treatment 4: Basal diet included 5 percent MOLP (5MOLP). Birds fed basal diets plus 5percent MOLP at starter phase achieved the least FCR 1.53 (P < 0.037), whilst consuming significantly less feed ADFI 47.4 g (P < 0.05). For the entire feeding period, birds fed 5 percent MOLP achieved a favourable FCR of 1.80 among all treatment groups (P < 0.001), but achieved the lowest final live weight (1416 g), carcass weights (1044g) (P < 0.05). Birds fed 0 percent MOLP recorded highest final weight, carcass weight (1339) and the best dressing percentages (76.8percent) (P < 0.05). Abdominal fat levels were reduced by elevating MOLP in diets (P < 0.05). Improvements in proportions of giblets, gizzard, liver and intestine were observed with increase in dietary MOLP. Feed costs increased, while gross and net returns and economic efficiency decreased as dietary MOLP increased. Organ indices of spleen, Bursa of Fabricius and liver were significantly increased by 5percent MOLP in the diet (P < 0.05). Macroscopic lesions scores (P < 0.05) were significantly higher in duodenum, jejunum and ileum of birds in the 1MOLP treatment group on d 28 and d 35. Control and 5MOLP groups recorded the least bloody excreta scores among all treatment groups (P < 0.05). Highest total aerobic bacteria (TAB), E. coli, C. perfringens counts and the lowest lactobacillus spp counts were observed in all intestinal segments in birds in the 1MOLP treatment group. Lower E. coli and C. perfringens but higher lactobacillus spp counts were observed in control and 5MOLP groups (P < 0.05) in the duodenum and jejunum. Increasing MOLP levels in diets led to lower pH and pHu in both breast and leg muscles (P < 0.05). pH was consistently lower in leg muscles than in breast cuts in all treatments and a large decline in post-mortem pH was observed in all muscles of birds in control group. A dietary increase in MOLP level led to a significant increase in L* and b* (P < 0.05) negative correlation between pH and L* (r = -0.463) (P < 0.05) and a weak but significant (P < 0.001) correlation (r = 0.176) between pH and drip loss. Herb flavour (P = 0.0029), appearance (P = 0.0156), aroma (P = 0.0011), colour (P = 0.0375), taste (P = 0.0032) and overall acceptability (P = 0.0192) were improved by grilling, microwave cooking and pan-frying in olive oil. These changes were more pronounced in breast muscle, thus following the trend; microwave > pan-frying in olive oil > grilled samples > boiling for best cooked product based on overall acceptability. Grilling and frying heart muscles resulted in the highest Ca (45.9 mg/kg) and Mg (98.9 mg/kg), whereas boiling led to the lowest Ca (41.1 mg/kg) and Mg (91.4 mg/kg) concentration. The highest concentrations of Fe and Zn these minerals were recorded in grilled (32.7 mg/kg) and fried samples (75.2 mg/kg). Zinc and Fe concentration observed in liver and heart muscles were higher than those found in breast and leg muscle. In conclusion, the results confirm the potential of MOLP for use as an alternative to antibiotics in maintaining broiler health, reducing mortalities and improving carcass characteristics and some meat quality traits.
- Full Text:
- Date Issued: 2018
Characterisation and cryopreservation of semen from indigenous Namaqua Afrikaner sheep breed, in comparison with Dorper and Dohne Merino breeds
- Authors: Letsoalo, Phutiane Thomas
- Date: 2017
- Subjects: Merino sheep Dorper sheep Semen
- Language: English
- Type: Thesis , Masters , Animal Science
- Identifier: http://hdl.handle.net/10353/11707 , vital:39099
- Description: The aim of this study was to characterise and cryopreserve semen of the indigenous Namaqua Afrikaner breed, and to compare it to that of Dorper and Dohne Merino sheep, whose semen is commercially frozen on a large scale. The study was conducted between January and August 2015. September 2013-born Namaqua Afrikaner (12), Dohne Merino (12) and Dorper (9) rams were used in the study. The rams were kept under kraal conditions with adequate shade, and they received a high protein, high energy diet. Originally it was envisaged to collect semen samples using the artificial vagina (AV) method, which proved to be problematic with the Namaqua Afrikaner rams. Semen samples were subsequently collected twice a week by either AV (Dohne Merino and Dorper) or electro-ejaculation (EE; all three breeds). Macroscopic sperm traits were assessed and sperm concentration determined immediately after collection. Each semen sample was diluted with Triladyl® (1:3) and subsequently frozen in liquid nitrogen vapour in straws. Frozen straws were thawed and evaluated at 7, 30 and 90 days after cryopreservation. A droplet (0.5 ml) from each thawed sample was assessed microscopically for post-thaw motility and percentage live sperm. Nigrosin-Eosin smears were prepared of fresh, diluted and frozen-thawed semen samples for determination of percentage live sperm. Data of all the traits were analysed with the GLM and CHI-SQUARE procedures of the SAS statistical package. Breed had a significant effect on ejaculate volume of fresh semen collected either via electro-ejaculation or artificial vagina. Dorper rams (1.37 ± 0.08 ml) and Dohne Merino rams (1.20 ± 0.08 ml) produced ejaculates with higher (P <0.05) semen volume than Namaqua Afrikaner rams (1.09 ± 0.08 ml) when using the EE. With the AV method, Dohne Merino rams (1.46 ± 0.08 ml) produced a higher (P <0.05) ejaculate volume than Dorper rams (1.22 ± 0.08 ml). Motility of the frozen-thawed semen samples was lower than that of the fresh and diluted samples for all breeds and collection methods. Furthermore, motility 3 hours after thawing was also lower than motility assessed immediately after thawing for all breeds and collection methods. Motility of frozen-thawed semen collected with an AV and evaluated at 7, 30 and 90 days after freezing was significantly higher than that collected via EE. Dorper rams had the lowest sperm concentration (1.10 ± 5.29x109 sperm/ml) and the Namaqua rams the highest sperm concentration (1.22 ± 5.20x109 sperm/ml) (P ˂0.05). The AV samples had a higher (P >0.05) sperm concentration (1.20 ± 3.68x109 sperm/ml) than the EE samples (1.11 ± 3.51x109 sperm/ml). The percentage live sperm in the fresh semen samples did not differ among Namaqua Afrikaner (67.76 ± 1.94percent), Dohne Merino (68.59 ± 1.94percent) and Dorper (72.82 ± 1.98percent) rams. The percentage live sperm for all three breeds dropped considerably after freezing to 17.76 ± 2.03percent, 17.86 ± 2.03percent and 22.72 ± 2.07percent respectively. It remained constant for all the breeds from 7 until 90 days after freezing, indicating that length of storage should not have an effect on percentage live sperm for semen collected via AV or EE. Percentage live sperm of the frozen-thawed semen of the Namaqua rams was lower than that of the Dorper rams, indicating that the Namaqua semen collected via EE did not freeze as well as that of the Dorper semen. In conclusion, neither fresh nor frozen-thawed Dorper and Dohne Merino semen collected via EE did differ significantly. Furthermore, except for semen volume, Dorper and Dohne Merino semen collected via AV did not differ significantly whether evaluated as fresh or frozen-thawed semen. However, both Dorper and Dohne Merino rams produced semen with higher motility and a higher percentage live sperm post-thaw when the semen samples were collected via an AV than via EE. From these results it can therefore be postulated that if Namaqua semen were collected via AV it could have a higher post-thaw percentage live sperm than if semen was collected via EE. Advanced further studies are necessary to investigate the reason for the lower post-thaw survival rate of sperm of the Namaqua Afrikaner rams. This is necessary as semen stored in a cryobank for breeding and conservation purposes for this endangered breed has to be of high quality. Such resources as cryobanks are expensive and funds cannot be wasted on preserving inferior samples that could not fertilize an ovum when needed. The low percentage of live sperm obtained with the frozen-thawed samples in this, as well as other studies on indigenous breeds, is an indication that further research is needed into more suitable freezing protocols. It can be concluded that Namaqua Afrikaner semen cannot be frozen successfully for the purpose of storage in a cryobank, when using a freezing protocol based on Triladyl® as extender. Furthermore, any increase in post-thaw survival rate of sperm will be beneficial and it is therefore suggested that all efforts be made to solve the problem of the Namaqua Afrikaner rams that do not want to ejaculate into an artificial vagina.
- Full Text:
- Date Issued: 2017
- Authors: Letsoalo, Phutiane Thomas
- Date: 2017
- Subjects: Merino sheep Dorper sheep Semen
- Language: English
- Type: Thesis , Masters , Animal Science
- Identifier: http://hdl.handle.net/10353/11707 , vital:39099
- Description: The aim of this study was to characterise and cryopreserve semen of the indigenous Namaqua Afrikaner breed, and to compare it to that of Dorper and Dohne Merino sheep, whose semen is commercially frozen on a large scale. The study was conducted between January and August 2015. September 2013-born Namaqua Afrikaner (12), Dohne Merino (12) and Dorper (9) rams were used in the study. The rams were kept under kraal conditions with adequate shade, and they received a high protein, high energy diet. Originally it was envisaged to collect semen samples using the artificial vagina (AV) method, which proved to be problematic with the Namaqua Afrikaner rams. Semen samples were subsequently collected twice a week by either AV (Dohne Merino and Dorper) or electro-ejaculation (EE; all three breeds). Macroscopic sperm traits were assessed and sperm concentration determined immediately after collection. Each semen sample was diluted with Triladyl® (1:3) and subsequently frozen in liquid nitrogen vapour in straws. Frozen straws were thawed and evaluated at 7, 30 and 90 days after cryopreservation. A droplet (0.5 ml) from each thawed sample was assessed microscopically for post-thaw motility and percentage live sperm. Nigrosin-Eosin smears were prepared of fresh, diluted and frozen-thawed semen samples for determination of percentage live sperm. Data of all the traits were analysed with the GLM and CHI-SQUARE procedures of the SAS statistical package. Breed had a significant effect on ejaculate volume of fresh semen collected either via electro-ejaculation or artificial vagina. Dorper rams (1.37 ± 0.08 ml) and Dohne Merino rams (1.20 ± 0.08 ml) produced ejaculates with higher (P <0.05) semen volume than Namaqua Afrikaner rams (1.09 ± 0.08 ml) when using the EE. With the AV method, Dohne Merino rams (1.46 ± 0.08 ml) produced a higher (P <0.05) ejaculate volume than Dorper rams (1.22 ± 0.08 ml). Motility of the frozen-thawed semen samples was lower than that of the fresh and diluted samples for all breeds and collection methods. Furthermore, motility 3 hours after thawing was also lower than motility assessed immediately after thawing for all breeds and collection methods. Motility of frozen-thawed semen collected with an AV and evaluated at 7, 30 and 90 days after freezing was significantly higher than that collected via EE. Dorper rams had the lowest sperm concentration (1.10 ± 5.29x109 sperm/ml) and the Namaqua rams the highest sperm concentration (1.22 ± 5.20x109 sperm/ml) (P ˂0.05). The AV samples had a higher (P >0.05) sperm concentration (1.20 ± 3.68x109 sperm/ml) than the EE samples (1.11 ± 3.51x109 sperm/ml). The percentage live sperm in the fresh semen samples did not differ among Namaqua Afrikaner (67.76 ± 1.94percent), Dohne Merino (68.59 ± 1.94percent) and Dorper (72.82 ± 1.98percent) rams. The percentage live sperm for all three breeds dropped considerably after freezing to 17.76 ± 2.03percent, 17.86 ± 2.03percent and 22.72 ± 2.07percent respectively. It remained constant for all the breeds from 7 until 90 days after freezing, indicating that length of storage should not have an effect on percentage live sperm for semen collected via AV or EE. Percentage live sperm of the frozen-thawed semen of the Namaqua rams was lower than that of the Dorper rams, indicating that the Namaqua semen collected via EE did not freeze as well as that of the Dorper semen. In conclusion, neither fresh nor frozen-thawed Dorper and Dohne Merino semen collected via EE did differ significantly. Furthermore, except for semen volume, Dorper and Dohne Merino semen collected via AV did not differ significantly whether evaluated as fresh or frozen-thawed semen. However, both Dorper and Dohne Merino rams produced semen with higher motility and a higher percentage live sperm post-thaw when the semen samples were collected via an AV than via EE. From these results it can therefore be postulated that if Namaqua semen were collected via AV it could have a higher post-thaw percentage live sperm than if semen was collected via EE. Advanced further studies are necessary to investigate the reason for the lower post-thaw survival rate of sperm of the Namaqua Afrikaner rams. This is necessary as semen stored in a cryobank for breeding and conservation purposes for this endangered breed has to be of high quality. Such resources as cryobanks are expensive and funds cannot be wasted on preserving inferior samples that could not fertilize an ovum when needed. The low percentage of live sperm obtained with the frozen-thawed samples in this, as well as other studies on indigenous breeds, is an indication that further research is needed into more suitable freezing protocols. It can be concluded that Namaqua Afrikaner semen cannot be frozen successfully for the purpose of storage in a cryobank, when using a freezing protocol based on Triladyl® as extender. Furthermore, any increase in post-thaw survival rate of sperm will be beneficial and it is therefore suggested that all efforts be made to solve the problem of the Namaqua Afrikaner rams that do not want to ejaculate into an artificial vagina.
- Full Text:
- Date Issued: 2017
Characterisation and cryopreservation of semen from indigenous Namaqua Afrikaner sheep breed, in comparison with Dorper and Dohne Merino breeds
- Authors: Letsoalo, Phutiane Thomas
- Date: 2017
- Subjects: Cryopreservation of organs, tissues, etc Merino sheep Dorper sheep
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10353/4759 , vital:28510
- Description: The aim of this study was to characterise and cryopreserve semen of the indigenous Namaqua Afrikaner breed, and to compare it to that of Dorper and Dohne Merino sheep, whose semen is commercially frozen on a large scale. The study was conducted between January and August 2015. September 2013-born Namaqua Afrikaner (12), Dohne Merino (12) and Dorper (9) rams were used in the study. The rams were kept under kraal conditions with adequate shade, and they received a high protein, high energy diet. Originally it was envisaged to collect semen samples using the artificial vagina (AV) method, which proved to be problematic with the Namaqua Afrikaner rams. Semen samples were subsequently collected twice a week by either AV (Dohne Merino and Dorper) or electro-ejaculation (EE; all three breeds). Macroscopic sperm traits were assessed and sperm concentration determined immediately after collection. Each semen sample was diluted with Triladyl® (1:3) and subsequently frozen in liquid nitrogen vapour in straws. Frozen straws were thawed and evaluated at 7, 30 and 90 days after cryopreservation. A droplet (0.5 ml) from each thawed sample was assessed microscopically for post-thaw motility and percentage live sperm..
- Full Text:
- Date Issued: 2017
- Authors: Letsoalo, Phutiane Thomas
- Date: 2017
- Subjects: Cryopreservation of organs, tissues, etc Merino sheep Dorper sheep
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10353/4759 , vital:28510
- Description: The aim of this study was to characterise and cryopreserve semen of the indigenous Namaqua Afrikaner breed, and to compare it to that of Dorper and Dohne Merino sheep, whose semen is commercially frozen on a large scale. The study was conducted between January and August 2015. September 2013-born Namaqua Afrikaner (12), Dohne Merino (12) and Dorper (9) rams were used in the study. The rams were kept under kraal conditions with adequate shade, and they received a high protein, high energy diet. Originally it was envisaged to collect semen samples using the artificial vagina (AV) method, which proved to be problematic with the Namaqua Afrikaner rams. Semen samples were subsequently collected twice a week by either AV (Dohne Merino and Dorper) or electro-ejaculation (EE; all three breeds). Macroscopic sperm traits were assessed and sperm concentration determined immediately after collection. Each semen sample was diluted with Triladyl® (1:3) and subsequently frozen in liquid nitrogen vapour in straws. Frozen straws were thawed and evaluated at 7, 30 and 90 days after cryopreservation. A droplet (0.5 ml) from each thawed sample was assessed microscopically for post-thaw motility and percentage live sperm..
- Full Text:
- Date Issued: 2017
Effects of loading time and lairage duration on pig behaviour, sex and lairage time on pork physio-chemical characteristics
- Authors: Ntlatywa, Bongiswa
- Date: 2017
- Subjects: Pork -- Quality Meat -- Quality Loading and unloading
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12270 , vital:39225
- Description: The objectives of the study were to determine the effect of loading time, transportation unloading and lairage period, their subsequent effect on responses behaviour and the effect of sex and lairage period on the meat quality of cross breeds reared in commercial farm. The first part of the study assessed the behaviour of pigs during loading at the farm, offloading and in the lairages. A total of 900 pigs from 5 trips (180 per trip) were monitored on behaviour from farm to slaughter plant. The pigs were transported to a commercial abattoir which is 120 km distance, travelling for 2 hours from the farm. The results revealed that time spent in loading pigs was more than when offloading pigs. The frequency of slipping or falling-off in pigs was high (18percent) than voluntary movement (8percent) during loading times (χ2 >0.05) that when off-loading. A significant difference was determined on the avoidance (χ2=0.03), mounting behaviour (χ2 =0.01) and vocal sound (χ2 =0.02) during loading time on each observation day. Furthermore there was no significant difference determined on the time and day of observation in the lairages. These results also reveal that the avoidance behaviour was the highest (47percent) while fighting (34percent) and vocalizing were the least compared to other behaviour during the first 30 minutes after arrival at the abattoir. Moreover, the lying behaviour was found to have highest frequency (15percent) on day 6 compared to other sampling days. These results reveal that time of loading pigs had an influence on pigs’ behaviour before slaughter and consequently that affected physiological features and meat quality. The second section of the study assessed sex and the different lairage time effects on the pork quality attributes. A total of fifty four pigs, 22 weeks old of different sex (26 boars x 28 gilts) reared on a commercial farm and transported to the abattoir on the same day was used in this study. At the abattoir, pigs were grouped according to lairage periods of 17 hours (Group1; 13 gilts and 14 boars) and 36 hours (Group 2; 15 gilts and 12 boars). Results showed no significant difference on the sex of pigs (P >0.05) and meat pH. However, lairage time influenced the thawing loss (P= 0.02) of meat and also the interactions of sex by lairage had a significant difference (P= 0.04) on meat tenderness. There was a positive significant correlation found between sex and meat attributes values were high in boars (r= 0.61) than in gilts (r = 0.49). A negative correlation between a*and WBSF on lairage group1 (r= -0.52) was determined while on group 2 there was a positive correlation between a* and b* (r=0.49). This study suggest that a proper timing on farm feed withdrawal in combination with a sufficient lairage at the slaughter plant may result in better carcass and meat quality traits. Communication among producers and abattoirs is critical when planning the fasting and lairage times in order to elude carcass and technological pork quality complications. To conclude, there is influence caused by time of loading in stressing pigs before transportation and slaughter as aggressive behaviour showed and also lairage time affected meat quality.
- Full Text:
- Date Issued: 2017
- Authors: Ntlatywa, Bongiswa
- Date: 2017
- Subjects: Pork -- Quality Meat -- Quality Loading and unloading
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12270 , vital:39225
- Description: The objectives of the study were to determine the effect of loading time, transportation unloading and lairage period, their subsequent effect on responses behaviour and the effect of sex and lairage period on the meat quality of cross breeds reared in commercial farm. The first part of the study assessed the behaviour of pigs during loading at the farm, offloading and in the lairages. A total of 900 pigs from 5 trips (180 per trip) were monitored on behaviour from farm to slaughter plant. The pigs were transported to a commercial abattoir which is 120 km distance, travelling for 2 hours from the farm. The results revealed that time spent in loading pigs was more than when offloading pigs. The frequency of slipping or falling-off in pigs was high (18percent) than voluntary movement (8percent) during loading times (χ2 >0.05) that when off-loading. A significant difference was determined on the avoidance (χ2=0.03), mounting behaviour (χ2 =0.01) and vocal sound (χ2 =0.02) during loading time on each observation day. Furthermore there was no significant difference determined on the time and day of observation in the lairages. These results also reveal that the avoidance behaviour was the highest (47percent) while fighting (34percent) and vocalizing were the least compared to other behaviour during the first 30 minutes after arrival at the abattoir. Moreover, the lying behaviour was found to have highest frequency (15percent) on day 6 compared to other sampling days. These results reveal that time of loading pigs had an influence on pigs’ behaviour before slaughter and consequently that affected physiological features and meat quality. The second section of the study assessed sex and the different lairage time effects on the pork quality attributes. A total of fifty four pigs, 22 weeks old of different sex (26 boars x 28 gilts) reared on a commercial farm and transported to the abattoir on the same day was used in this study. At the abattoir, pigs were grouped according to lairage periods of 17 hours (Group1; 13 gilts and 14 boars) and 36 hours (Group 2; 15 gilts and 12 boars). Results showed no significant difference on the sex of pigs (P >0.05) and meat pH. However, lairage time influenced the thawing loss (P= 0.02) of meat and also the interactions of sex by lairage had a significant difference (P= 0.04) on meat tenderness. There was a positive significant correlation found between sex and meat attributes values were high in boars (r= 0.61) than in gilts (r = 0.49). A negative correlation between a*and WBSF on lairage group1 (r= -0.52) was determined while on group 2 there was a positive correlation between a* and b* (r=0.49). This study suggest that a proper timing on farm feed withdrawal in combination with a sufficient lairage at the slaughter plant may result in better carcass and meat quality traits. Communication among producers and abattoirs is critical when planning the fasting and lairage times in order to elude carcass and technological pork quality complications. To conclude, there is influence caused by time of loading in stressing pigs before transportation and slaughter as aggressive behaviour showed and also lairage time affected meat quality.
- Full Text:
- Date Issued: 2017
Effects of Vigna unguiculata and Lablab purpureus on methanogenesis, haematological parameters and the quality of meat from Xhosa Lop Ear goats
- Authors: Washaya, Soul
- Date: 2017
- Subjects: Legumes Forage Forage plants
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/9996 , vital:35249
- Description: The objective of the current study was to evaluate the nutritive value of forage legumes Lablab purpureus (Lablab) and Vigna unguiculata (Cowpea) and their effects on intake, growth, blood parameters and meat quality in Xhosa goats. Forages were established at UFH research farm in the summer of the 2014 /15 growing season in blocks measuring 8m width x 16m long for each legume, replicated three times, making a total of four blocks, and eight treatment units for each legume. Samples were collected at three different stages of growth of preanthesis, anthesis and post anthesis for biomass yield determination. A homogenous sub-sample was then oven dried for 72 hours at 60 0C. After drying the forage samples were milled through a 1mm screen and a 20g sample from each stage of growth and forage sample was subjected to proximate analysis, in-vitro digestibility and anti-nutrient evaluation. The in-vitro digestibility experiment was done with rumen liquor of cattle and sheep collected from an abbatoir. Tannins, total phenolics and sapponins were the only anti-nutrients evaluated as they are perceived to influence methanogenesis in ruminat animals. At 50percent flowering, forage legumes were harvested for hay making which was then used in an in-vivo trial to evaluate the nutritive value of forages. This trial was conducted using eighteen one-year-old goats of average weight 14.2±0.24 kg over a period of sixty days. The results showed that biomass yield, which increased with stage of growth, was significantly higher (P < 0.05) for Lablab than Cowpea (7.968t/ha vs 7.105t/ha). Cowpea exhibited higher moisture content (7.72percent), Ash (13.11percent), acid detergent fibre (ADF) (38.42percent) and crude protein (CP) (20.23percent) than Lablab which had 7.50percent, 11.45 percent, 36.17percent and 19percent, respectively. Lablab forage had significantly higher (P < 0.05) fat content (2.41percent), neutral detergent fibre (NDF) (49.27percent) and hemicellulose (13.07percent) than Cowpea which had 2.1percent; 46.91percent and 8.48percent, respectively. The stage of growth significantly (P < 0.05) affected the mineral content of both forages. Lablab showed significantly higher (P < 0.05) values (1.22percent 0.55percent, 2.67percent) than Cowpea (1.00percent, 0.45percent, 2.30percent) for calcium (Ca), phosphorus (P), and potassium (K) respectively. Lablab forage had significantly higher (P < 0.05) tannin (3.345mgCAE/gDM), phenolic (13.47mgGAE/gDM) and saponin (0.75percent) content compared to Cowpea with values of 1.494mgCAEg/DM; 9.402mgGAE/gDM and vs 1.55percent respectively. The tannin content significantly influenced in-vitro digestibility and enteric methane production. The forage type, harvesting stage and inoculum source significantly (P < 0.05) affected the in-vitro digestibility of the forages. The in-vitro dry matter (IVDM) and in-vitro organic matter (IVOM) digestibility was significantly higher (P < 0.05) for Lablab (41.13percent; 39.63percent) than Cowpea (39.86percent; 19.44percent), respectively. Both forages recorded higher dry matter (DM) digestibility coefficients at anthesis stage of growth 61.58percent, and 51.5 percent for Lablab and Cowpea respectively. The IVOM digestibility increased with stage of harvest (23.7percent to 25.57percent) for Cowpea while Lablab showed a decrease (44.6 percent to 43.9percent) when cattle inoculum was used. The IVDM digestibility was higher (P < 0.05) for Lablab (50.5percent) when cattle inoculum was used while Cowpea was observed to have higher digestibility co-efficiencies (38.54percent) when sheep inoculum was used. Cowpea had lower (P < 0.05) IVOM digestibility than Lablab (19.44percent) vs. 39.6percent). Lablab exhibited higher (P < 0.05) metabolisable energy (ME) values than Cowpea (6.21 vs. 2.70 MJ/kgDM). In the feeding study, the total DM intake by goats for Lablab was higher (P < 0.05) compared to Cowpea (688.1 vs. 607.8 g/head/ day). There was a positive (P < 0.05) correlation between dry matter intake and average daily gain (r= 0.8513, and r=0.5279) for Cowpea and Lablab respectively. Lablab and Cowpea promoted growth of Xhosa goats at a rate of 35.0g/d; and 38.3g/d, respectively which was not significantly different (P > 0.05). However, this growth was associated with a significantly higher (P < 0.05) food conversion ratio (FCR) of 19.16 vs 18.11 for Cowpea and Lablab, respectively. The apparent DM, non structural carbohydrate (NSC) nutrient digestibilities were significantly different (P < 0.05) for Lablab and Cowpea. Furthermore sex of animal influenced significantly (P < 0.05) the DM, ADF, NSC and NDF digestibilities. Lablab and Cowpea did not influence (P > 0.05) individual VFA molar concentrations in both sexes. However, animals fed Lablab had significantly higher butyrate concentrations (P < 0.05). Lablab and Cowpea forages significantly lowered (P > 0.05) enteric methane production in goats compared to a concentrate diet, and this was related to animal activity. Animals produced significantly more (P < 0.05) methane gas when ruminating than feeding or just standing. The average methane produced each year was lower but not significant (P > 0.05) for animals fed Cowpea than Lablab (4.602kg CH4, vs. 4.719kg CH4) when expressed per year. Male animals produced more gas than females with values of 17.40L/day; 12.46 g/kg DMI and 0.126g/day vs. 15.47L/day, 12.28 g/kg DMI, and 0.0109g/day, respectively. Forage legumes had no significant effects (P > 0.05) on serum total proteins (TP), globulin, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma- glutamyl transferase (GGT) concentrations, but serum concentration of albumin was influenced by the diets (P < 0.05). Sex of animals significantly influenced ALP concentration (P < 0.05) with male animals exhibiting higer ALP values than females. Measured over time, the plasma concentration of urea and ALP significantly increased (P < 0.05) while creatinine and cholesterol concentration decreased (P < 0.05). Although the overall serum concentration of urea, total proteins, globulin, creatinine, ALT, ALP and GGT remained unchanged among the treatments and between sexes; treatment by sex, treatment by day and sex by day interactions were significant (P < 0.05). The white blood cell (WBC), red blood cell (RBC), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), haemoglobin, haematocrite, platelet and mean platelet volume (MPV) levels were similar among treatments and between sexes (P > 0.05). The WBC decreased with time by 8.07 x10 9/l while mean crepuscular volume (MCV) increased by 11.83(fl) from day 15 to day 55. Treatment diets significantly (P < 0.05) influenced neutrophile (percent) content while sex influenced basophile (percent) content. There were no treatment or sex effects (P > 0.05) on lymphocytes (percent), monocytes (percent) and eosinophiles (percent). In the meat quality study, the dietary treatments and sex had a significant (P < 0.05) effect on dressing out percent (DPpercent), initial pH, redness (a*), yellowness (b*), Warner Blartze Shear force (WBS) , drip loss and cooking loss in the chevon from Xhosa goats. Compared with a commercial pellet diet, Lablab and Cowpea diets resulted in similar slaughter body weights (SBW), hot carcass weight (HCW) and cold dressed mass (CDM) of carcasses. However, female animals exhibited a significantly (P < 0.05) higher DPpercent than male animals (42.3percent vs. 38.9percent) for all treatments. The male animals exhibited significantly (P < 0.05) higher pH values one hour after slaughter than females (5.79 vs 5.67). Neverthreless the diet and gender did not significantly (P > 0.05) affect the ultimate pH (pHu). Meat samples from male animals had significantly (P < 0.05) higher redness values than females. Feeding cowpea significantly (P < 0.05) increased meat redness with the least drip loss of chevon. Female animals produced significantly (P < 0.05) tougher chevon compared to male animals; 4.16kg and 3.36kg for female and male, respectively. Lablab and Cowpea posses high CP levels and moderately lower NDF with high ADF values that influences dry matter intake (DMI), digestibility and growth of goats. These forage legumes meet animal requirements for fat, ADF, NDF, CP, Ca, Mn, zinc and Cu and their biomass yield is satisfactory.
- Full Text:
- Date Issued: 2017
- Authors: Washaya, Soul
- Date: 2017
- Subjects: Legumes Forage Forage plants
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/9996 , vital:35249
- Description: The objective of the current study was to evaluate the nutritive value of forage legumes Lablab purpureus (Lablab) and Vigna unguiculata (Cowpea) and their effects on intake, growth, blood parameters and meat quality in Xhosa goats. Forages were established at UFH research farm in the summer of the 2014 /15 growing season in blocks measuring 8m width x 16m long for each legume, replicated three times, making a total of four blocks, and eight treatment units for each legume. Samples were collected at three different stages of growth of preanthesis, anthesis and post anthesis for biomass yield determination. A homogenous sub-sample was then oven dried for 72 hours at 60 0C. After drying the forage samples were milled through a 1mm screen and a 20g sample from each stage of growth and forage sample was subjected to proximate analysis, in-vitro digestibility and anti-nutrient evaluation. The in-vitro digestibility experiment was done with rumen liquor of cattle and sheep collected from an abbatoir. Tannins, total phenolics and sapponins were the only anti-nutrients evaluated as they are perceived to influence methanogenesis in ruminat animals. At 50percent flowering, forage legumes were harvested for hay making which was then used in an in-vivo trial to evaluate the nutritive value of forages. This trial was conducted using eighteen one-year-old goats of average weight 14.2±0.24 kg over a period of sixty days. The results showed that biomass yield, which increased with stage of growth, was significantly higher (P < 0.05) for Lablab than Cowpea (7.968t/ha vs 7.105t/ha). Cowpea exhibited higher moisture content (7.72percent), Ash (13.11percent), acid detergent fibre (ADF) (38.42percent) and crude protein (CP) (20.23percent) than Lablab which had 7.50percent, 11.45 percent, 36.17percent and 19percent, respectively. Lablab forage had significantly higher (P < 0.05) fat content (2.41percent), neutral detergent fibre (NDF) (49.27percent) and hemicellulose (13.07percent) than Cowpea which had 2.1percent; 46.91percent and 8.48percent, respectively. The stage of growth significantly (P < 0.05) affected the mineral content of both forages. Lablab showed significantly higher (P < 0.05) values (1.22percent 0.55percent, 2.67percent) than Cowpea (1.00percent, 0.45percent, 2.30percent) for calcium (Ca), phosphorus (P), and potassium (K) respectively. Lablab forage had significantly higher (P < 0.05) tannin (3.345mgCAE/gDM), phenolic (13.47mgGAE/gDM) and saponin (0.75percent) content compared to Cowpea with values of 1.494mgCAEg/DM; 9.402mgGAE/gDM and vs 1.55percent respectively. The tannin content significantly influenced in-vitro digestibility and enteric methane production. The forage type, harvesting stage and inoculum source significantly (P < 0.05) affected the in-vitro digestibility of the forages. The in-vitro dry matter (IVDM) and in-vitro organic matter (IVOM) digestibility was significantly higher (P < 0.05) for Lablab (41.13percent; 39.63percent) than Cowpea (39.86percent; 19.44percent), respectively. Both forages recorded higher dry matter (DM) digestibility coefficients at anthesis stage of growth 61.58percent, and 51.5 percent for Lablab and Cowpea respectively. The IVOM digestibility increased with stage of harvest (23.7percent to 25.57percent) for Cowpea while Lablab showed a decrease (44.6 percent to 43.9percent) when cattle inoculum was used. The IVDM digestibility was higher (P < 0.05) for Lablab (50.5percent) when cattle inoculum was used while Cowpea was observed to have higher digestibility co-efficiencies (38.54percent) when sheep inoculum was used. Cowpea had lower (P < 0.05) IVOM digestibility than Lablab (19.44percent) vs. 39.6percent). Lablab exhibited higher (P < 0.05) metabolisable energy (ME) values than Cowpea (6.21 vs. 2.70 MJ/kgDM). In the feeding study, the total DM intake by goats for Lablab was higher (P < 0.05) compared to Cowpea (688.1 vs. 607.8 g/head/ day). There was a positive (P < 0.05) correlation between dry matter intake and average daily gain (r= 0.8513, and r=0.5279) for Cowpea and Lablab respectively. Lablab and Cowpea promoted growth of Xhosa goats at a rate of 35.0g/d; and 38.3g/d, respectively which was not significantly different (P > 0.05). However, this growth was associated with a significantly higher (P < 0.05) food conversion ratio (FCR) of 19.16 vs 18.11 for Cowpea and Lablab, respectively. The apparent DM, non structural carbohydrate (NSC) nutrient digestibilities were significantly different (P < 0.05) for Lablab and Cowpea. Furthermore sex of animal influenced significantly (P < 0.05) the DM, ADF, NSC and NDF digestibilities. Lablab and Cowpea did not influence (P > 0.05) individual VFA molar concentrations in both sexes. However, animals fed Lablab had significantly higher butyrate concentrations (P < 0.05). Lablab and Cowpea forages significantly lowered (P > 0.05) enteric methane production in goats compared to a concentrate diet, and this was related to animal activity. Animals produced significantly more (P < 0.05) methane gas when ruminating than feeding or just standing. The average methane produced each year was lower but not significant (P > 0.05) for animals fed Cowpea than Lablab (4.602kg CH4, vs. 4.719kg CH4) when expressed per year. Male animals produced more gas than females with values of 17.40L/day; 12.46 g/kg DMI and 0.126g/day vs. 15.47L/day, 12.28 g/kg DMI, and 0.0109g/day, respectively. Forage legumes had no significant effects (P > 0.05) on serum total proteins (TP), globulin, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma- glutamyl transferase (GGT) concentrations, but serum concentration of albumin was influenced by the diets (P < 0.05). Sex of animals significantly influenced ALP concentration (P < 0.05) with male animals exhibiting higer ALP values than females. Measured over time, the plasma concentration of urea and ALP significantly increased (P < 0.05) while creatinine and cholesterol concentration decreased (P < 0.05). Although the overall serum concentration of urea, total proteins, globulin, creatinine, ALT, ALP and GGT remained unchanged among the treatments and between sexes; treatment by sex, treatment by day and sex by day interactions were significant (P < 0.05). The white blood cell (WBC), red blood cell (RBC), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), haemoglobin, haematocrite, platelet and mean platelet volume (MPV) levels were similar among treatments and between sexes (P > 0.05). The WBC decreased with time by 8.07 x10 9/l while mean crepuscular volume (MCV) increased by 11.83(fl) from day 15 to day 55. Treatment diets significantly (P < 0.05) influenced neutrophile (percent) content while sex influenced basophile (percent) content. There were no treatment or sex effects (P > 0.05) on lymphocytes (percent), monocytes (percent) and eosinophiles (percent). In the meat quality study, the dietary treatments and sex had a significant (P < 0.05) effect on dressing out percent (DPpercent), initial pH, redness (a*), yellowness (b*), Warner Blartze Shear force (WBS) , drip loss and cooking loss in the chevon from Xhosa goats. Compared with a commercial pellet diet, Lablab and Cowpea diets resulted in similar slaughter body weights (SBW), hot carcass weight (HCW) and cold dressed mass (CDM) of carcasses. However, female animals exhibited a significantly (P < 0.05) higher DPpercent than male animals (42.3percent vs. 38.9percent) for all treatments. The male animals exhibited significantly (P < 0.05) higher pH values one hour after slaughter than females (5.79 vs 5.67). Neverthreless the diet and gender did not significantly (P > 0.05) affect the ultimate pH (pHu). Meat samples from male animals had significantly (P < 0.05) higher redness values than females. Feeding cowpea significantly (P < 0.05) increased meat redness with the least drip loss of chevon. Female animals produced significantly (P < 0.05) tougher chevon compared to male animals; 4.16kg and 3.36kg for female and male, respectively. Lablab and Cowpea posses high CP levels and moderately lower NDF with high ADF values that influences dry matter intake (DMI), digestibility and growth of goats. These forage legumes meet animal requirements for fat, ADF, NDF, CP, Ca, Mn, zinc and Cu and their biomass yield is satisfactory.
- Full Text:
- Date Issued: 2017
Forage production, nutritive value and intake rates by goats of pigeon pea (Cajanus cajan (L.) forages grown in the subtropical region of South Africa
- Authors: Buthelezi, Lindokuhle Sizwe
- Date: 2017
- Subjects: Forage Pigeon pea Forage plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7852 , vital:30773
- Description: Different growth stages and drying methods were used to assess forage production, nutritive value and intake of leaves from three Cajanus cajan varieties (ICEAP 00557, ICEAP 01514 and CIMMYT 100/01). In the 2016/17 growing season, three complete randomized block designs (CRBD’s) were conducted. Regrowth parameters were measured during both the both vegetative and flowering stages. The plots were harvested at the flowering stage. Biomass yields were measured at the flowering stage. The harvested leaves were then dried under the two different drying methods. The methods used were shade- and oven-drying at 60 oC. This was used to determine dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and total non-structural carbohydrates (TNC) for the C. cajan varieties. Minerals Ca, Mg, K, Na, K/(Ca+Mg), P and Zn, Cu, Mn and Fe and phytochemicals condensed tannins, phenolic compounds and saponins were also analyzed. The intake rates and in vitro and in sacco ruminal degradabilities were also determined. The survival percentage was significantly different (P<0.05) only across the means of varieties. There was no significant difference (P>0.05) in the number of shoots per plant, stems per shoot and coppice stems produced by the three C. cajan varieties at vegetative and flowering stage. There was a significant difference (P<0.05) in the heights of plants recorded by the varieties only at flowering stage. The yields of fresh biomass in C. cajan was significantly different (P<0.05) across all the varieties harvested in 2016. In all the varieties there was a significant difference (P<0.05) in dry matter yield in both seasons of 2016 and 2017. The effect of browse varieties and drying methods showed a significant effect (P<0.05) on DM, CP, fat, NDIN, ADIN and hemicellulose content of varieties. There was little impact by varieties and drying methods (P<0.05) on ash, NDF, ADF, ADL, TNC and cellulose content of varieties. Varieties and drying method had no effect (P>0.05) on Ca, Mg and K except for Na and P. There was no effect caused by varieties and drying methods (P>0.05) on Zn and Mn with Cu and Fe being the exceptions. Oven drying showed an overall reduction in the tannin concentration on leaves while there was an increase in saponins. The different varieties had no effect (P>0.05) on the IIR, 0.0275±0.0089, 0.0275±0.0077 and 0.0409±0.0109 for Cv1, Cv2 and Cv3, respectively. The day of the trial and browse variety had an effect (P<0.05) on bite rate. However, the day of trial had no significant effect (P>0.05) on both bite size and the instantaneous intake rate. Individual goat had a significant effect (P<0.05) on bite rate. There was a significant difference (P<0.05) in the in vitro and in sacco rapidly degradable fractions (a) of all the three varieties but the drying method had no effect (P>0.05). The slowly degradable fraction (b) and degradation rate constant (c) of all varieties was not significantly different (P>0.05) on both drying methods during IV DaisyII procedure. However, b and c, in all the varieties was significantly different (P<0.05) in both drying methods during the in sacco procedure. There was no significant difference (P>0.05) in the mean potentially degradable fraction (a+b) across all C. cajan varieties during IV DaisyII procedure, however a+c of all varieties was significantly different (P<0.05) in both the drying methods during the in sacco procedure. The effective in vitro and in sacco degradability of the varieties was significantly different (P<0.05) with a rumen outflow rate of 2, 5 and 8 percent per hour. The shade-dried varieties had a higher (P<0.05) ED than the oven-dried materials during IV DaisyII and the in sacco procedures. It was concluded that the decline in yield of C. cajan during the study is a reflection of poor survival, the insufficient regeneration from seed, nutrient depletion over time and the extended dry seasons. Therefore, shade drying is commended method of drying forages.
- Full Text:
- Date Issued: 2017
- Authors: Buthelezi, Lindokuhle Sizwe
- Date: 2017
- Subjects: Forage Pigeon pea Forage plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7852 , vital:30773
- Description: Different growth stages and drying methods were used to assess forage production, nutritive value and intake of leaves from three Cajanus cajan varieties (ICEAP 00557, ICEAP 01514 and CIMMYT 100/01). In the 2016/17 growing season, three complete randomized block designs (CRBD’s) were conducted. Regrowth parameters were measured during both the both vegetative and flowering stages. The plots were harvested at the flowering stage. Biomass yields were measured at the flowering stage. The harvested leaves were then dried under the two different drying methods. The methods used were shade- and oven-drying at 60 oC. This was used to determine dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and total non-structural carbohydrates (TNC) for the C. cajan varieties. Minerals Ca, Mg, K, Na, K/(Ca+Mg), P and Zn, Cu, Mn and Fe and phytochemicals condensed tannins, phenolic compounds and saponins were also analyzed. The intake rates and in vitro and in sacco ruminal degradabilities were also determined. The survival percentage was significantly different (P<0.05) only across the means of varieties. There was no significant difference (P>0.05) in the number of shoots per plant, stems per shoot and coppice stems produced by the three C. cajan varieties at vegetative and flowering stage. There was a significant difference (P<0.05) in the heights of plants recorded by the varieties only at flowering stage. The yields of fresh biomass in C. cajan was significantly different (P<0.05) across all the varieties harvested in 2016. In all the varieties there was a significant difference (P<0.05) in dry matter yield in both seasons of 2016 and 2017. The effect of browse varieties and drying methods showed a significant effect (P<0.05) on DM, CP, fat, NDIN, ADIN and hemicellulose content of varieties. There was little impact by varieties and drying methods (P<0.05) on ash, NDF, ADF, ADL, TNC and cellulose content of varieties. Varieties and drying method had no effect (P>0.05) on Ca, Mg and K except for Na and P. There was no effect caused by varieties and drying methods (P>0.05) on Zn and Mn with Cu and Fe being the exceptions. Oven drying showed an overall reduction in the tannin concentration on leaves while there was an increase in saponins. The different varieties had no effect (P>0.05) on the IIR, 0.0275±0.0089, 0.0275±0.0077 and 0.0409±0.0109 for Cv1, Cv2 and Cv3, respectively. The day of the trial and browse variety had an effect (P<0.05) on bite rate. However, the day of trial had no significant effect (P>0.05) on both bite size and the instantaneous intake rate. Individual goat had a significant effect (P<0.05) on bite rate. There was a significant difference (P<0.05) in the in vitro and in sacco rapidly degradable fractions (a) of all the three varieties but the drying method had no effect (P>0.05). The slowly degradable fraction (b) and degradation rate constant (c) of all varieties was not significantly different (P>0.05) on both drying methods during IV DaisyII procedure. However, b and c, in all the varieties was significantly different (P<0.05) in both drying methods during the in sacco procedure. There was no significant difference (P>0.05) in the mean potentially degradable fraction (a+b) across all C. cajan varieties during IV DaisyII procedure, however a+c of all varieties was significantly different (P<0.05) in both the drying methods during the in sacco procedure. The effective in vitro and in sacco degradability of the varieties was significantly different (P<0.05) with a rumen outflow rate of 2, 5 and 8 percent per hour. The shade-dried varieties had a higher (P<0.05) ED than the oven-dried materials during IV DaisyII and the in sacco procedures. It was concluded that the decline in yield of C. cajan during the study is a reflection of poor survival, the insufficient regeneration from seed, nutrient depletion over time and the extended dry seasons. Therefore, shade drying is commended method of drying forages.
- Full Text:
- Date Issued: 2017
How phase feeding manipulation affects growth, performance, feed cost, carcass characteristics and the quality of meat from broilers
- Authors: Sokanyile, Sanda
- Date: 2017
- Subjects: Animal nutrition , Feeds , Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5565 , vital:29334
- Description: The main objective of the study was to determine how phase feeding manipulation affects growth performance, feed cost, carcass characteristics and quality of meat from broiler chickens. A total of 180 day old un-sexed broiler chicks (Cobb 500) were separated into 3 dietary treatments of 60 birds per treatment and each treatment was replicated 3 times with 20 birds per replicate. The dietary treatments were as follows: T1 (starter 1-7 days; grower 8-21 days; finisher 22-35 days), T2 (starter 1-14 days; grower 15-21 days, finisher 22-35 days) and T3 (starter 1-14 days; grower 15-28 days; finisher 29-35 days). Feed intake and body weight gains were recorded weekly in kilograms. Average daily gain and feed conversion ratio were computed weekly. At day 35, the chickens were slaughtered and 12 representative breast muscles from each treatment were used for the determination of muscle pH (pH1, pH24 and pH48) and colour coordinates (Lightness – L*, redness – a* and yellowness – b*) in triplicate at 1 hour, 24 hours and 48 hours post-mortem.Feed intake (FI), feed conversion ratio (FCR), average daily gain (ADG) and average body weight at slaughter (ABW) were not significant (P>0.05) amongst the treatments. The most cost efficient feed (which accumulated the cheapest cost feed per kg were) T1 (R11.32) and T3 (R11.32) although there was a slight difference in the gross profit of these treatments T1 (R45.71) and T3 (R44.48). Carcass characteristics were the same (P > 0.05) across the treatments except for the wing, thigh, drumstick and the breast (P < 0.05). T2 had the highest wing weight (166.63±8.60), T1 (113.03±8.60) and the lowest in T3 (74.46±8.60). The thigh weight were greater (P<0.05) in T2 (185.69±4.34); T1 (185.54±4.34) compared to T3 (166.97±4.34) which was lower. Treatments 1 (204.17±6.57), T2 (197±6.57) had heavier (P<0.05) breast weights than T3 (186.06±6.57). Dietary treatments had no significant effect (P > 0.05) on pH of the breast meat. No differences were observed in colour during the 1 hour period after slaughter. At 24 hours after slaughter, the L* values were different (P < 0.05) in T1 and T2 (44.3 ± 0.37; 43.7 ± 0.37), respectively, T1 and T3 were the same. The a*-values were different (P < 0.05) at 48 hours after slaughter for T1 and T3 (4.5 ± 0.27; 3.4 ± 0.27), T2 was the same as T1. It was therefore, concluded that since manipulation of starter phase did not have adverse effects on growth performance, gross profit, slight statistical difference in meat quality attributes and carcass characteristics. Therefore, the manipulation of starter diet has the potential to be used in broiler production.
- Full Text:
- Date Issued: 2017
- Authors: Sokanyile, Sanda
- Date: 2017
- Subjects: Animal nutrition , Feeds , Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5565 , vital:29334
- Description: The main objective of the study was to determine how phase feeding manipulation affects growth performance, feed cost, carcass characteristics and quality of meat from broiler chickens. A total of 180 day old un-sexed broiler chicks (Cobb 500) were separated into 3 dietary treatments of 60 birds per treatment and each treatment was replicated 3 times with 20 birds per replicate. The dietary treatments were as follows: T1 (starter 1-7 days; grower 8-21 days; finisher 22-35 days), T2 (starter 1-14 days; grower 15-21 days, finisher 22-35 days) and T3 (starter 1-14 days; grower 15-28 days; finisher 29-35 days). Feed intake and body weight gains were recorded weekly in kilograms. Average daily gain and feed conversion ratio were computed weekly. At day 35, the chickens were slaughtered and 12 representative breast muscles from each treatment were used for the determination of muscle pH (pH1, pH24 and pH48) and colour coordinates (Lightness – L*, redness – a* and yellowness – b*) in triplicate at 1 hour, 24 hours and 48 hours post-mortem.Feed intake (FI), feed conversion ratio (FCR), average daily gain (ADG) and average body weight at slaughter (ABW) were not significant (P>0.05) amongst the treatments. The most cost efficient feed (which accumulated the cheapest cost feed per kg were) T1 (R11.32) and T3 (R11.32) although there was a slight difference in the gross profit of these treatments T1 (R45.71) and T3 (R44.48). Carcass characteristics were the same (P > 0.05) across the treatments except for the wing, thigh, drumstick and the breast (P < 0.05). T2 had the highest wing weight (166.63±8.60), T1 (113.03±8.60) and the lowest in T3 (74.46±8.60). The thigh weight were greater (P<0.05) in T2 (185.69±4.34); T1 (185.54±4.34) compared to T3 (166.97±4.34) which was lower. Treatments 1 (204.17±6.57), T2 (197±6.57) had heavier (P<0.05) breast weights than T3 (186.06±6.57). Dietary treatments had no significant effect (P > 0.05) on pH of the breast meat. No differences were observed in colour during the 1 hour period after slaughter. At 24 hours after slaughter, the L* values were different (P < 0.05) in T1 and T2 (44.3 ± 0.37; 43.7 ± 0.37), respectively, T1 and T3 were the same. The a*-values were different (P < 0.05) at 48 hours after slaughter for T1 and T3 (4.5 ± 0.27; 3.4 ± 0.27), T2 was the same as T1. It was therefore, concluded that since manipulation of starter phase did not have adverse effects on growth performance, gross profit, slight statistical difference in meat quality attributes and carcass characteristics. Therefore, the manipulation of starter diet has the potential to be used in broiler production.
- Full Text:
- Date Issued: 2017
Seasonal variations in tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of extensively raised Boran cows
- Authors: Ntilini, Wonga John
- Date: 2017
- Subjects: Boran cattle -- South Africa Ticks -- South Africa
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13471 , vital:39672
- Description: This study sought to determine the seasonal variations in tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of Boran cows reared in arid rangelands of South Africa. A total of 20 Boran cows of different age groups were used in this study. Tick counts, hair length, coat score, average temperature and relative humidity readings were measured twice (beginning and end) in each season (post-rainy, cold-dry, hot-dry, hot-wet). Blood samples were taken seasonally (beginning and end of the season) for the analysis of creatine kinase (CK) activity and haematological parameters (HP). Ticks were observed and counted from different anatomical sites, namely anterior (neck, head, ears, and around eyes), ventral (belly, udder, and limbs) and posterior (back and under the tail). The tick species observed from the Boran cows were Rhipicephalus evertsi evertsi (34.58percent), Amblyomma hebreaum (43.35percent), Rhipicephalus simus (4.48percent) and Rhipicephalus (Boophilus) decoloratus (17.59percent). Significant differences were observed in tick burdens at various anatomical sites, with posterior position having the highest tick loads during the post-rainy, cold-dry and hot-dry season. While the ventral position recorded the highest tick loads during the hot-wet season. It was also observed that the cattle had significantly long hair lengths during the cold-dry season. Furthermore, coat score and hair length were observed to be negatively (P<0.05) correlated with tick counts, while coat scores were positively (P<0.05) correlated with hair length. Significant differences were observed in CK activity across season, with higher levels during the hot-dry and hot-wet seasons compared to the post-rainy and cold-dry seasons. Boran cows were exposed to a mild stress condition during the hot-dry and hot-wet season when the THI values were high (>70). Seasonal variations had an effect (P<0.05) on some HP (HB, HCT, MCV, MCH, EOS, and BAS). Neutrophils (-0.267) and basophils (0.268) were significantly correlated with THI. In conclusion, the Boran cows were more susceptible to tick loads during the hot seasons. Likewise, the levels of creatine kinase activity and temperature-humidity index were high during the hot-dry and hot-wet season. Therefore, seasonal variations had an effect on tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of extensively raised Boran cows.
- Full Text:
- Date Issued: 2017
- Authors: Ntilini, Wonga John
- Date: 2017
- Subjects: Boran cattle -- South Africa Ticks -- South Africa
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13471 , vital:39672
- Description: This study sought to determine the seasonal variations in tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of Boran cows reared in arid rangelands of South Africa. A total of 20 Boran cows of different age groups were used in this study. Tick counts, hair length, coat score, average temperature and relative humidity readings were measured twice (beginning and end) in each season (post-rainy, cold-dry, hot-dry, hot-wet). Blood samples were taken seasonally (beginning and end of the season) for the analysis of creatine kinase (CK) activity and haematological parameters (HP). Ticks were observed and counted from different anatomical sites, namely anterior (neck, head, ears, and around eyes), ventral (belly, udder, and limbs) and posterior (back and under the tail). The tick species observed from the Boran cows were Rhipicephalus evertsi evertsi (34.58percent), Amblyomma hebreaum (43.35percent), Rhipicephalus simus (4.48percent) and Rhipicephalus (Boophilus) decoloratus (17.59percent). Significant differences were observed in tick burdens at various anatomical sites, with posterior position having the highest tick loads during the post-rainy, cold-dry and hot-dry season. While the ventral position recorded the highest tick loads during the hot-wet season. It was also observed that the cattle had significantly long hair lengths during the cold-dry season. Furthermore, coat score and hair length were observed to be negatively (P<0.05) correlated with tick counts, while coat scores were positively (P<0.05) correlated with hair length. Significant differences were observed in CK activity across season, with higher levels during the hot-dry and hot-wet seasons compared to the post-rainy and cold-dry seasons. Boran cows were exposed to a mild stress condition during the hot-dry and hot-wet season when the THI values were high (>70). Seasonal variations had an effect (P<0.05) on some HP (HB, HCT, MCV, MCH, EOS, and BAS). Neutrophils (-0.267) and basophils (0.268) were significantly correlated with THI. In conclusion, the Boran cows were more susceptible to tick loads during the hot seasons. Likewise, the levels of creatine kinase activity and temperature-humidity index were high during the hot-dry and hot-wet season. Therefore, seasonal variations had an effect on tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of extensively raised Boran cows.
- Full Text:
- Date Issued: 2017
Species composition and seasonal population dynamics of free-living and engorged cattle ticks in three agro-ecological zones of the Eastern Cape Province, South Africa
- Authors: Yawa, Mandla
- Date: 2017
- Subjects: Ticks Boophilus microplus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9067 , vital:34224
- Description: This study was conducted to determine species composition and seasonal population dynamics of free-living and engorged cattle ticks in three agro-ecological zones (Bedford dry grassland, Kowie thicket and Bisho thornveld) of the Eastern Cape Province, South Africa. The occurrence of ticks on cattle was studied monthly from April 2016 and March 2017. Tick collections were performed on 360 selected cattle in each agro-ecological zones. During tick collections, 10 randomly selected cattle were sampled at each locality and more attention was given to African blue tick and the presence of Asian blue tick. A half body tick collection was performed from cattle and visible ticks were collected by means of fine-forceps after the animals had been restrained. Body regions that were examined includes the ear, head, neck, chest, abdomen, flank, front and hind leg and feet, tail, and peri-anal region. At each locality, six replicate drags of 100 m, approximately 50 m apart, were performed to collect ticks from vegetation. All ticks collected per cattle and from vegetation were stored in labelled sample tubes containing 70percent ethanol, subsequently counted and identified to genus and species level using a standard stereomicroscope. A total of 31425 ticks belonging to ten species were collected during the study. Rhipicephalus (Boophilus) decoloratus, was the most observed tick species (32.50percent), all other ticks like R. evertsi evertsi (18.84percent), R. appendiculatus (17.26percent), A. hebraeum (16.27percent), R. simus (7.69percent) were also commonly collected. Ixodes pilosus (3.84percent), H. rufipes (3.46percent), R. follis (0.08percent) together with Haemaphysalis silacea (0.02percent) were sporadic infestation. Haemaphysalis elliptica (0.04percent) was only found on the vegetation. No H. rufipes was collected in the thicket vegetation. Agro-ecological zones differ significantly (P<0.05) in tick species and distribution. Significantly more R. (B.) decoloratus were collected in thicket during summer compared to thornveld and dry grassland regions (P<0.05). Free-living ticks were widely distributed across different seasons but with of R. (B.) decoloratus larvae were significantly higher (P<0.05) in thornveld region during the spring season. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. From this study, it is of interest to note the absence of R. (B.) microplus, whose trend to invade new areas previously colonised by R. (B.) decoloratus has been observed in Africa. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. The aforementioned absence of R. (B.) microplus in this study highlights the importance of further research as this tick invades new areas previously colonised by R. (B.) decoloratus in the continent.
- Full Text:
- Date Issued: 2017
- Authors: Yawa, Mandla
- Date: 2017
- Subjects: Ticks Boophilus microplus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9067 , vital:34224
- Description: This study was conducted to determine species composition and seasonal population dynamics of free-living and engorged cattle ticks in three agro-ecological zones (Bedford dry grassland, Kowie thicket and Bisho thornveld) of the Eastern Cape Province, South Africa. The occurrence of ticks on cattle was studied monthly from April 2016 and March 2017. Tick collections were performed on 360 selected cattle in each agro-ecological zones. During tick collections, 10 randomly selected cattle were sampled at each locality and more attention was given to African blue tick and the presence of Asian blue tick. A half body tick collection was performed from cattle and visible ticks were collected by means of fine-forceps after the animals had been restrained. Body regions that were examined includes the ear, head, neck, chest, abdomen, flank, front and hind leg and feet, tail, and peri-anal region. At each locality, six replicate drags of 100 m, approximately 50 m apart, were performed to collect ticks from vegetation. All ticks collected per cattle and from vegetation were stored in labelled sample tubes containing 70percent ethanol, subsequently counted and identified to genus and species level using a standard stereomicroscope. A total of 31425 ticks belonging to ten species were collected during the study. Rhipicephalus (Boophilus) decoloratus, was the most observed tick species (32.50percent), all other ticks like R. evertsi evertsi (18.84percent), R. appendiculatus (17.26percent), A. hebraeum (16.27percent), R. simus (7.69percent) were also commonly collected. Ixodes pilosus (3.84percent), H. rufipes (3.46percent), R. follis (0.08percent) together with Haemaphysalis silacea (0.02percent) were sporadic infestation. Haemaphysalis elliptica (0.04percent) was only found on the vegetation. No H. rufipes was collected in the thicket vegetation. Agro-ecological zones differ significantly (P<0.05) in tick species and distribution. Significantly more R. (B.) decoloratus were collected in thicket during summer compared to thornveld and dry grassland regions (P<0.05). Free-living ticks were widely distributed across different seasons but with of R. (B.) decoloratus larvae were significantly higher (P<0.05) in thornveld region during the spring season. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. From this study, it is of interest to note the absence of R. (B.) microplus, whose trend to invade new areas previously colonised by R. (B.) decoloratus has been observed in Africa. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. The aforementioned absence of R. (B.) microplus in this study highlights the importance of further research as this tick invades new areas previously colonised by R. (B.) decoloratus in the continent.
- Full Text:
- Date Issued: 2017
The effect of quantitative feed restriction on growth performance, carcass characteristics and selected meat quality parameters in broiler chickens
- Authors: Velele, Siphelo
- Date: 2017
- Subjects: Broilers (Chickens) Poultry -- Breeding Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8888 , vital:33907
- Description: The study investigated the effects of quantitative feed restriction on growth performance, carcass characteristics, internal organs, breast muscle pH and meat colour in broiler chickens. A total of 90, un-sexed, day-old broiler chicks were procured from an accredited supplier and were used for the current trial. For the first 14 days, all birds were brooded in one house and subjected to a uniform day-to-day management. Water was supplied throughout the trial, whereas, feed was only supplied ad libitum between days 1-14 and 29-35 days in feed restricted birds. Feed phases included starter (1-14 days), grower (15-28) and finisher (29-35), respectively. On day 15, birds were randomly allocated to three treatments; each treatment was replicated three times with 10 birds per replicate. The first treatment (T1) group, which acted as control group, was ad libitum feeding for the whole trial duration (1-35 days). For treatments 2 (T2) and 3(T3), 85 percent and 70 percent of the Cobb 500 broiler feed intake standards were applied for a period of 14 days (days 15-28), respectively. Average daily feed intake (ADFI) was determined daily and then average body weight (ABW) was determined weekly. Feed conversion ratio and average daily weight gain was thus computed for each experimental unit (replicate). On day 35, broiler birds were electrically stunned and slaughtered by a sharp knife and then hung for complete bleeding. Data collected included slaughter, carcass, breast, thigh, wing, drumstick, feet, head, spleen, heart, gizzard, intestines (small & large) and liver weights. Breast muscle was further used for the determination of colour (L*, b* and a*), initial (pHi) and ultimate breast pH (pHu) measurements. Although, quantitative feed restriction (T2 & T3) significantly affected growth performance in weeks 3 and 4, birds submitted to T2 performed similar (P>0.05) to control in the final stage, whilst birds in T3 was the poorest (P<0.05). Furthermore, birds subjected to T2 showed no differences of edible carcass portions to the control, however, T3 group showed lower (P<0.05) slaughter and wing weights. Breast ultimate pH values of birds under T2 were similar to control, but birds in T3 had significantly higher (P<0.05) values. Birds under T2 had less (P<0.05) reddish breast meat colour than control at 45 minutes. At 24 hours post-mortem, birds in T3 had lower (P<0.05) lightness values and birds submitted to T2 had higher (P<0.05) yellowness values. Liver weight was significantly lower in birds under T3 and higher (P<0.05) gizzard weights were found in birds subjected to T2. Birds under T2 performed similar to control and were able to compensate for the weight loss when high plane of feed was re-introduced. It can be concluded from the results that restricting 15 percent of feed from Cobb 500 standard feed intake had moderately affected broiler performance. Moreover, restricting 15percent of feed significantly reduced feed intake in broiler chicken.
- Full Text:
- Date Issued: 2017
- Authors: Velele, Siphelo
- Date: 2017
- Subjects: Broilers (Chickens) Poultry -- Breeding Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8888 , vital:33907
- Description: The study investigated the effects of quantitative feed restriction on growth performance, carcass characteristics, internal organs, breast muscle pH and meat colour in broiler chickens. A total of 90, un-sexed, day-old broiler chicks were procured from an accredited supplier and were used for the current trial. For the first 14 days, all birds were brooded in one house and subjected to a uniform day-to-day management. Water was supplied throughout the trial, whereas, feed was only supplied ad libitum between days 1-14 and 29-35 days in feed restricted birds. Feed phases included starter (1-14 days), grower (15-28) and finisher (29-35), respectively. On day 15, birds were randomly allocated to three treatments; each treatment was replicated three times with 10 birds per replicate. The first treatment (T1) group, which acted as control group, was ad libitum feeding for the whole trial duration (1-35 days). For treatments 2 (T2) and 3(T3), 85 percent and 70 percent of the Cobb 500 broiler feed intake standards were applied for a period of 14 days (days 15-28), respectively. Average daily feed intake (ADFI) was determined daily and then average body weight (ABW) was determined weekly. Feed conversion ratio and average daily weight gain was thus computed for each experimental unit (replicate). On day 35, broiler birds were electrically stunned and slaughtered by a sharp knife and then hung for complete bleeding. Data collected included slaughter, carcass, breast, thigh, wing, drumstick, feet, head, spleen, heart, gizzard, intestines (small & large) and liver weights. Breast muscle was further used for the determination of colour (L*, b* and a*), initial (pHi) and ultimate breast pH (pHu) measurements. Although, quantitative feed restriction (T2 & T3) significantly affected growth performance in weeks 3 and 4, birds submitted to T2 performed similar (P>0.05) to control in the final stage, whilst birds in T3 was the poorest (P<0.05). Furthermore, birds subjected to T2 showed no differences of edible carcass portions to the control, however, T3 group showed lower (P<0.05) slaughter and wing weights. Breast ultimate pH values of birds under T2 were similar to control, but birds in T3 had significantly higher (P<0.05) values. Birds under T2 had less (P<0.05) reddish breast meat colour than control at 45 minutes. At 24 hours post-mortem, birds in T3 had lower (P<0.05) lightness values and birds submitted to T2 had higher (P<0.05) yellowness values. Liver weight was significantly lower in birds under T3 and higher (P<0.05) gizzard weights were found in birds subjected to T2. Birds under T2 performed similar to control and were able to compensate for the weight loss when high plane of feed was re-introduced. It can be concluded from the results that restricting 15 percent of feed from Cobb 500 standard feed intake had moderately affected broiler performance. Moreover, restricting 15percent of feed significantly reduced feed intake in broiler chicken.
- Full Text:
- Date Issued: 2017
The use of behaviour, saliva cortisol and faecal glucocorticoid levels as stress indicators in beef cows
- Authors: Dzviti, Melody
- Date: 2017
- Subjects: Veterinary physiology Beef cattle -- Behavior Glucocorticoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8165 , vital:31634
- Description: The study evaluated the use of saliva as a minimally invasive technique for cortisol level determination. This was done by assessing the relationship between serum and saliva cortisol based on short sampling intervals. In addition, the study also determined the effect of successive handling on faecal glucocorticoid metabolites (FGM), rectal temperature (RT), avoidance distance (AD), chute and crush scores as well as urination, defaecation and vocalization in multiparous cows. For trial one six non-pregnant, clinically healthy Nguni cows were used. They were administered with standardised doses of adrenocorticotropic hormone on treatment days and saline was used as a placebo on alternative days. Simultaneously, blood and saliva samples were collected to quantify cortisol levels. No relationship (r = 0.0131, P>0.05) was observed between serum and saliva cortisol. However, results showed that there was adrenal stimulation in saliva coupled by significant (P<0.05) effects of sampling intervals. For the second study 21 non-pregnant and clinically healthy Nguni cows of one herd were used for the trial. They were divided into parity groups and their weights were used as a covariate in data analysis. For five consecutive weeks, fresh faecal samples were extracted and rectal temperatures measured. In addition, fear of approaching humans was assessed by AD scores and behaviour scores in the crush chute, as well as vocalisation, urination and defaecation were observed. The effect of successive handling significantly (P<0.05) affected the physiological parameters, namely FGM and RT. Contrariwise, Chi-square tests revealed that parities had a significant (χ2 < 0.05) influence on AD and crush scores as well as on the occurrence of excretory behaviour. It was concluded that saliva cortisol can be used as a stress indicator in beef cows. However, plasma cortisol can be significantly volatile thereby becoming less sensitive to changes across time. This can cause a lack of relationship between plasma and saliva cortisol. On the other hand, repetitive handling of beef cows has an influence on faecal stress levels. In addition, beef cows of differing parities behave differently to handling stress.
- Full Text:
- Date Issued: 2017
- Authors: Dzviti, Melody
- Date: 2017
- Subjects: Veterinary physiology Beef cattle -- Behavior Glucocorticoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8165 , vital:31634
- Description: The study evaluated the use of saliva as a minimally invasive technique for cortisol level determination. This was done by assessing the relationship between serum and saliva cortisol based on short sampling intervals. In addition, the study also determined the effect of successive handling on faecal glucocorticoid metabolites (FGM), rectal temperature (RT), avoidance distance (AD), chute and crush scores as well as urination, defaecation and vocalization in multiparous cows. For trial one six non-pregnant, clinically healthy Nguni cows were used. They were administered with standardised doses of adrenocorticotropic hormone on treatment days and saline was used as a placebo on alternative days. Simultaneously, blood and saliva samples were collected to quantify cortisol levels. No relationship (r = 0.0131, P>0.05) was observed between serum and saliva cortisol. However, results showed that there was adrenal stimulation in saliva coupled by significant (P<0.05) effects of sampling intervals. For the second study 21 non-pregnant and clinically healthy Nguni cows of one herd were used for the trial. They were divided into parity groups and their weights were used as a covariate in data analysis. For five consecutive weeks, fresh faecal samples were extracted and rectal temperatures measured. In addition, fear of approaching humans was assessed by AD scores and behaviour scores in the crush chute, as well as vocalisation, urination and defaecation were observed. The effect of successive handling significantly (P<0.05) affected the physiological parameters, namely FGM and RT. Contrariwise, Chi-square tests revealed that parities had a significant (χ2 < 0.05) influence on AD and crush scores as well as on the occurrence of excretory behaviour. It was concluded that saliva cortisol can be used as a stress indicator in beef cows. However, plasma cortisol can be significantly volatile thereby becoming less sensitive to changes across time. This can cause a lack of relationship between plasma and saliva cortisol. On the other hand, repetitive handling of beef cows has an influence on faecal stress levels. In addition, beef cows of differing parities behave differently to handling stress.
- Full Text:
- Date Issued: 2017
Adaptive responses to heat stress, quality of hide and meat from indigenous Nguni and non-descript crossbred cattle
- Authors: Chikwanda, Denice
- Date: 2016
- Subjects: Cattle -- Effect of temperature on Nguni cattle Beef cattle breeds
- Language: English
- Type: Thesis , Doctoral , PhD (Agriculture)
- Identifier: http://hdl.handle.net/10353/10614 , vital:35635
- Description: The main objective of this study was to determine the adaptive responses of Nguni and non-descript crossbred cattle (NDCC) to heat stress, nutritionally-related blood metabolite profiles, fatty acid profiles, carcass and meat characteristics, physico-mechanical properties of automotive upholstery crust leather and the associated collagen fibre architecture of hides and crust leather. Forty steers (20 Nguni and 20 NDCC) which were approximately 14 months of age with live weights ranging between 153 kg and 203 kg at the beginning of the study were used. Environmental variables (ambient temperature, relative humidity, wind parameters, solar radiation) were collected from a weather station at the research farm. Temperature-humidity index (THI) values were computed. Rectal and skin temperature, skin traits and blood metabolites were determined at two-week intervals over 16 weeks. Hair coat scores ranged from extremely short (score 1) to very woolly (score 7). At slaughter, blood samples were collected after exsanguination. Meat samples were collected from the right muscularis longissimus thoracis et lumborum (LTL) and Triceps brachii (TB) muscles after 24 hours of chilling of carcasses for physico-chemical quality tests. Fatty acid profiles and physico-chemical quality of meat were determined on the LTL and TB. An additional fifty-four hides (27 Nguni and 27 NDCC) were obtained from a commercial abattoir at slaughter. The hides were tanned into automotive crust leather and tested for physico-mechanical quality. Results showed that week and environmental variables affected skin temperature; also, the rectal and skin temperatures were negatively correlated to body condition, skin pigment, coat score and skin thickness. Non-descript crossbred cattle had higher coat scores (2.1 ± 0.36 to 4.1 ± 4.20) than Nguni cattle (1.6 ± 0.36 to 4.1 ± 0.36). Body condition scores, blood creatinine, urea, total protein, albumin and globulin were affected by genotype and week of sampling. At the end of the trial, NDCC had higher slaughter and hide weights (285.9 ± 6.52 kg and 18.4 ± 0.54 kg, respectively) than Nguni cattle (232.6 ± 6.5 kg and 14.7 ± 0.54 kg, respectively). The majority of NDCC carcasses (73.7 percent) had a fatness level of 1 compared to Nguni carcasses (50 percent). Intramuscular fat was higher in Nguni (1.8 ± 0.09 percent) compared to NDCC (1.5 ± 0.09 percent) steers. Nguni steers had darker muscle colour (L*=33.6 ± 0.01) than NDCC (L*= 35.7 ± 0.54). Nguni and NDCC had similar thawing loss, cooking loss, WBSF tenderness, fat-free dry matter, moisture content, fatty acid profiles and health-related lipid indices. Ultimate muscle pH, meat colour and chroma were similar in the LTL and TB. Concerning the skin, Nguni and NDCC had similar physico-mechanical properties. However, breaking load and tensile strength were higher (1257.1 ± 70.72 N and 28.3 ± 1.23 MPa) in samples taken parallel to the backbone compared to that taken perpendicular to the backbone (979.5 ±70.72 N and 23.6 ±1.23MPa) across the two genotypes. Non-descript crossbred crust leather varied in physico-mechanical tests by direction of sampling. Collagen fibre orientation in hides and crust samples also varied between longitudinal and cross-sections. Collagen fibre diameters in the Nguni were similar in longitudinal and cross-sections (3.4 ± 0.12 μm and 3.2 ± 0.11 μm, respectively). From this study, it is concluded that THI, hair coat, skin traits and body condition affect skin temperature, but not rectal temperature, cortisol and CK activity in Nguni and NDCC reared extensively. The two genotypes differ in nutritionally-related blood metabolites, growth performance, hide weights and carcass traits. Beef from Nguni and NDCC differs in the IMF and meat lightness but is similar in the meat fatty acid composition and some physico-chemical quality parameters. Automotive crust leathers from the two genotypes were similar in some physico-mechanical properties. Collagen architecture varied among different regions of hides and crust leathers
- Full Text:
- Date Issued: 2016
- Authors: Chikwanda, Denice
- Date: 2016
- Subjects: Cattle -- Effect of temperature on Nguni cattle Beef cattle breeds
- Language: English
- Type: Thesis , Doctoral , PhD (Agriculture)
- Identifier: http://hdl.handle.net/10353/10614 , vital:35635
- Description: The main objective of this study was to determine the adaptive responses of Nguni and non-descript crossbred cattle (NDCC) to heat stress, nutritionally-related blood metabolite profiles, fatty acid profiles, carcass and meat characteristics, physico-mechanical properties of automotive upholstery crust leather and the associated collagen fibre architecture of hides and crust leather. Forty steers (20 Nguni and 20 NDCC) which were approximately 14 months of age with live weights ranging between 153 kg and 203 kg at the beginning of the study were used. Environmental variables (ambient temperature, relative humidity, wind parameters, solar radiation) were collected from a weather station at the research farm. Temperature-humidity index (THI) values were computed. Rectal and skin temperature, skin traits and blood metabolites were determined at two-week intervals over 16 weeks. Hair coat scores ranged from extremely short (score 1) to very woolly (score 7). At slaughter, blood samples were collected after exsanguination. Meat samples were collected from the right muscularis longissimus thoracis et lumborum (LTL) and Triceps brachii (TB) muscles after 24 hours of chilling of carcasses for physico-chemical quality tests. Fatty acid profiles and physico-chemical quality of meat were determined on the LTL and TB. An additional fifty-four hides (27 Nguni and 27 NDCC) were obtained from a commercial abattoir at slaughter. The hides were tanned into automotive crust leather and tested for physico-mechanical quality. Results showed that week and environmental variables affected skin temperature; also, the rectal and skin temperatures were negatively correlated to body condition, skin pigment, coat score and skin thickness. Non-descript crossbred cattle had higher coat scores (2.1 ± 0.36 to 4.1 ± 4.20) than Nguni cattle (1.6 ± 0.36 to 4.1 ± 0.36). Body condition scores, blood creatinine, urea, total protein, albumin and globulin were affected by genotype and week of sampling. At the end of the trial, NDCC had higher slaughter and hide weights (285.9 ± 6.52 kg and 18.4 ± 0.54 kg, respectively) than Nguni cattle (232.6 ± 6.5 kg and 14.7 ± 0.54 kg, respectively). The majority of NDCC carcasses (73.7 percent) had a fatness level of 1 compared to Nguni carcasses (50 percent). Intramuscular fat was higher in Nguni (1.8 ± 0.09 percent) compared to NDCC (1.5 ± 0.09 percent) steers. Nguni steers had darker muscle colour (L*=33.6 ± 0.01) than NDCC (L*= 35.7 ± 0.54). Nguni and NDCC had similar thawing loss, cooking loss, WBSF tenderness, fat-free dry matter, moisture content, fatty acid profiles and health-related lipid indices. Ultimate muscle pH, meat colour and chroma were similar in the LTL and TB. Concerning the skin, Nguni and NDCC had similar physico-mechanical properties. However, breaking load and tensile strength were higher (1257.1 ± 70.72 N and 28.3 ± 1.23 MPa) in samples taken parallel to the backbone compared to that taken perpendicular to the backbone (979.5 ±70.72 N and 23.6 ±1.23MPa) across the two genotypes. Non-descript crossbred crust leather varied in physico-mechanical tests by direction of sampling. Collagen fibre orientation in hides and crust samples also varied between longitudinal and cross-sections. Collagen fibre diameters in the Nguni were similar in longitudinal and cross-sections (3.4 ± 0.12 μm and 3.2 ± 0.11 μm, respectively). From this study, it is concluded that THI, hair coat, skin traits and body condition affect skin temperature, but not rectal temperature, cortisol and CK activity in Nguni and NDCC reared extensively. The two genotypes differ in nutritionally-related blood metabolites, growth performance, hide weights and carcass traits. Beef from Nguni and NDCC differs in the IMF and meat lightness but is similar in the meat fatty acid composition and some physico-chemical quality parameters. Automotive crust leathers from the two genotypes were similar in some physico-mechanical properties. Collagen architecture varied among different regions of hides and crust leathers
- Full Text:
- Date Issued: 2016
Characterisation of the production and consumption of milk in the communal livestock production sector of the Eastern Cape Province, South Africa
- Authors: Kumbirai, Kaguru Tinashe
- Date: 2016
- Subjects: Milk consumption -- South Africa -- Eastern Cape Dairy farming -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/3066 , vital:28251
- Description: The study was conducted in Eastern Cape Province, South Africa with the objective of characterising milk production and consumption among the communal households. A pretested semi-structured questionnaire was used to collect data through a single visit survey between June 2014 and May 2015. The study was undertaken in five randomly selected communal districts using a multi – stage area probability sampling method. Household sample size was calculated using a statistical methodology through a fixed formula based on a rural population size of 4410000, at a confidence level of 95 percent. A total of 500 households were selected with a sample size of 20 households in 5 communities within five different communal districts within the province. Half of the total sample size was used to represent the number of non-milk producing households (250) to get a true reflection on consumption profiles for nonproducers. Across the province the average communal family size was between 5-10 members with a monthly income of ZAR1340 per household. On average, pasture land size of the sampled households was 1 ha, with a range of 0.25-1.7 ha. The numbers of animals per species found in the studied province was highest for sheep (310) followed by cattle (227) and goat (87). Average livestock holding per household in the study area was 9.85 TLU (Tropical Livestock Unit). According to the respondents the predominant milking livestock numbers were between 1-3 animals milking per household. In the studied area traditional hand milking of livestock was the major milking practices at 12 percent in goats, 15 percent in sheep and 45 percent in cattle milk production. Consumption was the predominant reason for milk production recorded at 27 percent across the province. Milk production was 43 percent most preferred in cattle followed by 32 percent in goat and least at 29 percent in sheep across the province. In general, from the study it was noted that the majority (38 percent) of the respondents across the province indicated 0-5mins as the time it took to milk most milk producing livestock. The majority of the milking practices was done (37 percent) predominantly once a day, followed by 2 percent twice daily across the province. The daily milk production was on average (0.45±1.07) 2-5 litre in cattle, (4.86±0.814) 0-1litre in goats and (2.62±0.42) 0-1 litre sheep per producing house hold with in the province The monthly raw milk consumption in the province was (2.20± 1.42) 2-5 litres of cattle milk, (4.78±0.79) 2-5 litres of goat milk and (4.98±0.69) 2-5 litres of sheep milk per consuming household.
- Full Text:
- Date Issued: 2016
- Authors: Kumbirai, Kaguru Tinashe
- Date: 2016
- Subjects: Milk consumption -- South Africa -- Eastern Cape Dairy farming -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/3066 , vital:28251
- Description: The study was conducted in Eastern Cape Province, South Africa with the objective of characterising milk production and consumption among the communal households. A pretested semi-structured questionnaire was used to collect data through a single visit survey between June 2014 and May 2015. The study was undertaken in five randomly selected communal districts using a multi – stage area probability sampling method. Household sample size was calculated using a statistical methodology through a fixed formula based on a rural population size of 4410000, at a confidence level of 95 percent. A total of 500 households were selected with a sample size of 20 households in 5 communities within five different communal districts within the province. Half of the total sample size was used to represent the number of non-milk producing households (250) to get a true reflection on consumption profiles for nonproducers. Across the province the average communal family size was between 5-10 members with a monthly income of ZAR1340 per household. On average, pasture land size of the sampled households was 1 ha, with a range of 0.25-1.7 ha. The numbers of animals per species found in the studied province was highest for sheep (310) followed by cattle (227) and goat (87). Average livestock holding per household in the study area was 9.85 TLU (Tropical Livestock Unit). According to the respondents the predominant milking livestock numbers were between 1-3 animals milking per household. In the studied area traditional hand milking of livestock was the major milking practices at 12 percent in goats, 15 percent in sheep and 45 percent in cattle milk production. Consumption was the predominant reason for milk production recorded at 27 percent across the province. Milk production was 43 percent most preferred in cattle followed by 32 percent in goat and least at 29 percent in sheep across the province. In general, from the study it was noted that the majority (38 percent) of the respondents across the province indicated 0-5mins as the time it took to milk most milk producing livestock. The majority of the milking practices was done (37 percent) predominantly once a day, followed by 2 percent twice daily across the province. The daily milk production was on average (0.45±1.07) 2-5 litre in cattle, (4.86±0.814) 0-1litre in goats and (2.62±0.42) 0-1 litre sheep per producing house hold with in the province The monthly raw milk consumption in the province was (2.20± 1.42) 2-5 litres of cattle milk, (4.78±0.79) 2-5 litres of goat milk and (4.98±0.69) 2-5 litres of sheep milk per consuming household.
- Full Text:
- Date Issued: 2016
Consumer perceptions and microbial quality of meat sold in the informal markets of Nkonkobe and Buffalo City municipalities in the Eastern province, South Africa
- Authors: Mazizi, Bulelani Elvis
- Date: 2016
- Subjects: Meat -- Quality -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15365 , vital:40401
- Description: The main objective of the study was to determine consumer perceptions and microbial quality of meat sold in the informal markets found in Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa. To determine consumer perceptions of the quality of the meat and meat products sold in the informal markets in Nkonkobe and Buffalo City Municipalities, a survey was conducted. A total of 160 consumers from two municipalities in the Eastern Cape (EC) Province of South Africa was randomly sampled and interviewed. A questionnaire was used to gather information about consumer perceptions of meat and meat products sold in the informal markets regarding their knowledge about safety, food-borne diseases, hygiene, and the quality of the meat among others. The study showed that Alice Town has a larger (66.25percent) proportion of consumers with knowledge about foodborne diseases while King Williams’s Town had a larger proportion (48.75percent) of respondents who had no knowledge about Food-borne diseases. However, a large proportion of consumers in King Williams’s Town considered vendor (82.5percent) and environmental hygiene (93.75percent) than in Alice Town. Consumers (83.75percent) in King Williams’s Town viewed the meat from street vendors to be of low quality while a small proportion (18.75percent) of consumers in Alice Town viewed it as the meat of good quality. Alice had a large proportion (61.25percent) of consumers, which had knowledge of the meat safety law than King Williams’s Town. More consumers from King Williams’s Town (31.25percent) agreed that government plays a role while Alice had a small proportion (26.25percent) which disagreed. The results also showed that consumer perceptions about the safety of meat and meat products are focused more on hygiene, neglecting other important aspects such as vending infrastructure. However, most consumers do not have enough knowledge concerning meat safety. The second study determined the microbial quality of meat sold by street vendors based in Alice and Kind Williams Town in the Eastern Cape Province South Africa. A total of 48 fresh and uncooked meat samples (beef, pork, and mutton), 48 surface contact plates and 40 water samples was collected from 4 street vendors from each town for microbial analysis (n=48). After collection, all samples were subjected to Aerobic plate count (APC), Salmonella spp, Staphylococcus aureus (Staph) and Escherichia coli (E. coli). The results revealed that Salmonella spp tested negative across all the meat samples used in the study. However, no significant differences were found in the microbial quality of meat sold by street vendors in Alice and King Williams town. Furthermore, there were no significant differences (P>0.05) between the APC of raw beef (4.8 Log CFU/g), mutton (3.7 Log CFU/g) and pork (2.8 Log CFU/g) and also the cooked beef (1.5 Log CFU/g), mutton (1.3 Log CFU/g) and pork (1.9 Log CFU/g) samples. A similar trend was observed in the values of Staphylococcus aureus (Staph) and Escherichia coli (E. coli) counts in raw and cooked meat samples. However, a positive correlation between Aerobic plate counts (APC) and Staphylococcus aureus (Staph) (P<0.001) and Escherichia coli (E. coli) (P<0.01) was found in the study. It can, therefore, be concluded that there were no differences in the microbial counts of raw and cooked meat sold in the informal markets of Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Mazizi, Bulelani Elvis
- Date: 2016
- Subjects: Meat -- Quality -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15365 , vital:40401
- Description: The main objective of the study was to determine consumer perceptions and microbial quality of meat sold in the informal markets found in Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa. To determine consumer perceptions of the quality of the meat and meat products sold in the informal markets in Nkonkobe and Buffalo City Municipalities, a survey was conducted. A total of 160 consumers from two municipalities in the Eastern Cape (EC) Province of South Africa was randomly sampled and interviewed. A questionnaire was used to gather information about consumer perceptions of meat and meat products sold in the informal markets regarding their knowledge about safety, food-borne diseases, hygiene, and the quality of the meat among others. The study showed that Alice Town has a larger (66.25percent) proportion of consumers with knowledge about foodborne diseases while King Williams’s Town had a larger proportion (48.75percent) of respondents who had no knowledge about Food-borne diseases. However, a large proportion of consumers in King Williams’s Town considered vendor (82.5percent) and environmental hygiene (93.75percent) than in Alice Town. Consumers (83.75percent) in King Williams’s Town viewed the meat from street vendors to be of low quality while a small proportion (18.75percent) of consumers in Alice Town viewed it as the meat of good quality. Alice had a large proportion (61.25percent) of consumers, which had knowledge of the meat safety law than King Williams’s Town. More consumers from King Williams’s Town (31.25percent) agreed that government plays a role while Alice had a small proportion (26.25percent) which disagreed. The results also showed that consumer perceptions about the safety of meat and meat products are focused more on hygiene, neglecting other important aspects such as vending infrastructure. However, most consumers do not have enough knowledge concerning meat safety. The second study determined the microbial quality of meat sold by street vendors based in Alice and Kind Williams Town in the Eastern Cape Province South Africa. A total of 48 fresh and uncooked meat samples (beef, pork, and mutton), 48 surface contact plates and 40 water samples was collected from 4 street vendors from each town for microbial analysis (n=48). After collection, all samples were subjected to Aerobic plate count (APC), Salmonella spp, Staphylococcus aureus (Staph) and Escherichia coli (E. coli). The results revealed that Salmonella spp tested negative across all the meat samples used in the study. However, no significant differences were found in the microbial quality of meat sold by street vendors in Alice and King Williams town. Furthermore, there were no significant differences (P>0.05) between the APC of raw beef (4.8 Log CFU/g), mutton (3.7 Log CFU/g) and pork (2.8 Log CFU/g) and also the cooked beef (1.5 Log CFU/g), mutton (1.3 Log CFU/g) and pork (1.9 Log CFU/g) samples. A similar trend was observed in the values of Staphylococcus aureus (Staph) and Escherichia coli (E. coli) counts in raw and cooked meat samples. However, a positive correlation between Aerobic plate counts (APC) and Staphylococcus aureus (Staph) (P<0.001) and Escherichia coli (E. coli) (P<0.01) was found in the study. It can, therefore, be concluded that there were no differences in the microbial counts of raw and cooked meat sold in the informal markets of Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa.
- Full Text:
- Date Issued: 2016
Effect of Moringa oleifera leaf meal on growth performance, faecal ammonia emissions, carcass characteristics and the quality of meat from broiler chickens
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
Effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Date Issued: 2016
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Date Issued: 2016