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:
- 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.
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Primiparous and multiparous cow behaviour of friesland, jersey and cross-bred cows around calving time and during milking
- Authors: Mpisana, Zuko
- Date: 2015
- Subjects: Dairy products--Analysis Jersey cattle Milk yield
- Language: English
- Type: Thesis , Masters , Animal Science
- Identifier: http://hdl.handle.net/10353/16113 , vital:40665
- Description: The objective of the study was to determine effect of behaviour of primiparous and multiparous Friesland, Jersey and Cross-bred cows around calving time and during milking of first lactating cows in a pasture-based dairy system. The trial was conducted at the Fort Hare dairy farm. All pregnant primiparous and multiparous were kept in a maternity paddock. Five observers monitored the cows from the onset of parturition until the calf was fully expelled using digital stop watches. The behavioural responses of the cows during parturition (frequency and duration of lying, standing and walking bouts; calf licking; suckling) and milking (avoidance distance scores (ADS), entrance score, (ES), exit speed (ES), feeding score (FS), and the occurrence of stepping (STP) and kicking (KCK)) were determined on eighty consecutive days. The behavioural attributes were analysed using generalised linear model of procedure of SAS (2003). One hundred and twenty pregnant cows were used in the study, comprising of forty cows per genotype in different parities (A-primiparous, B- 2 to 4, C-5 to 6 and D-7 to 8) and kept in a maternity paddock. Five observers monitored cows from the onset of parturition until the calf was fully expelled. There were differences (P < 0.05) observed on the behavioural patterns around the time of calving. Jersey multiparous cows spent (P < 0.05) significantly most of their time (20.50±3.10) in lying position as compared to the other genotypes. The Jersey genotype also spent most (P < 0.05) of their time (48.00±0.34) in a standing position during calving period. Friesland cows spent (P < 0.05) most of their time (12.00±1.19) exhibiting either stepping or walking attributes as compared to Jersey and Crossbred cows. The Jersey genotype spent significantly (P < 0.05) more time (123.00±10.43) expelling calves compared to the other genotypes. Crossbred cows had the highest avoidance distance (14percent) scores compared to other genotypes and the Friesland cows had the lowest distance scores. The occurrence of kicking was significantly (P < 0.05) higher for the Friesland cows (57.3percent) compared to Jersey (23.2percent) and Crossbred cows (19.6percent). The Friesland cows had the highest (P < 0.05) frequency (36.2percent) feeding score compared to Jersey and Crossbred cows. The Jersey cows had the highest (60.2percent) exit speed compared to other genotypes. The occurrence of stepping was higher for the Friesland cows (53.9percent). The Friesland cows had the highest (P < 0.05) daily milk yield compared to Jersey and Crossbred cows. The present study revealed that behavioural activities of dairy cattle during parturition differed according to genotype and parity and the behavioural response of first lactating cows differ according to genotype during milking.
- Full Text:
- Authors: Mpisana, Zuko
- Date: 2015
- Subjects: Dairy products--Analysis Jersey cattle Milk yield
- Language: English
- Type: Thesis , Masters , Animal Science
- Identifier: http://hdl.handle.net/10353/16113 , vital:40665
- Description: The objective of the study was to determine effect of behaviour of primiparous and multiparous Friesland, Jersey and Cross-bred cows around calving time and during milking of first lactating cows in a pasture-based dairy system. The trial was conducted at the Fort Hare dairy farm. All pregnant primiparous and multiparous were kept in a maternity paddock. Five observers monitored the cows from the onset of parturition until the calf was fully expelled using digital stop watches. The behavioural responses of the cows during parturition (frequency and duration of lying, standing and walking bouts; calf licking; suckling) and milking (avoidance distance scores (ADS), entrance score, (ES), exit speed (ES), feeding score (FS), and the occurrence of stepping (STP) and kicking (KCK)) were determined on eighty consecutive days. The behavioural attributes were analysed using generalised linear model of procedure of SAS (2003). One hundred and twenty pregnant cows were used in the study, comprising of forty cows per genotype in different parities (A-primiparous, B- 2 to 4, C-5 to 6 and D-7 to 8) and kept in a maternity paddock. Five observers monitored cows from the onset of parturition until the calf was fully expelled. There were differences (P < 0.05) observed on the behavioural patterns around the time of calving. Jersey multiparous cows spent (P < 0.05) significantly most of their time (20.50±3.10) in lying position as compared to the other genotypes. The Jersey genotype also spent most (P < 0.05) of their time (48.00±0.34) in a standing position during calving period. Friesland cows spent (P < 0.05) most of their time (12.00±1.19) exhibiting either stepping or walking attributes as compared to Jersey and Crossbred cows. The Jersey genotype spent significantly (P < 0.05) more time (123.00±10.43) expelling calves compared to the other genotypes. Crossbred cows had the highest avoidance distance (14percent) scores compared to other genotypes and the Friesland cows had the lowest distance scores. The occurrence of kicking was significantly (P < 0.05) higher for the Friesland cows (57.3percent) compared to Jersey (23.2percent) and Crossbred cows (19.6percent). The Friesland cows had the highest (P < 0.05) frequency (36.2percent) feeding score compared to Jersey and Crossbred cows. The Jersey cows had the highest (60.2percent) exit speed compared to other genotypes. The occurrence of stepping was higher for the Friesland cows (53.9percent). The Friesland cows had the highest (P < 0.05) daily milk yield compared to Jersey and Crossbred cows. The present study revealed that behavioural activities of dairy cattle during parturition differed according to genotype and parity and the behavioural response of first lactating cows differ according to genotype during milking.
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