Water restriction and vitamin c supplementation on Xhosa goats during summer: Effect on growth performance, blood biochemical profile, nutrient balance, carcass characteristics and meat quality
- Authors: Akinmoladun, Oluwakamisi Festus https://orcid.org/0000-0001-6462-374X
- Date: 2020-08
- Subjects: Goats -- Nutrition , Goats -- Feeding and feeds
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22710 , vital:52664
- Description: This study aimed to evaluate the effect of single and extra vitamin C (VC) supplementation on water-stressed Xhosa goats during the summer by evaluating their growth performance, blood biochemical profile, nutrient balance, carcass characteristics and meat qualities. The objectives were to assess the effect of water restriction and vitamin C supplementation by evaluating: firstly, growth performance, heat tolerance responses, and blood metabolites; secondly, intake, nutrient digestibility, nitrogen and mineral balance; thirdly, stress indices, carcass characteristics and meat qualities parameters and lastly, fatty acid profile, oxidative stability of lipids and sensory attributes were evaluated. To achieve these objectives, forty-two (42) goats were divided equally into seven treatments (75-day trial); without water restriction (W0, control); water restriction of 70percent of ad libitum water intake WI (W70); water restriction of 50percent ad libitum WI (W50); water restriction of 70percent of ad libitum WI plus 3g VC daily (W70+); water restriction 50percent of ad libitum WI plus 3g VC daily (W50+); water restriction of 70percent of ad libitumWI plus 3g VC and extra 5gVC given every eight-day (70++); water restriction of 50percent of ad libitum WI plus 3g VC and extra 5gVC given every eight-day (W50++). In the first objective, growth performance parameters, body condition scores, rectal temperature, respiratory rate, heat tolerance response parameters and blood metabolites were measured.Weight loss due to water restriction was reduced by VC supplementation in treated groups. The attenuation effect of VC was significant (P<0.05) in responses to respiratory rate (RR), Na+, K+, Mg2+, Cl-, Ca2+ and urea. Supplementation of VC (either single or multiple) did not (P>0.05) improve the effect of water restriction on body condition scores (BCs), FAMACHA©, glucose, globulin, alanine aminotransferase (ALT) and high-density lipoprotein (HDL). In the second objective, intake, nutrient digestibility, nitrogen and mineral balance were evaluated. The reduced nutrient intake was similar (P>0.05) irrespective of water restrictions and VC supplementations. Water-restriction levels did not affect nutrient intake/metabolic weight. Retained nitrogen increased with water-restriction levels but not influenced by VC. NH3-N decreased with the levels of water restriction while the pH was similar across the water restricted groups. Supplementation of VC had no effect (P>0.05) on apparent digestibility and digestible nutrients induced by water restriction levels. The amount of Ca, K, Mg retained increased (P<0.05) with water-restriction levels. In the third objective, stress indices, carcass characteristics and meat quality parameters were evaluated. The level of plasma cortisol concentration due to water stress was lessened (P<0.05) by VC. Follicle stimulating hormone (FSH), Luteinizing hormone (LH) and insulin were not affected (P>0.05) by levels of water restriction. The hot and carcass weights were lower (P<0.05) in W70+ and W50+ compared to W70 and W50 respectively. Vitamin C treated goats had higher redness (a*) compared to W70, W50 and W0. The shear force and cooking loss increased (P<0.05) with water restriction levels, while thaw loss, pH45min and pH24h were not affected by water restriction levels. In the final objective, the treatments did not affect (P>0.05) the oxidative stability of lipids (TBARS). The moisture and fat content in the water restricted groups were lower (P<0.05) than W0. The consumer meat sensory appearance decreased (P<0.05) with levels of water restrictions. Regardless of VC concentration and supplementation, vaccenic, and docosahexaenoic acid increased (P<0.05) while linolenic acid decreased as the water restriction levels increased. Nonetheless, treatment did not affect (P>0.05) the saturated and unsaturated fatty acids. These studies showed that suboptimal water intake negatively affects the growth performance and nutrient intake of Xhosa goats. However, the reduction in body weight loss and decreased plasma cortisol (chief stress hormone) concentration following vitamin C supplementation (especially at a daily single dose [3g/d]) may well reduce the effect of water stress in goats. , Thesis (PhD) -- Faculty of Science and Agriculture, 2020
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Effects of dietary supplementation on physico-chemical and consumer sensory characteristics of chevon from South African indigenous goat genotypes
- Authors: Xazela, Nomasonto Martha
- Date: 2010
- Subjects: Color of meat , Food -- Sensory evaluation , Commercial products -- Testing , Goats -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11809 , http://hdl.handle.net/10353/357 , Color of meat , Food -- Sensory evaluation , Commercial products -- Testing , Goats -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Description: The study was conducted at the University of Fort Hare farm to assess the effect of dietary supplementation on physico-chemical and consumer sensory characteristics of chevon from South African indigenous goat genotypes. Forty-eight 6-month-old Xhosa lop-eared (XLE), Nguni (NGN), Xhosa-Boer cross (XBC) and Boer (BOR) castrated goats with a body weight range from 20 to 25 kg were used in this study. Half of the goats in each genotype were supplemented with 200g/head/day of sunflower cake. The other half of goats in each genotype was not supplemented. The goats were slaughtered at day 90 to determine slaughter weight (SLW), cold dress mass (CDM), meat colour, cooking loss, meat pH and Warner-Bratzler (WB) shear force values. Furthermore, a consumer sensory evaluation of cooked or fried chevon from supplemented and non-supplemented goats was conducted with consumers of different ages, tribes and gender. The XLE and NGN goats had higher pH24 (P < 0.05) than BOR and XBC goats. Supplemented BOR goats had higher L* values than their non-supplemented counterparts (P < 0.05). The other meat quality attributes in XLE and NGN were comparable to those in meat from the Boer goat. Female respondents gave higher (P < 0.05) sensory scores than male respondents for both cooked and fried meat on aroma intensity. Shona consumers gave higher (P < 0.05) aroma intensity scores than the Xhosa and the Zulu consumers for both cooked and fried meat. In the non-supplemented goats, fried meat for all genotypes was superior (P < 0.05) to the cooked meat for initial impression of juiciness. Age and gender of respondents and thermal iv treatment influenced initial impression of juiciness scores (P < 0.05). The quality of chevon from XLE and NGN was comparable to that of the Boer goat, and dietary supplementation improved most meat quality attributes. Chevon from the supplemented goats had higher consumer sensory scores than chevon from the non-supplemented goats. Keywords: supplementation, meat colour, ultimate pH, consumer sensory evaluation, Xhosa lop eared, Nguni, Boer goats.
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Feeding behaviour of Xhosa lop-eared, Nguni and Nguni x Boer goat genotypes kept on rangelands of the false thornveld
- Authors: Bakare, Archibold Garikayi
- Date: 2009
- Subjects: Goats -- Feeding and feeds , Goats -- South Africa , Rangelands -- South Africa , Grazing -- South Africa , Veld
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11811 , http://hdl.handle.net/10353/396 , Goats -- Feeding and feeds , Goats -- South Africa , Rangelands -- South Africa , Grazing -- South Africa , Veld
- Description: Feeding behaviour of Xhosa lop-eared, Nguni and Nguni × Boer goat genotypes kept on rangelands of the False Thornveld By Archibold Garikayi Bakare The study was conducted at the University of Fort Hare farm to assess the feeding behaviour of three goat genotypes: Xhosa lop-eared (XLE), Nguni (NGN) and Nguni × Boer crossbred (NBC) genotypes. The time spent on different activities (grazing, browsing and other activities) on rangelands was recorded using stop watches. The micro-histological faecal analysis technique was used to identify and quantify the plant species that were consumed by the goats across the four seasons. Time spent browsing was high in post-rainy season for XLE (55.94 %) compared to NGN (52.97 %) and crossbred NBC (45.95 %) goats. The high browsing activity was also noted for XLE in hot-wet and cool-dry season (P < 0.05). The NBC goats on the other hand; devoted most of their time grazing compared to XLE and NGN goats across seasons (P < 0.05). Generally, time of day had no effect (P > 0.05) on foraging activities among the goat breeds. Grewia occidentalis, Panicum maximum and Diospyros lycioides were the most preferred plant species by all genotypes across seasons in the paddock. It was concluded that crossbreds spent more time grazing as compared to XLE, which are more of browsers. It could, therefore, be recommended that XLE complement with grazers (cattle and sheep) for efficient management of feed resources in rangelands.
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