A review of factors affecting goat meat quality and mitigating strategies

Goat meat is increasing in popularity worldwide due to a growing demand for lean and nutritious meat. It is important to have an understanding of factors affecting goat meat quality in order to ensure the best possible quality acceptable to consumers. This paper reviews current knowledge on key factors and strategies for improving goat meat quality. Among animal factors, the breed/genetics and age at slaughter are key to goat meat quality. Conditioning of goats destined for slaughter can improve the quality of meat through more desirable carcass fat content. It has been established that goat carcasses have low glycolytic potential and consequently yield higher pH meat, therefore, minimising ante-mortem stress is important for goat meat quality. Goat carcasses are very small and lean, therefore, chilling conditions should be carefully monitored in order to minimise the risk of cold shortening. Electrical stimulation of carcasses has been reported to improve goat meat tenderness. Pelvic suspension of goat carcasses may result in improved meat tenderness compared to Achilles-hung carcasses. Post-slaughter ageing can further improve the tenderness of goat meat. Several efforts have been made to address the concerns pertaining to goat meat quality, but the challenge now is to promote the consumption of goat meat among diverse consumers and establish it as a dietetically acceptable red meat source.The National Research Foundation (NRF)http://www.elsevier.com/locate/smallrumres2021-02-01hj2020Animal and Wildlife Science

Effect of dietary inclusion of Azadirachta indica and Moringa oleifera leaf extracts on the carcass quality and fatty acid composition of lambs fed High forage total mixed rations

There is an increased interest in the use of medicinal plants as alternatives to antibiotic growth promoters and as agents for methane production mitigation. This study investigated the effects of Azadirachta indica and Moringa oleifera feed additives on the carcass and meat quality of lambs. Forty South African Mutton Merino lambs, weighing between 29 and 43 kg, were randomly assigned to four treatment groups (n = 10 lambs/treatment) and fed a basal total mixed ration (TMR) containing soybean meal (17%), yellow maize (28%), Alfalfa hay (20%), Eragrostis curvula hay (22.2%), molasses (6.0%), wheat offal (5%), urea (0.8%) and vitamin premix (0.5%) on a DM basis. The dietary treatments: TMR diet (control); TMR diet with A. indica leaf extract (A. indica leaf extract at a dosage of 50 mg per kg of feed: neem); TMR diet with M. oleifera leaf extract (M. oleifera leaf extract at a dosage of 50 mg per kg DM of feed: moringa); TMR diet with monensin (at a dosage of 50 mg monensin sodium per kg of feed: positive control). After an adaptation period of 10 days to the experimental conditions, the lambs from all treatment groups were fed ad libitum with the experimental diets. The lambs were slaughtered at a live weight of 60–65 kg after a 23 week trial period. The plant extract dietary additives had no significant effects on the carcass characteristics of the lambs. In comparison to monensin, supplementing with moringa leaf extracts resulted in a higher proportion of C18:1n9c (45.0% 0.57 vs. 40.5% 0.80; p < 0.05), total MUFAs (47.3% 0.66 vs. 42.6% 0.87; p < 0.05), and UFA:SFA ratio (1.01 0.03 vs. 0.85 0.03; p < 0.05), which may be beneficial for human health. Our results suggest that natural feed additives, such as A. indica and M. oleifera leaf extracts, can be included in lamb diets without compromising meat fatty acid composition. The negative economic impacts of such technologies on animal production and farm profitability should not be expected.The National Research Foundation (NRF).https://www.mdpi.com/journal/animalsam2023Animal and Wildlife Science

Effects of electrical stimulation and delayed chilling on carcass and meat quality of indigenous and Boer goats in South Africa

This study investigated the effects of electrical stimulation and delayed chilling on carcass and meat quality of indigenous and Boer goats in South Africa. Ten goats per breed were randomly selected from typical indigenous and Boer goats. The goats were slaughtered and dressed according to standard abattoir procedures. The goat carcasses were split into left and right sides along the vertebral column. Electrical stimulation (400 V for 30 seconds then chilling at 0 - 4 °C) or delayed chilling (10 - 15 °C for 6 hours, 0 - 4 °C until 24 hours) were applied to the carcass sides. Muscle fibre characteristics, the concentration of glycolytic metabolites, pH/temperature profiles, water holding capacity (WHC), thawing losses, evaporative losses, drip losses, cooking losses, surface myoglobin pigments, instrumental colour, sarcomere lengths and Warner Bratzler shear force (WBSF) values were evaluated on samples of both the m. longissimus dorsi (LD) and m. semimembranosus (SM). Carcasses of Boer goats were on average 2.9 kg heavier (P <0.001) than carcasses of indigenous goats. Dressing percentage was not different between the two goat breeds (47.5 ± 0.55%). Chilling losses were higher (P <0.01) in carcasses of Boer goats (4.81 ± 0.19%) than in carcasses of indigenous goats (4.03 ± 0.12%). The goat muscles were predominantly oxidative, with an average composition of 47 - 51%, 22 - 27% and 22 - 29% for red, intermediate and white fibres, respectively. The LD samples of indigenous goats had smaller (P <0.05) intermediate fibre cross sectional areas (2670 μm2 vs. 3510 μm2) and a higher (P <0.05) percentage of oxidative fibres (50.9% vs. 40.7%) than corresponding Boer goat samples. The composition of SM fibres of the two goat breeds were similar. Electrical stimulation hastened the rate of pH decline and muscle energy metabolism whilst delayed chilling showed slow but steady changes in pH and metabolic concentrations. Both slaughter procedures allowed carcasses to enter into rigor mortis without the risk of cold shortening (pH ~6 at temperatures above 10 °C). The measured sarcomeres (1.98 - 2.12 μm) confirmed that cold shortening did not occur under slaughter conditions set for this study. The average muscle ultimate pH values were ~5.8, with no significant differences between the two goat breeds or carcass treatments. The LD samples of delayed chilling treatment recorded higher instrumental colour values than corresponding samples of electrical stimulation treatment. The LD samples of electrical stimulation had higher evaporative losses (20.5 ± 0.93% vs. 17.9 ± 0.65%) and total cooking losses (20.9 ± 0.97% vs. 18.2 ± 0.65%) than corresponding samples of delayed chilling treatment. The WBSF values of the LD samples (4.03 - 4.53 kg) were not different (P >0.05) between the two goat breeds or carcass treatments. There were no significant differences between the two treatments in instrumental colour, surface myoglobin pigments or moisture parameters of the SM samples. Electrical stimulation was effective in improving the tenderness of the SM samples, particularly in Boer goats. This study showed that both indigenous and Boer goats can yield meat with acceptable objective properties, if appropriate slaughter conditions are practised.Thesis (PhD)--University of Pretoria, 2017.National Research Foundation (NRF)Animal and Wildlife SciencesPhDUnrestricte

Effects of palm oil supplementation and fibrolytic enzymes in high forage diets on growth, carcass characteristics and fatty acid profiles of lambs

This study investigated the effects of palm oil and fibrolytic enzyme supplementation in high forage diets on growth, carcass characteristics and fatty acid composition of lambs. Forty South African Mutton Merino ram lambs were randomly assigned to four treatment groups (n = 10 lambs/ treatment) and fed a basal total mixed ration (TMR). The treatments were: TMR diet with Megalac as bypass oil (control); TMR diet supplemented with 3% palm oil; TMR diet with cellulase and xylanase enzymes and TMR diet supplemented with 3% palm oil and cellulase and xylanase enzymes. The lambs were slaughtered at a target weight of about 42 kg. Palm oil supplementation resulted in a longer feeding period (P < 0.05) and lower dressing percentage (P < 0.01), but the carcasses had higher meat yield (P < 0.01) and lower fat content (P < 0.05) compared to the other treatment groups. Additionally, palm oil supplementation increased the proportion of C18:0 (P < 0.05) while decreasing (P < 0.05) the proportion of C14:0 (P < 0.05) and C16:0 (P < 0.05) in fat depots, which may be beneficial for human health. The fibrolytic enzyme treatment had minimal effects on growth, carcass characteristics, meat quality and fatty acid composition of lambs. The interaction effect of palm oil and fibrolytic enzymes had positive effects on the UFA: SFA ratio due to an increase (P < 0.05) in C20:3n6 and C20:4n6 and a reduction (P < 0.05) in saturated fatty acids. The results suggest that methane mitigation strategies through palm oil and enzyme supplementation can be used in lamb diets without adverse effects on product quality.International Atomic Energy Agencyhttps://www.elsevier.com/locate/smallrumres2023-03-02hj2022Animal and Wildlife Science