Genetic and non-genetic influences on growth and carcass traits of goats

Abstract

Compared to sheep and cattle, knowledge of yield and quality of goatmeat is limited. Mature size of goats can vary ten-fold between breeds, with consequent variations in growth rates. Non-genetic factors include maturity, physiological state, nutrition, sex and birth rank. Roles of nutrition and stage of maturity in determining level and distribution of fat are poorly understood. Many effects of maturity and sex on carcass characteristics of goats are similar to those observed in sheep. Does contain less bone in their carcass than bucks, and yield more edible tissue at the same carcass weight. However, due to a greater tendency to deposit fat, females contain less muscle than males at most weights. Mature goats can contain 30% carcass fat or more, but this is unusual, and goat carcasses normally contain lower levels of total fat and less subcutaneous fat than sheep. Goat carcasses contain a higher proportion of total muscle, but its distribution into higher valued carcass regions is less favourable than in sheep. Reported differences in meat tenderness between sheep and goats probably reflect unsuitable pre-/post-slaughter handling of goats more than intrinsic differences between two species. Level of intake and diet composition influence goat carcass composition. High energy feeds can increase fat deposition, but knowledge on this topic is limited. Little is known about effects of feeding and age on meat sensory characteristics such as texture, tenderness and juiciness. There is a huge number of goat breeds in the world, but few objective, comparative data exist. Comparisons are confounded by the range of environmental conditions in which goats are kept. European dairy breeds and the improved Boer goat of South Africa appear to be the fastest growing. Boer goats may have a higher proportion of muscle in the carcass than other goat breeds, but data on this point are far from conclusive.