Sex, age of animal and weight at slaughter as explanatory variables for carcass and meat quality properties in goats and sheep production

Abstract

Slaughtering kids/lambs at specified age and weight of specialized goat and sheep meat breeds might promote high muscle deposition and a desirable carcass fat cover, culminating into meat with a more adequate nutritional profile and health properties for human consumption. In this case, animal factors such as sex, age and weight at slaughter play a central role as the primary explanatory variables on meat yield and quality of carcass parameters in goat and sheep production. The discussion on determinants of carcass and meat quality properties is complex given that the diversity of goat and sheep meat breeds, both early and late maturing is considerable, over and above exploited as is the practice in non-identical production systems. Of interest goats and sheep in most cases are accordingly slaughtered at different weights and age, and on the other hand, specific markets have preferred sex of animal for slaughter. However, taking cognisance of the above, carcass and meat parameters are influenced by various non-genetic effects, hence the knowledge on these factors and their interactions becomes of paramount importance in order to produce desirable meat quality for specified markets and consumers’ preference. A linear relationship between carcass yield with age at slaughter has been reported in goats and sheep, there is a tendency of carcass weight increasing as the age of the animal increases. Sex dependency on carcass and meat parameters has been inconsistent in goats and sheep, however, most studies show that sex greatly influence carcass and meat quality properties. Compromised dressing percentage in goats and sheep due to higher slaughter weight, could be explained by the lightest animals lacking perfectly developed digestive tracts. Against this background, age at slaughter explicitly influences meat quality, particularly with regards to tenderness of meat derived from young animals. The differential carcass status in young and mature animals is due to increased fat deposition in older animals than in younger ones, while fat tissue increases with increased slaughter weights. Complexity of determination of desirable carcass and meat parameters is ascribable to interaction of many variables, hence it is imperative to appreciate the role of each component by appropriately factoring their influence in any slaughter decision, where animals could be slaughtered at given age and weight to meet specified objectives of a particular market requirements. Producers operating in different production systems might not duplicate factors such as age, weight and sex of slaughter because they utilise different genotypes, and the prescribed nutritional regime in non-identical production systems will weigh heavily on the outcome of carcass and meat parameters. The interaction of all these factors (genotype and non-genetic factors) at different levels as influenced by the market expectations will decide the economics of goat and sheep meat production. This present review will give an insight on some non-genetic effects that influence carcass and meat quality properties namely sex, age and weight at slaughter.