Breed and sex differences among equally mature sheep and goats 4. Carcass muscle, fat and bone

Abstract

Males and females from Soay, Welsh Mountain, Southdown, Finnish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and a breed of feral goats were slaughtered when proportionately 0-40, 0-52, 0-64 or 0-76 of mature live weight. On average, carcasses contained 583 g muscle, 243 g fat and 174 g bone per kg. Individual cuts (four commercially higher-valued and six lower-valued cuts of the shoulder, rib, loin and gigot joints) ranged from 375 to 670g muscle, 129 to 625 g fat and 0 to 294 g bone per kg.Allometric coefficients are given for 32 traits. The distribution of bone in the carcass joints changed little as animals matured but carcass muscle and fat distributions changed significantly.Breeds differed significantly in proportion of carcass muscle, fat and bone and also in their distribution. Welsh Mountain, Southdown, Wiltshire and Oxford Down all deposited carcass fat about three times more rapidly than did the Soay, goat, Finnish Landrace and Jacob. The Oxford Down had the lowest proportion of muscle (514 g/kg) and most fat (317 g/kg). The Southdown had least bone (148 g/kg) and the feral goat most muscle (662 g/kg). Southdown and Soay had the most muscle in commercially higher-valued cuts and Jacob and feral goat the least. Males had significantly more of their muscle in the neck and shoulder and significantly less in the gigot and flank.As breed size increased, proportion of carcass muscle and bone decreased and proportion of carcass fat increased. These breed regressions were attributed to the small but exceptionally lean feral Soay and goat breeds, rather than to a failure of genetic size-scaling. There were no significant trends with breed size among the domesticated breeds. t , r t " . u^n a ;" o quantified by allometry and also by the T H E proportion of muscle, fat and bone in a M J . J J u i I » • n •• v slaughtered at four degrees of maturity. c u s ' Changes in proportions of muscle, fat and MATERIAL AND METHODS

Carcass composition comparison of male and female red deer and hybrids with Père David's deer

“…This is similar to studies in sheep where females had a greater proportion of total carcass muscle in the rib/loin area than males (Taylor et al 1989). The comparative distribution of bone and fat in male and female deer reflects the relatively greater proportion of the carcass in the caudal regions.…”

“…This also concurs with the shift in muscle distribution observed in comparisons between castrate and entire deer where castrate forequarter muscle was proportionately 7% lighter and hindquarter muscle was proportionately 7% heavier than in entire males (Tan & Fennessy 1981). Rams have also been shown to have higher proportions of their muscle in the neck and shoulder compared with ewes (Taylor et al 1989).…”

“…In addition, this advertisement is more than appearances, as neck and leg strength play a role in inter-male contests. Although sheep have been domesticated for much longer than deer (still considered as semi-domesticated in New Zealand), rams also deposit a greater proportion of their total fat in the shoulder region and less in the rib/loin regions than ewes (Butler-Hogg & Brown 1986;Taylor et al 1989). In this study the rib/loin bone allometric growth coefficient (b) in males indicated that bone growth in this primal cut was later maturing than in females (M 1.779 versus F 1.128).…”

Growth and carcass composition of lambs of two breeds and their cross grazing ryegrass and clover swards

“…The values for the cross were intermediate but closer to those for the Suffolk. It is unusual to find differences among domestic breeds of sheep in carcass composition at the same degree of maturity (McClelland et al, 1976;Taylor et al, 1989). Butterfield et a/.…”

“…In domestic breeds of sheep, differences in mature size are responsible for much of the variation in carcass composition at a given weight (Taylor et al, 1989). This is true even where breeds have different roles within the sheep industry (Wood et al, 1980).…”