Breed and sex differences among equally mature sheep and goats 5. Lipid in dry tissue

Abstract

ABSTRACTMales 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. Lipid concentrations in dried tissue were obtained for perirenal fat, omental plus mesenteric fat, subcutaneous fat, carcass muscle plus associated intermuscular fat, carcass bone and offal (pelt, head, feet and organs). Lipid varied from 260 g/kg dry matter (DM) for bone to 968 g/kg for perirenal fat.As animals matured, lipid concentration increased in the dry matter of all tissues except bone, most rapidly in offal and least in intra-abdominal fat. The increases were highly correlated with the associated increases in proportion of dissected fat.Breeds differed significantly in lipid concentration in the DM of all tissues examined. Breeds with a high lipid concentration in DM of one tissue usually had high concentrations in all other tissues. The Oxford Down had the highest concentration, and the Soay and feral goat the lowest. Males had slightly lower concentrations in all tissues except internal fat.As breed size increased, mean lipid concentration (at the same stage of maturity) also increased in the DM of all tissues except bone. These breed regressions were attributed to the sampling of breeds, the smallest breeds being the exceptionally lean Soay and feral goat. Among the domesticated breeds, there were no signficant trends with breed size.