Breed differences in body composition of equally mature sheep

Abstract

SUMMARY Sheep from the Soay, Finnish Landrace, Southdown and Oxford Down breeds were serially slaughtered at about 40, 50, 60 and 70% of their estimated mature body weight. Breed and sex comparisons were made at these degrees of maturity. Large differences were found in the weight of muscle, fat and bone, total muscle ranging from a mean of 3·3 kg in the Soay to 13·0 kg in the Oxford Down; the corresponding range for dissected fat was 1·2 to 9·2 kg. Most of the breed and sex differences observed at the same degree of maturity disappeared when expressed as a percentage of body or carcass weight. Thus both sexes had almost the same body and carcass composition in terms of fat, muscle and bone percentage. There were breed differences in fat percentage, with the Soay significantly less fat than the other breeds. Total muscle as a percentage of body weight was remarkably close to 28·5% in all breeds in both sexes, and at all four stages of maturity.