Pre- and postnatal study of the carcass growth of sheep 3. Growth of dissectable and chemical components of muscle, and changes in the muscle: bone ratio

Abstract

ABSTRACTThe half carcasses of 39 pre- and postnatal Romney sheep were dissected into anatomical units of bone and, where possible, into 32 muscle units which comprised nine functional groups. The growth of wet weight of the total bone and of the muscle groups (and their chemical components, which included deoxyribonucleic acid, protein, and total lipid) was compared with the growth of the carcass using allometric analysis.Although bone grew faster prenatally than postnatally relative to carcass weight, the growth of total muscle and of all the muscle groups and their chemical components occurred at a constant, linear rate throughout the growth period studied.The muscle: bone ratio decreased during prenatal growth, reached a minimum at around parturition and then increased postnatally.The abdominal, m. longissimus and thigh muscle groups grew faster than total side muscle, relative to carcass weight.Protein, and especially triglyceride, grew at relative rates which exceeded that of muscle wet weight.The amount and proportion of intramuscular triglyceride, and the weights of the muscle groups in sheep at three different stages of growth, were predicted from allometric equations. The content of triglyceride was greatest in the cutaneous and neck muscle groups. As a proportion of total muscle, the thigh, m. longissimus and abdominal groups increased as carcass weight increased from 1 kg to 15 kg.