Changes in body composition relative to weight and maturity of Australian Dorset Horn rams and wethers. 1. Carcass muscle, fat and bone and body organs

Abstract

ABSTRACTMaturing patterns of carcass muscle, fat and bone and of body organs were established relative to live weight, using data from 20 Dorset Horn rams and 20 Dorset Horn wethers. The sheep were fed a pelleted ration from soon after weaning and individual sheep of both groups slaughtered at 6-kg increments in live weight from 18 kg to maturity at approx. 100 and 96 kg for the rams and wethers, respectively. This small difference in mature weight was mostly due to the weight of the testes and the increased weight of the head in mature rams.As proportions of live weight, the mature rams had more carcass muscle and bone and less carcass fat than the mature wethers. In the mature animals the body organs in general comprised similar proportions of live weight in the two groups. However the head, hide and blood were proportionately heavier in the mature rams. The liver and alimentary tract were heavier in the mature wethers.The maturing patterns for the three carcass tissues were not different for the two groups. However, many of the body organs matured on different patterns in the rams and wethers.As the mature live weights and the maturing patterns for carcass tissues and some body organs were not different for the two groups, comparisons of the proportions of these tissues in rams and wethers would yield similar conclusions on an equal weight basis, as on the basis of the same proportion of maturity. However, comparisons of the proportions comprised by some body organs need to take account of different maturing patterns, as comparisons at different stages of maturity will each give different answers.