Influence of sex and year on carcass characteristics important in the marketing of second cross lambs

Abstract

The carcass characteristics important for the marketing of ewe, wether and ram lambs were examined for lambs grazing annual pastures in northeastern Victoria. The lambs were Poll Dorset x (Border Leicester x Merino). The lambs grew on abundant, high quality pastures after a spring lambing in 1983. The climate in 1984 was very dry and the lambs were born in autumn when pasture availability was low, and pasture clover content reduced. Apart from carcass weight and fat depth (GR) which are used in the AUS-MEAT lamb carcass description, it was found that sex also influenced the level of subcutaneous fat; and also the GR measurement and distribution of subcutaneous fat. Sex did not, however, affect primal joint size in a commercially important way. It was concluded that lamb sex should also be included to improve carcass description, and this would be more important as larger carcasses were used. The area of the M. longissimus dorsi at the 12th rib (EMA) was not affected by sex, but it was a significant (Pc0.01) inclusion with carcass weight in predicting hindleg muscle content. Year affected level and distribution of subcutaneous fat, EMA, and primal joint size even after GR and carcass weight were described. However, the major influence of year was not clear, because there were 2 times of lambing in 2 years when nutrition was vastly different.