Abstract

Twenty eight Border Leicester 2-tooth rams (mean live weight 70 kg) were scored for fatness on a 10-point scale by 6 drafters and back fat thickness was measured by ultrasonic probe (UFD). Chemical fat percentage (mean 33.9%) was determined on a half-carcass of each ram. Mean carcass weight, measurement C and GR were 38.0 kg, 12 mm and 28 mm respectively. Mean drafters' fat score was more highly correlated with % carcass fat (+0.83) than UFD (+0.67). The prediction of fat-free carcass weight (FFCW) from live weight plus UFD (R2=0.72, RDS 1.24 kg) or drafters' fat score (R2=0.76, RSD 1.14 kg) was superior to prediction from live weight alone (R@=0.59, RSD 1.49 kg). The inclusion of UFD o9r drafters' fat score increased the efficiency with which rams were ranked for fat-free carcass weight. Selection of the top 10% of rams ranked on the prediction of FFCW from live weight achieved 75% of the potential selection differential. Inclusion of either UFD or drafters' score improved the potential to 95%.

GL, Bennett, and JN Clarke

Proceedings of the New Zealand Society of Animal Production, Volume 44, , 243-248, 1984