@conference {40324,
	title = {The effect of cow age and management of winter liveweight gain, liveweight at calving and subsequent effects on dairy production in a seasonal supply herd},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {277-282},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A trial was undertaken in which 11 meat company lamb drafters  estimated the GR carcass fatness, hot carcass weight and carcass class  on 26 live lambs. In addition the Phillips Fat Displacement Meter (PFDM)  was used to estimate GR fatness these live animals. The average hot  carcass weight of the lambs was 21.9kg and mean GR on the left and right  sides were 14.2mm and 14.5mm respectively. The best two drafter  estimates correlated more highly (0.89 and 0.83) than the PFDM (0.81)  with lamb carcass GR (mm) on the left sides of these carcasses. On the  right sides these two drafters correlations were respectively 0.91 and  0.84 while the PFDM correlation was 0.85. The correlations of the  poorest drafter were 0.62 and 0.57 for the left and right sides,  respectively. While the best drafters were accurate in ranking live  lambs for fatness, in absolute terms all drafters underestimated GR on  average by 2.2mm whereas the PFDM underestimated by 1.1mm on the left  side and 0.8mm on the right. So for actually drafting lambs for  slaughter, the PFDM is less likely to select lambs in the penalty  payment ranges, or is more likely to select lambs before they reach  these penalty fatness levels than the company drafters. These results  highlight the need for drafter training courses with feedback on their  results. On average the drafters underestimated carcass weight by  4.0kg.  },
	issn = {1176-5283},
	author = {Thomson NA and Barnes ML and Prestidge R}
}
