Artificial rearing as a system for evaluating male lambs

Abstract

ABSTRACTThe use of an artificial rearing system to provide controlled environment conditions for performance testing of male lambs was investigated in two trials. A sample of lambs from 5 fat-lamb sire breeds was included.Performance during the initial restricted milk-feeding period was uniform but large differences in solid food intake gave variable performance in the adjustment period immediately following weaning. Lambs were evaluated from 40 days onwards in terms of growth rate and efficiency of food conversion. Some breed differences were significant and the variation within groups was sufficiently high to suggest that performance might be improved by within-group selection.Estimates from Trial 2 show that food conversion efficiency was related to growth rate, but early and late performance in the evaluation period were not correlated (r = 0·12, 0·16 and 0·14 for growth rate, food intake and efficiency, respectively). Some refinements of the method are suggested, and it is concluded that the system could provide suitable conditions for testing male lambs at an early age without the variable influence of the dam.