The efficiency of conversion of feed to wool during limited and unlimited feeding of flocks selected on clean fleece weight

Abstract

The wool growth of rams from the Trangie Fleece Plus, Random, and Fleece Minus selection flocks was measured during periods of limited and unlimited feeding in pens. There were large positive genetic and phenotypic correlations between net efficiency (measured during limited feeding) and both wool growth and gross efficiency (measured during unlimited feeding). Net efficiency was phenotypically correlated with voluntary intake of feed. Gross efficiency accounted for 95 per cent of the genetic and 62 per cent of the phenotypic variation in wool growth. The change from limited to unlimited feeding produced genotype x environment interactions with fibre cross sectional area, rate of wool growth and efficiency of conversion, the superiority of the high producing flock being relatively greater during unlimited feeding.