Efficiency of wool and body growth in pen-fed Romney, Coopworth, Perendale, and Corriedale sheep

摘要

Abstract Ten 1-year-old sheep of each of the breeds were pen-fed a pelleted diet of 60:40 maize: lucerne at 30, 40, 50, 60, or 70 g/kg initial live weight0·75 /day for 21 weeks divided into 3 equal periods. Intake, wool growth, and body growth were considered relative to body weight0·75 to allow for the effect of between-breed differences in body size. Estimates of the conversion of dry matter (DM) intake/body weighto.75 to body weight gain/body weight0·75 did not differ between breeds or periods. On a pooled within-breed, within-period basis, wool growth/ body weight0·75 (r = 0.69) and fibre diameter (r = 0.69) were correlated with DM intake/body weight0·75. During the last 2 periods the sulphur content of the fleece was correlated within breeds (r = 0.62) with DM intake/body weighto0·75. Fibre diameter (r = 0.76) and sulphur content of the fleece (r = 0.62) were correlated with wool growth/body weight0·75. The regression coefficient for the regression of clean wool/body weight0·75 on DM intake/body weig...