The effect of sustained lactation on intake of solid food and growth rate of lambs

Abstract

Summary: An experiment was designed to investigate the effect of a sustained lactation pattern on the intake of milk or solid food by lambs and on their consequent growth rate. Normal lactation pattern was compared with sustained lactation, achieved by fostering lambs at 24 days of age on to newly-lambed nurse ewes. Two genotypes of lamb were used; these were pure-bred Scottish Blackface and Textel × Blackface. Lambs were offered one of two qualities of pelleted concentrate food from 4 weeks of age.Maximum daily intakes of milk were 2·16 and 1·87 kg/day, respectively, for fostered and non-fostered lambs. This differential was maintained until the 10th week. Pattern of lactation had no significant effect on total energy intake from milk and solid food combined or on live-weight gain up to 10 weeks of age. Texel cross lambs consumed more food than did pure Blackface lambs and showed correspondingly higher rates of live-weight gain. Lambs ate slightly more of the higher quality pellets than the lower but there was no effect of solid food quality on milk intake. Within breed of lamb there was a negative relationship between intake of milk and of solid food.