Early weaning of lambs: effect of various preweaning factors on voluntary food intake before and after weaning

Abstract

Fifty-two crossbred lambs were used in four experiments to study the relative importance of such factors as birth weight, sex, age of weaning, provision of extra salt, and restriction of milk intake, on the intake of solid food (pellets) both before and after weaning, and on the growth check after weaning. Experiment I was a 2 x 2 x 2 factorial (sex x birth weight x weaning at 21 or 42 days) with 24 lambs. All lambs were given milk to appetite until they had made an estimated gain of 23 MJ; milk intake then restricted to a maintenance level. Twelve lambs were weaned at 21 days and the remainder were given milk sufficient for maintenance up to 42 days, when the experiment was terminated. Three out of six lambs that weighed less than 2.7 kg at birth died when weaned abruptly off milk at 21 days. Lambs that were heavy at birth (> 3.4 kg) survived weaning at 21 days but had a growth check of 11 ¦ 5 days. Both the heavy and light birth weight lambs that were given a restricted intake of milk daily from 22 to 42 days ate similar amounts of pellets between 22 and 42 days, but less than those eaten by the heavy birth weight lambs weaned at 21 days. There was no effect of sex on pellet intake or on the length of the growth check. In experiment 2 the provision of a block of salt from 10 days of age had no significant effect on pellet intake before or after weaning at 28 days. In experiments 3 and 4 the milk intake of half of the lambs in each experiment was restricted to a maintenance level for 7 days before weaning. In experiment 3 the lambs weighed more than 3.6 kg at birth and were weaned at 21 days. Restriction of milk intake was without effect either on the intake of pellets before and after weaning or on the length of the growth check. In experiment 4 the lambs weighed less than 3.2 kg at birth and were weaned at 35 days. Lambs given a restricted intake of milk from 29 to 35 days ate significantly more pellets both before and after weaning and had a significantly shorter check to growth than lambs given milk to appetite until weaning.