POSTWEANING PERFORMANCE OF ARTIFICIALLY REARED LAMBS WEANED AT 21 VS. 28 DAYS OF AGE UNDER TWO POSTWEANING HOUSING REGIMENS

Lambs that had been artificially reared on either lamb milk replacer or calf milk replacer were weaned at 21 or 28 days of age. At weaning, lambs from each milk replacer were randomly assigned to two treatments: (1) transferred on the day weaned to a growing barn, and (2) retained in their liquid-diet pens to 49 days of age, then transferred. Delaying weaning from 21 to 28 days of age essentially eliminated the postweaning growth check for lambs artificially reared on lamb milk replacer and reduced the postweaning growth check for those reared on calf milk replacer. However, the resulting increase in liveweight at 70 days of age was not sufficient to offset the cost of the milk replacer required for the extra week on liquid diet. Postweaning location had only a minor and inconsistent effect on lamb performance indicating that, when facilities are satisfactory, postweaning location is of minor importance for artificially reared lambs. Key words: Lambs, artificial rearing, weaning age, postweaning location