1. An experiment to test the effects on growth rate of lambs to 15 kg live weight of 5, 7 or 9 kg of milk replacer powder given according to four systems of daily restriction is described and the results are discussed.

2. Although the average age at weaning varied from 18 to 50 days according to treatment, the quantity of milk replacer did not affect the lambs' overall growth rate. Lambs deprived of milk consumed extra concentrates at a rate of 1·75 ± 0·219 kg per kg of milk powder.

3. Although severe restriction of the daily allowance markedly reduced the growth of lambs during the milk-feeding period, they subsequently grew at a faster rate and there was no resultant major depression of overall growth rate. The lambs first consumed a measurable quantity of solid food when they were on average 21 days old and this varied little according to treatment.

4. It is concluded that under the conditions of this experiment it was not economic to give more than 5 kg of milk powder and that it was not advantageous to adopt distribution systems that delayed weaning much beyond 20 days.

5. The applicability of these findings to practice is discussed in relation to the possibility of treatment effects from the rearing period being carried over to the period beyond 15 kg live weight, and also to the possible effects of single penning versus grouping on lamb behaviour.