Lactation performance of ewes and the growth of lambs, in Awassi sheep, under two different suckling regimes

Summary The present study was carried out on 39 local Awassi ewes. After parturition, lambs were left to suckle their dams for the first month of age, after which they were separated into two suckling regimes, restricted and continuous. The average milk yield of ewes in the continuous system was 155·7 kg during the lactation period of 167±6·1 days whereas that of the restricted system was 139·8 kg during a lactation period of 183 ± 5·7 days. However, differences were not significant. Significant differences (P < 0·01), in favour of the continuous system, occurred in the amount of milk suckled by lambs in the different suckling systems from the 8th week onwards till weaning. Measured hand milk showed no significant differences between the two regimes. Averages of butter fat percentages were 5·63 and 6·69 in the continuous and restricted systems respectively. The total percentage suckled milk, regardless of suckling regime, was 36·7 ± 1·99; averages were 41·6 ± 0·89 and 31·7 ± 3·52 in the continuous and restricted systems respectively. The averages of commercial milk production from the 9th week after lambing until the end of lactation were 45·9 and 61·7 kg in the continuous and restricted systems respectively (P < 0·01). Averages of butter fat quantities in the commercial milk yield were 3·25 and 5·03 kg in the continuous and restricted systems respectively (P < 0·01). The weights of lambs in the two suckling regimes started to differ significantly from the 14th to the 46th week of age; lambs reared under the continuous system were 4 kg heavier at the yearling age than those of the restricted system. It might be worth considering weaning and selling extra lambs at 3 months of age to make full use of the high growth rate encountered in this period. The breeder could also obtain 11·4 kg more milk from ewes from 9 to 17 weeks after lambing in the restricted system than those in the continuous one. It might be advisable to use the restricted system and wean the lambs at 12 weeks of age; the excess milk obtained will outweigh the extra gain in body weight of 1·52 kg encountered in the continuous system.