Effect of weaning system on lamb growth and commercial milk production of Awassi dairy sheep

Abstract

To determine the effect of weaning system on Awassi sheep milk production and lamb growth, 68 Awassi ewes and their lambs (n = 104) were assigned to one of the following treatment groups a) after 3 days from birth (MIX), ewes were separated from their lambs during the evening for 15 h and milked once daily in the morning, and their lambs were allowed to suckle for 9 h during the day or b) ewes were not milked and suckled by their lambs (DY60) during the first 60 days of lactation. Ewes and their lambs were assigned to the groups according to ewe's age, parturition date, sex of the lamb and birth type. All lambs were weaned at 60 days of age and the ewes were milked twice daily. Milk yield was recorded fortnightly and milk fat composition was recorded monthly. The birth weight of lambs was recorded in the first 2 hours and they were weighed fortnightly until 240 days of age. Average lactation lengths (including suckling and milking) in MIX and DY60 group were similar (171.21 +/- 5.40 and 168.36 +/- 4.87 days, respectively). Differences between MIX and DY60 group in commercial milk yield (103.25 +/- 7.93 and 63.59 +/- 5.41 kg, respectively) and milk fat yield (5.88 +/- 0.64 and 3.62 +/- 0.31 kg, respectively) were highly significant (P < 0.001). Growth performance of lambs was similar in both groups (P > 0.05), however, male lambs were heavier and grew faster than female lambs until weaning (P < 0.05) and 90 days of age (P < 0.001). The effect of birth type at 210 days of age for the female lambs in MIX group was found to be statistically significant (P < 0.05) and the mean weight of single born female lambs was 40.39 +/- 1.27 kg, and 41.09 +/- 1.22 kg for twin born female lambs. The effects of ewe's age for female lambs in MIX and DY60 group and birth type for the lambs in DY60 group were insignificant (P > 0.05). These results show that Awassi lambs can be successfully reared in MIX suckling system and ewes produce more commercial milk than in the traditional rearing system (DY60), which offers a potential increase in economic return for Awassi sheep producers.