Body weight change, milk production and reproductive parameters in suckled vs. non-suckled awassi ewes

Abstract

The objective of this study was to identify the effect of early weaning on body weight change, milk production and the return to estrus in Awassi ewes. Twenty multiparous winter-lambing Awassi ewes were randomly assigned to either suckled (S, n=10) or non-suckled (NS, n=10) groups in a completely randomized design. Lambs in the NS group were removed from their dams on day 2 postpartum (PP). Animal body weights (BW) and body condition scores (BCS) were recorded at the beginning of the study and every 3 weeks thereafter until the end of the experiment. Milk production was estimated by machine milking at weekly intervals for 4 weeks beginning on d 11 PP. Blood samples were collected from each ewe every third day for 4 weeks beginning on day 15 PP. Initial body weight was similar for both treatments. By the end of the experiment, NS ewes gained an average of 1.8±1.0 kg while S ewes lost an average of 7.0±1.0 kg (p<0.001). Body condition scores followed a trend similar to that observed for BW and was greater (p<0.001) in the NS ewes. Significant correlation existed (p<0.01) between BW and BCS (r=0.77). The first milk production recording for both suckled and non-suckled was similar. Later recordings, however, showed that the S group had greater milk production (p<0.01) compared with the NS group. Lambs in the NS group were heavier (p<0.05) than those in the S group on d 10 PP. By the end of the study, lamb weights in the NS group were significantly lower (p<0.001) when compared with S group. The first rise in plasma progesterone (P4) occurred earlier (p<0.05) in the NS than S ewes (day 27.0±2.2 vs. 34.0±2.2 postpartum, respectively). All of the NS ewes (10/10) and 60% (6/10) of the S ewes expressed estrus following ram introduction (p<0.05). Results of the current study indicate that non-suckled ewes gained more weight and displayed ovarian activity earlier than suckled ewes. Early lamb removal can be used to obtain biannual lambing in Awassi sheep.