The effect of shearing pregnant ewes prior to a winter-lambing season on ewe and lamb performance in the southern Cape (Short Co

Author: S.W.P. Cloete, F.E. van Niekerk and G.D. van der Merwe
Year: 1994
Issue: 4
Volume: 24
Page: 140 - 142

About half of the 505 winter-lambing SA Mutton Merino ewes were shorn at four or fewer weeks prior to lambing at the Outeniqua Experimental farm near George in July-August 1991 and 1992. The remaining ewes, with a 6 – 7-month fleece, were only crutched. The reproduction of all these ewes was monitored, while data from 666 progeny were used to investigate the effects of shearing on early lamb growth and lamb survival to weaning. During 1991, shearing prior to lambing improved (P ≤ 0.05) lamb birth mass by 4.9% relative to progeny of the unshorn control group. There was also a tendency (P ≤ 0.08) for shearing to improve lamb survival (0.73 vs. 0.64). During 1992, birth mass and lamb survival of progeny of shorn ewes did not differ from that of progeny of unshorn ewes. Shearing ewes prior to lambing improved (P ≤ 0.01) their lamb daily gain (to eight weeks) by 8%. The productivity of ewes (expressed as mass of lamb weaned/ewe joined) also improved (P ≤ 0.05) by 19% in shorn ewes. The latter result suggests that biological gains may be derived from the shearing of winter-lambing ewes prior to lambing, although effects on lamb birth mass and survival were inconclusive. Since shearing prior to lambing appears to be a cost-effective method of improving the efficiency of winter-lambing ewe flocks, further studies are envisaged.

Keywords: ewe reproduction, lamb growth, lamb survival, shearing prior to lambing
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