Effect of shearing ewes during mid- and late-pregnancy on lambs weight at birth and survival to weaning under grazing conditions in Uruguay

During a three-year period on commercial farms in Uruguay mature ewes and hoggets were either shorn in mid- or late-pregnancy to examine for effects on lamb live weight and survival to weaning. The study included singleton- and twin-bearing ewes and single bearing hoggets and their lambs. Lambs born to mature ewes and hoggets shorn in mid pregnancy were heavier (P < 0.05) at birth than those born from ewes shorn in late pregnancy. The weaning weight of lambs born from twin bearing ewes and single bearing hoggets did not differ between the shearing treatments (P > 0.05). Shearing treatment had an inconsistent effect on the weaning weight of lambs born to singleton bearing ewes. Shearing treatment had no effect on lamb survival to weaning in all groups (P > 0.05). Combined these results suggest there is little scope to increase lamb performance to weaning by shearing ewes and hoggets at mid pregnancy compared to late pregnancy under Uruguayan commercial conditions.