Abstract :
The use of mid prepartum shearing has been described as a possible tool to increase the
weight of the lambs at birth and at weaning. The effect of prepartum shearing (53 days of
gestation) on production and chemical composition of milk, weight of the lambs at birth
and weaning and growth rate were evaluated in this trial. Twenty Polwarth ewes were
inseminated with rams of the same breed in May (autumn), 2009. All ewes bore singletons
and were maintained together under cultivated grazing conditions, during the experimental
period. The ewes were allocated to two treatments groups, based on expected day of
parturition, body weight and BCS of the dams. Ten ewes were shorn at 53 days of gestation
(S53) and 10 ewes were kept unshorn during gestation (US). Milking of the ewes was
recorded 7 days after parturition, and this was repeated weekly for 15 weeks. Milk production
of the S53 ewes was 22.2% higher (P < 0.05), when compared to US control ewes –
with no change in the milk composition. At lambing, the lambs born to the S53 ewes were
1.41 kg (P < 0.05), and at weaning 4.5 kg heavier (P < 0.05), than lambs born to US ewes. In
conclusion, it can be said that the higher weaning weight of the S53 lambs was the result
of both a higher birth weight and an increased growth rate up to weaning in part, due to
an improved milk production of the ewes
