Shearing pregnant ewes to improve lamb birth weight increases milk yield of ewes and lamb weaning weight

Abstract

Milk yield, lamb birth weight and weaning weight responses to shearing during winter in sheep were investigated. A total of 46 Karayaka ewes were allocated into two treatment groups. Pregnant ewes in one group were shorn on day 100 of gestation (Shorn, n=24) and the remaining ewes were left unshorn to serve as controls (Unshorn, n=22). The ewes were maintained on pasture during the day and housed in the evenings. Lamb birth weight, weaning weight and ewes' daily milk yield in fifteen dayintervals until weaning (75 days) were recorded. Shearing ewes on day 100 of pregnancy increased gestation length (p<0.01) compared to unshorn ewes (147.8+/-0.45 vs. 145.9+/-0.42 days). Birth weights of lambs from shorn ewes on day 100 of their pregnancy were higher (p<0.01) than those from unshorn ewes (3.7+/-0.11 vs. 3.2+/-0.07 kg). Shearing pregnant ewes increased (p<0.05) the lamb weaning weight at day 75 post-lambing (23.6+/-1.10 vs. 19.5+/-0.91). It also increased milk yield (p<0.05). Milk yields on day 75 of lactation were 302+/-33 and 425+/-25 g per day for unshorn and shorn ewes on day 100 of pregnancy, respectively. Lamb survival at weaning was higher (p<0.05) in lambs from shorn ewes compared to those from unshorn ewes. In conclusion, shearing pregnant ewes in winter months enhanced milk yield, lamb birth weight, lamb weaning weight and lamb survival. It is suggested that increasing both lamb birth weight and subsequent milk yield of dams by shearing ewes on day 100 of pregnancy during winter may improve postnatal lamb viability.