Abstract :
An experiment was conducted to examine the changes in colostral production and composition in Karakul ewes fed at different
nutritional levels. Pregnant ewes were randomly allotted to one of four groups (n = 20 per group) 90 days after artificial insemination.
Three groups were fed with total mixed rations supplying 90, 100 and 110% of the NRC requirements, respectively, and the last
group served as the control feeding on natural vegetations until parturition. Blood samples were taken from the jugular vein during
late pregnancy, and soon after lambing. Fifteen singleton ewes from each group were hand-milked completely at 1, 12 and 24 h
post-lambing. Samples of colostrum were obtained and the lambs were fed with their ewe’s colostrum (30 g/kg BW) at each milking.
Blood samples were taken from the lambs before receiving their first colostrum, and again at 24 and 48 h post-lambing. Ewes on
110% NRC diet produced significantly (P < 0.01) more colostrum than did the ewes in other groups. Feeding level did not have a
significant effect on the IgG level of the colostrums and blood sera of ewes and lambs. Mean IgG concentration in the ewe serum was
greatest during late gestation (1–2 months before lambing) and were significantly reduced at 1 h post-lambing. Non-immunoglobulin
composition of colostrum was not significantly affected by the treatment. There was a significant correlation between IgG levels
of the ewe serum and colostrum (r = 0.64, P < 0.0001). Mean weight of the ewes on the control ration at lambing and the mean
birth weight of their lambs were significantly lower as compared with other dietary groups. The results suggested that hand-feeding
of Karakul ewes on poor rangeland vegetation with 110% NRC for 2 months before parturition increased colostral production,
decreased the ewe loss and increased lamb birth weight which is beneficial to lamb survival.
© 2007 Elsevier B.V. All rights reserved.
Keywords :
feeding , Ewe , lamb , Colostrum , immunoglobulin
