Increasing lambing perfcrmance of ewes by active immunization with polyandroalbumin

This study was conducted on 110 cross-bred Hisardale x Nali ewes. The ewes were divided into two groups: one group was treated with 2 ml of polyandroalbumin subcutaneously (s.c.) twice at an interval of 28 d, with breeding rams introduced 28 d after the second injection of the drug. The second group served as the untreated controls. Of the 55 ewes in each group, 52 were mated during the 40 d breeding period. The occurance of estrus and estrous cycle length were the same in the two groups. Fortysix ewes in the treated group and 47 ewes in the control group lambed, producing 55 and 47 lambs, respectively. In the treated group, the lambing rate, fecundity and fertility were 100, 96.36 and 88.46%, while these values for the control group were 85.45, 83.64 and 90.38%. Prolificity rates were 1.15 and 0.98 for the treated and control group, respectively.