豫西脂尾羊排卵规律及胚胎生长发育规律的研究

豫西脂尾羊以单侧卵巢排卵为主，单侧卵巢排卵母羊百分比为98．18％，其中左侧为34．35％，右侧为63．64％。右侧卵巢排卵母羊数极显著多于左侧卵巢排卵的母羊数（P＜0．01）。总排卵率及排单卵、双卵和三卵的百分率分别为110．91％、90．91％、7．27％和1．82％。其胚胎长度增长以胎儿中期生长速度最快，而体重增长自进入胎儿中期以后一直比较旺盛。研究结果表明，豫西脂尾羊产羔率低的直接原因是排卵率低，主要是排双卵和三卵的比例低。根据豫西脂尾羊排卵及胚胎生长发育特点，就如何提高其繁殖率问题提出了具体建议和措施。

Studies on the Law for Ovulation and Embryo Development in Yuxi Short Thick Dock Sheep

The ovulation from single ovary is in the majority in Yuxi short thick dock sheep,the percentage of the sheep with ovulation from either ovary is 98. 18 %, including 34. 55 % in left and 63. 64% in right. The obvious difference for the ovulation rate exists between left and right ovary (P<0.01 ). The total ovulation rate is 110. 91 %, the percentage of one-egg,twin-egg and three-egg is 90. 91 %, 7. 27 % and 1. 82 %, respectively. The rapid increasc phase in embryo length is medium-period in course of fetus development,while,the inrease in embryo weight is always strong from fetus medium-period to biith date. This study reveal that the reason for the low lambing percetage is a still lower rate for twin-egg and three-egg. According to the character of the ovulation and embryo development in Yuxi Short Thick Dock Sheep,several specific proposals and measures for increasing the sheep fertility have been put forward.