无角道塞特羊胚胎移植技术研究

（西北农林科技大学生物工程研究所，陕西杨凌712100）

Effect Factors on Embryo Transfer in Poll Dorset Sheep

The study confirmed the effect of donor and recipient and embryo stage etc on sheep embryo transfer. (1)Poll Dorset (n=163) sheep were treated by superovulation (SOV), the number of embryos was evaluated in virgin ewes (n=76) and in ewes-once delivery (n=87), respectively. The mean number of embryo and useful embryo recovery was significantly higher in virgin ewes than in ewes-once delivery (5.33,3.91 versus 7.55,6.34, P<0.05). SOV efficiency was not significantly different in the spring and in the fall, and repeated-SOV had no significant effect on embryo recovery (P>0.05). (2) Estrus synchronization (ES) rate of recipient (n=876) was 56.37% and 89.02% in the spring and in the fall, utility ratio of recipient was 84.67 % and 88.77%, respectively. (3) 318 recipient pregnancy and 396 lambs were born from total 545 recipients transferred, recipient pregnancy and lambing rates were 58.35% and 57.47% respectively. Among all recipients, small-tail sheep had the highest pregnancy rate (61.2%), the second of pregnancy rate were tong sheep (54.62%) and Mongolia fine-wool sheep (56.58%), No significant differences were observed in different sort of recipient (P>0.05), the corpora lutea number of recipient had some side-effect on pregnancy and lambing rate (although not significantly). the embryo stage also contributed to pregnancy rate, recipient of blastocyst transferred got the highest pregnancy rate (64.76%), significantly higher than that of early morula (P<0.05). There was no significant difference in lambing rate per embryo from the morula stage to blastocyst (P>0.05).