Current state of horse embryo transfer technology in Russia and factors influencing its effectiveness

Abstract

The article presents data on activity in the field of embryo transfer in the Russian horse breeding system and analyzes of the factors influencing the success of the use of this technology. The results of Russian reproductive specialists work over the past 15 years have been collected (144 procedures of embryo recovery in 52 mares). The influence of age and degree of synchronization of ovulations between donors and recipients on the level of embryo recovery and survival rates was analyzed. It has been established that the highest embryo recovery rate is observed in mares of 2- 10 years old (yo) - 84.6%. In mares of 11-16 yo, this figure decreased to 64.3% (p˂ 0.05), and for 17-24 yo mares - to 42.8% (p˂ 0.001). The survival rate of embryos in the uterus of recipient mares of 3-14 yo remains at 70- 71%, in mares of 15-20 yo it sharply decreased to 42.8%. It has been shown that embryo transfer to a recipient whose ovulation occurred 1 day earlier or within a period of up to 5 days after the donor's ovulation provides a survival rate of 79% until the 35th day of pregnancy. When the recipient ovulation occurs 2-4 days earlier than the donor ovulation, the result of embryo transfer was dramatically reduced (7 ,7±7,4%, p˂0.001).