EFFECTS OF UTERINE LAVAGE FRACTIONS ON EMBRYO RECOVERY RATE IN MANGALARGA MARCHADOR MARES.

Since 1986, the use of embryo transfer has gained prominence in the equine industry, allowing the increase in the number of descendants of genetically superior donors, competition mares, foals, and mares considered subfertile. The success of an embryo transfer program is directly related to the rate of embryonic recovery by mare, which is characterized by the percentage of embryos collected by uterine lavage. However, the recovery rate can be influenced by several factors, type of donor used, age, day of collection, and physical activity. Considering the advancement of biotechnology and the growing need for research in the area of equine embryo transfer, the present work aimed to study in Mangalarga marchador animals the effects of uterine lavage fractions on embryo recovery rates. The present study included 35 mares aged between 3 and 15 years, used as donors of clinically healthy embryos from an equestrian property in the southern region of Rio de Janeiro. Thus, 67 uterine washes were performed, where 67% of the embryos were recovered through different volumes of ringer's solution with sodium lactate. The embryo crops and transfers period was from September 2021 to January 2022. For statistical analysis of the data, the simple logistic regression test was used, where no significant difference (p<0.05) was observed in the embryo indices recovered on total crops (67) regarding fractions (F) 1 (43.2%), (F) 2 (14.9%) and (F) 3 (5.97%). Thefore, it can be concluded that there was no significant difference between the lavage fractions, however, more studies are needed with a larger sample of uterine washing.