Fatores que afetam a perda de gestação de embriões in vitro transferidos para receptoras leiteiras mestiças

Abstract

Reproductive efficiency influences production, return rate and genetic improvement. Although there are few properties that use reproduction biotechnologies, they have already proven to improve the reproductive efficiency of the herd. Approximately 80% of national milk production comes from crossbred cows (crossbreeds of European origin specialized in milk production, such as Holstein, Jersey and Swiss Brown, and Indian zebu cows, such as Gir, Guzerá and Nellore). Thus, even with genetic improvement, nutrition, management, and reproduction biotechnologies, it is of no use if there are failures or large pregnancy losses. Since, when the animal loses a pregnancy, genetics, time, and resources are lost. The study used a database from a commercial dairy farm in the region of Monte Alegre de Minas-MG, a descriptive analysis of the data was carried out, regarding the effect of the recipient category (cow vs. heifer) and the stage of development of the embryo (blastocyst vs. expanded blastocyst) on P/ET (pregnancy/ embryo transfer) and loss up to 210 days of gestation. The category of the recipient did not influence the pregnancy loss of embryos produced in vitro, and the total loss of heifers was 15% and cows 16.67%. Expanded blastocysts result in a higher pregnancy rate (50.75%) and lower pregnancy loss rate (11.76%) relative to blastocysts (P/ET 45.45% and total pregnancy loss 30%). Recipient category does not influence pregnancy loss of in vitro embryo production products, however expanded blastocysts result in a higher pregnancy rate and lower pregnancy loss rate.