Factors affecting the pregnancy rate of embryo recipient IVP: literature review

Abstract

In the last decades, Brazilian livestock farming has undergone great expansion, based not only on quantitative growth, but also on quality. The qualitative growth is based on factors derived from the use of reproductive biotechniques, such as the In Vitro Embryo Production (IVEP), which allows significant genetic advancement in the herd in a reduced period of time, by the multiplication of the genetics of higher animals. For implantation of IVEP, with efficiency and viable cost, it is necessary to consider some factors, as well as the interaction with the gestation rate. The objective of this review was to report the main factors involved in the gestation rate of embryo receptors produced in vitro (IVP), such as corpus luteum quality, donor and recipient synchrony, donor breed, embryo development and quality, reproductive and semen effects, thermal stress, period of the year and number of previous ETs in the recipient. Although the IVEP is an important tool for the genetic improvement of the bovine herd, it is necessary to consider the variations in the results of gestation after its use, mainly with regard to donors and recipients, geographic region, environmental conditions, sanitary and nutritional management of animals, as well as the conditions inherent in the IVP laboratory. The observation of these factors, as well as the constant search for improvements, are fundamental conditions for the success, viability and economic return of IVEP.