Effect of cryopreservation of in vitro produced embryos on pregnancy rate of cows transferred at fixed time in the dry tropics

Resumen

The objective of this study was to determine the effect of cryopreservation (CP) of in vitro produced embryos (EIV) on the pregnancy rate (PR) of cows transferred at fixed time (FTET) in the dry tropics. The experimental design was completely randomized with a 2×2 factorial arrangement. The sample consisted of 280 embryos produced in vitro. The factors were the CP (vitrified and fresh) and the Rural Development District (DDR 01 and 02). The experiment consisted of 70 replicates per treatment: T1) fresh transferred embryos; T2) vitrified embryos; T3) DDR + fresh embryos; and 4) DDR + vitrified embryos. The pregnancy diagnosis was carried out 60 days after embryo transfer. The Xi² test was used to analyze PR which was the response variable per treatment. PR was higher in fresh-transferred embryos than in vitrified embryos (53.6±4.2 vs 27.1±3.7; P<0.05), and in DDR02 than in DDR01 (47.1±4.2 vs 33.6±3.9; P<0.05). Therefore, the transfer of fresh embryos and the DDR02 had a positive overall effect on PR (40.3%).