PROPORÇÃO DO SEXO NA PRODUÇÃO IN VITRO DE EMBRIÕES BOVINOS

This study aimed to evaluate the sex ratio using sperm from conventional or sexed semen to female in a program of in vitro production of embryos (PIVE) cattle. Oocytes from 87 donors were used Bos taurus indicus Nelore obtained by transvaginal follicular aspiration system guided by ultrasound. The selected oocytes were matured in vitro, fertilized with sperm derived from conventional semen (group 1 - CONV) or female sexed semen (group 2 - SEX) and the embryos were then cultured in vitro for seven days. After cultivation, they were packaged and ovulated on receiving crossbred Bos taurus x Bos taurus indicus. Transferred 1,319 embryos, with 1,081 produced with conventional semen (CONV) and 238 with female sexed semen (SEX). Early pregnancy diagnosis and fetal sexing were performed by transrectal ultrasonography. The overall pregnancy rate was 37.38% (493/1.319) and 37.74% (408/1.081) in CONV group and 35.71% (85/238) in group SEX. The sex ratio was skewed in the CONV group (P=0.002) in favor of males (57.84% male and 42.16% female) and SEX group was a shift in the proportion (P=0.001) in favor of females (68.24% female and 31.76% male). It was concluded that the use of conventional semen in cattle PIVE increased the proportion of males and products despite the use of sexed semen female be an alternative to pre- select the sex of products, although there was a considerable rate of males when using this type of semen.