Production in vitro embryo of donors prepubertal Hostein

Abstract

The in vitro embryo production in dairy cows of high production (Bos taurus) has low efficiency. In this context, the use of heifers as oocyte donors could be an alternative to improve the efficiency of this biotechnology. With the employment of this tool it is possible to enhance in vitro embryo production associated with increased genetic gain by reducing the generation interval in herds of high milk production. However, there is paucity of literature data on the in vitro production of embryos derived from young donors, which motivates the realization of this research project. One hundred and twenty four different categories of donors (heifer prepubertal, n = 30; pubertal heifers, n = 30; lactating cow, n = 30 and non-lactating cows, n = 30) will be subjected to follicular aspiration (Ovum pick-up ). Be assessed number of follicles, total recovered structures and the number of viable oocytes. The viable oocytes are referred for in vitro production of embryos and embryonic development (cleavage rate and blastocyst) will be evaluated. It will be used one delivery of semen for fertilization of the oocytes of all categories. Embryos produced will be transferred to recipients crossbred (Bos taurus x Bos indicus). Statistical analysis will be performed using SAS statistical procedure GLIMMIX. Will be considered as fixed effects the animal category (heifers prepubescent and pubescent and lactating cows and non-lactating), the intake session (number of sessions) as well as their interaction. The effect of individual donor within each session suction is considered as a random effect in the statistical model. The variables included in the statistical model will be sequentially removed following the statistical criterion of Wald (AU)