Forty-two crossbred dairy cows or heifers were randomly allocated to two treatments: T1 (n=22) - control group, without hormonal treatment; T2 (n=20) - treated group with buserelin in the fourth day after embryo transfer, to evaluate the effect of hormonal treatment on the pregnancy rate and plasma concentrations of progesterone in bovine embryo recipients. Blood collection samples for plasma obtainment were realized on day of embryo transfer (day 0) and every other day, in a total of five samples per recipients. The pregnancy diagnosis was realized by transrectal way. The use of a GnRH agonist (buserelin) on the fourth day after embryo transfer did not result on difference between treatments in relation to the pregnancy rate. However, the plasma levels of progesterone of pregnant recipients of the treated group were greater as compared with those of the control group.
bovine; buserelin; embryo transfer; progesterone; pregnancy rate
