e 65,7% (44 das 67 receptoras tratadas com rbST). As concentrações séricas de progesterona obtidas nas amostras de sangue coletadas no dia da inovulação não diferiram com a administração de rbST: 2,54 ± 0,19 ng/mL (sem rbST) e 2,27 ± 0,20 ng/mL (com rbST). Esses resultados indicam que a administração de 500 mg de rbST no dia do estro aumenta a taxa de gestação, mas não influencia a concentração sérica de progesterona de receptoras de embriões recém-colhidos. Palavras-chave: progesterona, taxa de gestação Inovulation of bovine embryos recently collected in receiving treated with rbST in the estrus dayABSTRACT -This study aimed to analyze the effects of rbST administration in the estrous day, on pregnancy rate and progesterone concentration in cows embryo receivers. The subcutaneously administration of rbST (500 mg) was done in 67 receivers, and 77 without the rbST administration (144 receivers totally). The pregnancy determination was done 30 days after the estrous day and the pregnancy rate was different between the treatments where: 32.5% (25 from 77 without rbST administration) and 65.7% (44 from 67 receivers treated with rbST). The serum progesterone concentration from the blood samples collected on the embryo transfer day were not different in presence of rbST treatment: 2.54 ± 0.19 ng/mL (without rbST) and 2.27 ± 0.20 ng/mL (rbST). In brief, these results suggests that 500 mg of rbST administration on the estrous day increase the pregnancy rate, however it does not have influence on serum progesterone concentration in cows receiver of fresh embryos.

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