Abstract

ERRICO, S. et al. Efecto de la gonadotrofina coriónica equina sobre el porcentaje de preñez y pérdidas embrionarias en vacas Braford. Rev. vet. [online]. 2016, vol.27, n.2, pp.121-123. ISSN 1669-6840.

The objective of the present study was to evaluate the effect of equine chorionic gonadotropin (eCG) at withdrawal of a progesterone intravaginal device (PID) and/or 16 days after fixed-time artificial insemination (FTAI) on pregnancy rate and embryo lost rate between days 30 and 55 after FTAI on suckled Braford beef cows of low corporal condition (1.5-2, scale 1-5). Cows (n=162) were randomly distributed to four treatments; group eCG0: on day -8 cows received a PID with 750 mg of progesterone (P4) plus 2 mg of estradiol benzoate (EB). On day 0 PID were removed and cows received 0.150 mg of cloprostenol, 1 mg of estradiol cypionate (ECP) and 400 IU of eCG. Group eCG16: cows received the same treatments than group eCG0, but eCG was administered on day 16. Group eCG0-16: cows received the same treatments than group eCG0, plus another injection of eCG on day 16. Control group: cows received the same treatments than group eCG0, without eCG. FTAI was performed 48-52 h after PID removal. Pregnancy diagnosis was performed by ultrasonography on days 30 and 55 after FTAI. The administration of eCG at PID removal enhanced pregnancy rate on days 30 (49.4 vs. 28.8) and 55 (48.1 vs. 26.3) (p<0.05) and have no effect on pregnancy loses. In conclusion, administration of eCG at the moment of PID removal in suckled beef cows of low corporal condition (1.5-2) increased pregnancy rate at FTAI. Administration of eCG 16 days after FTAI do not affect pregnancy rate; eCG do not affect pregnancy loses.

Keywords : cow; reproduction; eCG; FTAI; corporal condition; pregnancy.

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