Administración de progesterona de acción prolongada después de la fertilización en ovinos superovulados y su relación con el tamaño de cuerpos lúteos y embriones

Abstract

The effect of short- and long-acting progesterone (P4) in early ovine metaestrous upon the size and number of corpus luteum (CL), progesterone and cortisol concentration, and number of embryos recovery at days 7 and 13 post-artificial insemination (AI) were analyzed. The study was carried out in Irquis livestock farm owned by University of Cuenca with 21 Correidale ewes, which were submitted to estrous synchronization with P4 intravaginal devices and ovary stimulation with equine chorionic gonadotropin (Folligon ®) and follicle-stimulating hormone (Folltropin ®). After estrus, ewes were inseminated and randomized assigned to one of the following treatments: (T1; n=7) control; (T2; n=7) 6 mg of P4 (Progestar ®) on days 2, 3 y 4 post-IA, and (T3; n=7) 18 mg of long-acting P4 (Progesterone MAD-4 ®) on day 2 post-IA. Fecal P4 and cortisol were also assessed on days 2, 3, 4 and 5 post-AI. The size and number of the CL and embryos were performed by mid-ventral laparotomy on days 7 and 13; and also blood samples for P4 concentration determination were collected on day 13. A randomized block design was used to analysis of data. No statistics differences between treatments were found. Also, no embryos were recovered in any experimental group. In conclusion, the short- and long-acting P4 applied in early metaestrous did not affect the size and number of CL, serum P4 concentration, also, did not affect the concentration of P4 and cortisol in feces.