Indutores de ovulação em protocolos de manipulação de ciclo estral ovino

Abstract

Estrus synchronization is a biotechnology used to increase productivity, allowing the FTAI to be performed. Progestogens and eCG are used to provide adequate synchronization of ovulation, but there is increasing pressure from public opinion to reduce the production of eCG. As an alternative to eCG, in sheep, estradiol and synthetic GnRH analog were tested as an ovulation inducer. The objective was to determine the rate of follicular growth and ovulation with the application of eCG, estradiol benzoate and estradiol cypionate, before FTAI and to evaluate the effect of FSH inside and outside the reproductive season. In experimente 1 the sheep (n = 22) received MAP and cloprostenol at removal. They were divided into four groups (CN; n = 5), (CP; n = 5), (CE, n = 6) and (BE, n = 6). In experiment 2, study 1 (out-of-the season, n = 28) remained with Primer-PR for seven days. The animals were divided into four Control groups, eCG, FSH10 and FSH15. In study 2 (out-of-the season, n = 25) they remained with Primer-PR for 14 days and divided into treatments equal to that of study 1. In study 3 (in-season, n = 147), they remained with Primer-PR for 14 days. Divided into three groups: Control, eCG and FSH10. Experiment 3 was performed at the counter station, n = 27 were divided into 3 groups: eCG (n = 8), BE (N = 9) and GnRH (n = 10). It was not possible to observe the effect of FSH and eCG on the manifestation of estrus (P4-14D) outside the reproductive season, the use of gonadotropins increased the rate of follicular growth outside the season, and only eCG was able to induce ovulation. In another study, initially all sheep (n = 115) had estrus synchronized through MAP, at the time of removal they received 300UI of eCG and FTAI1 was performed 48 hours after removal. The use of GnRH in a resynchronization protocol was evaluated, determining the rates of estrus and pregnancy manifestation. Based on the hypothesis of the possibility of new insemination (FTAI2) without determining whether or not the females were pregnant after FTAI1. The animals were divided into two groups, control (n = 59) and GnRH (n = 56). The application of GnRH was not efficient in inducing ovulation in the sheep resynchronization protocol.During the reproductive season, the use of gonadotropins did not increase the pregnancy rate. Out-of-the season, the eCG group had a higher concentration of P4, and the GnRH group was not efficient in inducing estrus.