Controle da ovulação em novilhas bubalinas em clima tropical fora da estação reprodutiva

Abstract

The buffalo species present reproductive seasonality, such trace results in heterogeneity in milk supply to the consuming market during the year, with radical variations in the price of milk-related products. Induction of ovulation in heifers during adverse reproduction season through hormontherapy followed by TAI, is an alternative capable of making milk production stable. It was aimed to assess follicular dynamics and induction of ovulation synchronized in buffalo heifers from Murrah breed making use of different external inductors of ovulation during unfavorable breeding season. It was used protocols of synchronization of ovulation based on the use of GnRH, progesterone, prostaglandin and eCG, in 48 buffalo heifers of the Murrah breed divided in G1 (n=14), G2 (n=17) and G3 (n=17). For evaluation of follicular dynamics, eight heifers from each group were randomly selected. As an inductor of ovulation G1 received only 0,25 mg of Gonadorelin Acetate; G2 received 0,25 mg of Gonadorelin Acetate and 0,75 mg of d-Cloprostenol, and G3, only 0,150 mg of d-Cloprostenol. Data from follicular dynamics were analyzed by ANOVA. No statistic difference (P > 0,05) was observed among groups referring to the growth rate of the dominant follicle, diameter of the pre-ovulation follicle, diameter of the corpus luteum, interval between the removal of the progesterone implant and ovulation and the rate of ovulation. The serum concentration of P4 at D18 was higher for G2. The induction of ovulation during adverse reproduction season was possible, and the d-Cloprostenol capacity for inducing ovulation in buffalo heifers was evidenced, being it associated with GNRH or not, whereas in association there was not the maximization of the ovulation rate.