Histrelin acetate-induced ovulation in Brazilian Northeastern jennies (Equus asinus) with different follicle diameters

Abstract The aim of the present study was to evaluate the efficacy of a GnRH analog for induction of ovulation in Brazilian Northeastern jennies ( Equus asinus ) with different follicle diameters. Four consecutive estrus of 10 jennies were used in a crossover study; C (Control, n = 10) jennies were evaluated by transrectal palpation and ultrasonography until a spontaneous ovulation and the intervals between the predetermined follicular size (25–28 mm [C1], 29–32 mm [C2] and 33–36 mm [C3] follicle) and ovulation were registered. In treated cycle, jennies had the ovulation induced by 250 μg of Histrelin acetate (Strelin ® , Botupharma, Botucatu, Brazil) when respective follicle diameters 25–28 mm (T1), 29–32 mm (T2) and 33–36 mm (T3) were diagnosed. Ovulation was monitored by transrectal palpation and ultrasonography. Different follicle diameters significantly affected (P   0.05) from each other. Edema scoring and ovulation were not associated events (r = 0.0219). In conclusion, jennies with 29–32 mm follicles satisfactory responded to ovulation induction with Histrelin acetate, which allowed the shortening of interovulatory interval in all groups evaluated.