Caracterização morfológica da divergência folicular em vacas da raça Tabapuã (Bos taurus indicus) tratadas com somatrotofina bovina

Abstract

The aim of the study was to evaluate the effect of bovine somatotropin in follicular deviation of sixteen Tabapuã cows. The animals received an ear implant of progesterone and 1 mg of estradiol benzoate, IM (day 0). On day 5, the females were divided into 2 groups: GI (control, n=8) and GII (treated with 500 mg bST, n=8). On day 10, the implants were removed and injected 500 µg of PGF2α in all cows. Only cows with follicles bigger 9 mm received 300 µg of GnRH. Ultrasound examinations were performed each 12 hours. There was no statistical difference between the follicular deviation in GI (2.4 days) and GII (2,1 days). At the divergence moment, FD and FS of GI were 6.28±0.42 and 6.26±0.41 mm, respectively, and FD and FS of GII were 6.08±0.72 and 6.12±0.39 mm. The mean maximum diameter of FD after ovulation was at 110.0±8.43 hours in GI and 115.2±8.98 hours in GII. FS reached the maximum diameter at 55.0±20.0 hours in GI and 76.8±10.46 hours in GII. The mean maximum diameter reached by FD and FS in GI was 8.85±0.41 and 6.5±0.42 mm, respectively, and GII 9.83±0.63 and 6.87±0.35 mm. There was no significant difference (p> 0.05) in diameter of FD and FS, neither in growth rates (mm/12 hours) of the FD before and after the deviation, neither in the moment of follicle deviation