Abstract
ABSTRACT. Arnone B., Negrão C.B., Brito L.F.C., Giometti I.C. & Castilho C. Follicular dynamics and plasma FSH concentrations during follicular deviation in the first post-ovulatory wave in tabapua (Bos indicus) cows treated with bovine somatotropin (bST). [Dinâmica folicular e concentração plasmática de FSH durante a primeira onda pós-ovulatória em vacas Tabapuã (Bos indicus) tratadas com somatotrofina bovina (bST)]. Revista Brasileira de Medicina Veterinária, 35(4):318-322, 2013. Programa de Pós-Graduação em Ciência Animal, Universidade do Oeste Paulista, Rodovia Raposo Tavares, Km 572, Presidente Prudente, SP 19067-175, Brasil. E-mail: calie@unoeste.br. The objective of the present study was to evaluate follicular dynamics and plasma FSH concentrations during the first post-ovulatory wave in Bos indicus cows treated with bovine somatrotopin (bST). Diameters of ovarian follicles and plasma FSH concentrations were determined every 12 h until 5 d after ovulation in 10 Tabapua cows, half of which had been treated with 500mg bST. Treatment did not affect follicular diameters, follicular dynamics, ovulation-to-follicular deviation interval, or FSH concentrations. Follicular deviation was characterized primarily by a decrease in the growth rate of the largest subordinate follicle and occurred 54 h after ovulation when plasma FSH concentrations were decreasing. Mean diameters of the dominant and largest subordinate follicles at the time of deviation were 6.31 and 6.24 mm, respectively. In conclusion, bST did not affect follicular dynamics and plasma FSH concentrations in B. indicus cows. Follicular deviation occurred during a period of decreasing FSH concentration and no diameter differences between the dominant and largest subordinate follicle were observed prior to deviation.