In the current study, suckled Bos indicus cows that displayed estrus had a larger CL and greater serum P4 concentrations in the subsequent estrous cycles, as de-scribed for high-producing dairy cows[19]. Cows that did not display estrus due to a reduced diameter of the dominant follicle during the synchronized proestrus may also have suboptimal concentrations of estradiol [18,19], which might result in a suboptimal LH surge.