Animal Science, Department of


Date of this Version



2016 Nebraska Beef Cattle Reports


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Within the physiology herd, a group of cows that have excess androgen (androstenedione, A4) in the dominant follicle and a 17% reduction in calving rate have being identified. Thus, our objective was to determine follicular dynamics (follicle growth) and progesterone (P4) concentrations in High A4 cows to determine if they were anovulatory. High A4 cows had more persistent dominant follicles and either did not display estrus and ovulated at an inappropriate time or did not ovulate compared with Low A4 cows (Controls). Furthermore, P4 concentrations had reduced peak values and were maintained longer in High vs Low A4 cows which may contribute to their failure to ovulate.

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