Effect of oestradiol benzoate given after prostaglandin at two stages of follicle wave development on oestrus synchronisation, the LH surge and ovulation in heifers

Abstract

Oestrus synchronization following prostaglandin-induced luteolysis is variable and dependent on follicle wave status in cattle. Oestradiol benzoate (ODB) has been used following prostaglandin to reduce the interval to oestrus and ovulation, but the effect of follicle wave status at the time of ODB administration is not clear. The aim of this study was to characterize the endocrine and follicular responses following ODB after luteolysis at different stages of the follicle wave. Prostaglandin was administered at either emergence or dominance of the second follicle wave. Twenty-four hours later anìmals received either 0.5 mg ODB in oil or a control oil injection. Follicular development was moni..