Infertility in dairy cows: Ovarian dysfunction and hormonal imbalances

Normal pattern (Fig. 1) In normally cycling cows, resumption of ovarian activity generally occurs at around 7-10 days following calving. The resulting wave of follicular growth results in a dominant follicle that subsequently ovulates. This ovulation is followed by the formation of the progesterone-secreting corpus luteum (CL). Although the first cycle after this ovulation is often short, around 7-10 days, normal 18-24 day cycles then commence, which are only