PhD Oral Defence of Yasmin Schuermann, Animal Science
Longevity of dairy cows on our Canadian farms is dependent on reproductive success. The number one reason cows are culled is poor reproductive performance. This research aimed at better understanding the impact of metabolic changes occurring during the transition period (3 weeks pre-calving to 3 weeks post-calving) on ovarian health and evaluating pathways required for ovulation. We showed that the metabolic environment between lactating cows and nulliparous heifers leading up to the estimated time of breeding is drastically different, which strengthens the current knowledge that lactating cows are less fertile than nulliparous heifers. We also investigated the impact of body condition (BC) loss during the transition period leading up to estimated time of breeding on multiparous cows.