Efficacy of Ovulation Synchronization Protocols for Dairy Heifers and Evaluation of an Early Non-Pregnancy Diagnosis Test in Dairy Heifers
Dairy operations require continuous replacement of lactating cows. The productive life, milk yield, reproductive performance, and health of primiparous Holstein cows is closely related to age at first calving (AFC) and weight immediately after calving, being the recommended AFC in Holsteins < 24 months with body weight (BW) above 560 kg after calving. However, data regarding age and BW of primiparous Holstein cows after calving demonstrated that only 2.7% of dairy farms in the United States achieve the recommended target. Therefore, implementation of reproductive management that maximizes the number of pregnant heifers at a certain age and weight has the potential to improve profitability of dairy farms. Pregnancy diagnosis is performed as early as 33 days after AI by palpation of uterine content in commercial US dairy herds and early pregnancy
diagnosis can be performed in dairy cows at around 26 days after AI with the use of ultrasound, allowing for early re-insemination of non-pregnant. The development of a new blood test for diagnosis of non-pregnancy in cattle at 18 days post-AI has the potential to further reduce the interval between AIs and ultimately the calving to conception interval in lactating dairy cows. Development and evaluation of estrous cycle synchronization protocols that allow for fixed time artificial insemination in dairy heifers. Evaluate the sensitivity, specificity, negative predicted value, and positive predicted value of a new blood test for pregnancy diagnosis in the bovine female.