The 1989 Annual KSU Dairy Day is known as Dairy Day, 1989Research in reproductive physiology and breeding management of dairy cattle at Kansas
State University has the following objectives: 1) to better understand those factors that influence the
reestablishment of ovarian function, estrous cycles, and fertility after calving and 2) to apply that
knowledge to areas of management in which pregnancy rates and calving intervals can be improved
in dairy herds. Our past efforts have included 1) pioneering research into the applications of
gonadotropin-releasing hormone (GnRH) at the time of insemination and early postpartum as a
prophylactic treatment for inducing estrous cyclicity; 2) application of treatments utilizing
prostaglandin F2α (PGF2α ) for breeding management of open cows, estrous induction for first services,
and postpartum therapy for cows with periparturient problems; 3) utilization of progesterone-releasing
intravaginal devices (PRIDs) to induce estrus and enhance fertility; 4) studies aimed at understanding
estrous behavior, including the influence of the thyroid gland; 5) efforts to understand the influence
of progestogens on the function of the corpus luteum; and 6) estrous synchronization of heifers and
cows utilizing PGF2α