Influence of the breed of fetus on physiological, endocrine and production responses of ayrshire dams during the periparturient period

Abstract

The superovulatory response in buffaloes was studied when either early cycle priming with gonadotropins or GnRH was used in a superovulatory regimen with Folltropin. Twenty-four buffaloes were randomized into three groups and superovulated with FSH (Folltropin; total dose 25 mg) and Prostaglandin F2 alpha (PGF). Animals in Group A were primed with two doses of FSH (Folltropin; 2.5 mg each) on Days 3 and 4 of the estrous cycle prior to superovulation; those in Group B were given an injection of GnRH 48 h after first injection of (PGF); and those in Group C served as controls. Five or 6 days after estrus the number of corpora lutea (CL) and unovulated follicles (> 10 mm) were recorded. Daily blood sampling allowed estradiol and progesterone determination. The overall mean (± SEM) number of CL palpated on the ovaries of each animal was 2.69 ± 0.38 and this did not differ significantly among treatment groups. Progesterone levels on the day of initial FSH injections and on the day of palpation (per rectum) were positively correlated with ovulation rate. It was concluded that priming of donor buffaloes prior to superovulation or administration of GnRH on the day of estrus had no effect on the onset or duration of estrus, ovulation rate or steroid profile.