Effects of prostaglandin administration 10 days apart on reproductive parameters of cyclic dairy nulliparous goats

Abstract

This study reported the effects of prostaglandin (PGF 2α) administration 10 days apart on reproductive parameters of cyclic artificial inseminated (AI) nulliparous Alpine (n=9) and Saanen (n=9) goats. Animals received two doses of 22.5μg PGF 2α 10 days apart. After 1 st and 2 nd PGF 2α administrations, estrus was monitored at 12 h intervals, with a buck teaser. Plasma progesterone concentration (ng/mL) was determined from blood sampled on day 0 (1 st PGF 2α) and the following 5, 10 (2 nd PGF 2α), 15, 20, 25 and 30 days. After the onset of the second estrus, females were transrectally (5 MHz probe) scanned at 4 hour intervals until at least 8h after ovulation. Pregnancy was checked through transrectal ultrasound on days 20, 25, 30, 35 and 90 after insemination. All parameters studied did not differ between breeds (P>0.05). Estrous response and interval to estrus, respectively, after 1 st (78.9% and 50.6±17.2h) and 2 nd PGF 2α (88.9% and 50.0±14.8h) administration did not differ (P>0.05). Overall animals ovulating (100.0%), interval to ovulation after 2 nd PGF 2α (64.5±19.5h) and after estrous onset (18.0±9.1h), ovulation rate (1.3±0.5), diameter of ovulatory follicle (8.1±1.1mm) were recorded. Embryo loss occurred before day 30 of pregnancy. Estrus can be efficiently synchronized in nulliparous Alpine and Saanen goats with two doses of prostaglandin 10 days apart.