Lack of an effect of prostaglandin injection at estrus onset on the time of ovulation and on reproductive performance in weaned sows

We evaluated the effects of a PGF2alpha analogue on time of ovulation and reproductive performance in multiparous Camborough sows (n=47). At onset of first post-weaning estrus, sows received either an intravulval injection of 3.75 mg of prostaglandin analogue (PGF) or, served as a non-injected control (CON). Beginning 24 h after the onset of estrus, transcutaneous ultrasonography was carried out every six h to determine time of ovulation. At 36, 54, and 72 h after the onset of estrus, blood samples were taken for progesterone analysis. Weaning-to-estrus (WEI), duration of estrus, ovulation rate and number of live embryos at d 28 of gestation were recorded. Treatment had no effect (P > 0.05) on any parameters measured. Duration of estrus classified as less or greater than the overall mean also had no effect (P > 0.05) on any of the parameters measured. Results indicate that treatment did not advance ovulation nor did it improve reproductive performance in sows. Overall, a negative correlation of WEI with the ovulation rate (P = 0.0005, r = -0.54) was established.