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 r eproductive 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 contr ol (CON). Beginning 24 h after the onset of estrus, transcutaneous ultrason ography 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 proges terone analysis. Weaning-to-estrus (WEI), duration of estrus, ovulation rat e 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 cla ssified 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. (C) 2001 by Elsevier Science Inc.