The influence of inhibited prostaglandin biosynthesis on post-ovulatory oviductal ova transport in sows

Changes in prostaglandin and progesterone concentrations after ovulation se em to affect reproductive functions in the sow. The influence of lowered pr ostaglandin levels on ova transport velocity through the isthmus part of th e oviduct, and on progesterone concentrations, was studied during the secon d estrus after weaning in thirteen purebred Yorkshire multiparous sows. To determine the time of ovulation transrectal ultrasonographic examination wa s performed. In the second estrus, six sows were given intravenous injectio ns of flunixin meglumine (2.2 mg/kg body weight) every sixth hour from 4 to 8 h after time of ovulation until about 48 h after ovulation, at which tim e the sows were slaughtered. Blood samples were collected every second hour from about 12 h before ovulation until slaughter. Progesterone and prostag landin F-2 alpha (PGF(2 alpha)) metabolite levels were determined. Immediat ely after slaughter the isthmus part of the oviducts were cut into 3 equall y long segments and the number of ova in each segment, and in the upper par t of the uterine horns, was determined. Before start of treatment, PGF(2 al pha) metabolite levels were similar in the 2 groups (P=0.84). In the treatm ent group, PGF(2 alpha) values dropped to below the detection limit immedia tely after start of treatment, whereas in the control group the concentrati ons were quite stable throughout the sampling period (P=0.005). Ova recover y rate was 94 % in the treatment group and 95 % in the control group. At ti me of slaughter, in the treatment group ova had on average passed 2.1 segme nts whereas in the control group the ova had passed 2.5 segments (P=0.57). The progesterone levels increased continuously in both groups after ovulati on but there was no difference in the mean progesterone concentrations betw een the two groups before (P=0.96) or after (P=0.58) ovulation. It can be c oncluded that the transport of ova through the isthmus part of the oviduct is unaffected by an inhibition of prostaglandin synthesis immediately after ovulation. Furthermore, the post-ovulatory progesterone profile seems unaf fected by lowered PGF(2 alpha) levels. (C) 2000 by Elsevier Science Inc.