Changes in
prostaglandin and
progesterone concentrations after ovulation seem to affect reproductive functions in the sow. The influence of lowered
prostaglandin levels on ova transport velocity through the isthmus part of the oviduct, and on
progesterone concentrations, was studied during the second estrus after weaning in thirteen purebred Yorkshire multiparous sows. To determine the time of ovulation transrectal ultrasonographic examination was performed. In the second estrus, six sows were given
intravenous injections 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 time the sows were slaughtered. Blood samples were collected every second hour from about 12 h before ovulation until slaughter.
Progesterone and
prostaglandin F2alpha (
PGF2alpha) metabolite levels were determined. Immediately after slaughter the isthmus part of the oviducts were cut into 3 equally long segments and the number of ova in each segment, and in the upper part of the uterine horns, was determined. Before start of treatment,
PGF2alpha metabolite levels were similar in the 2 groups (P=0.84). In the treatment group,
PGF2alpha values dropped to below the detection limit immediately after start of treatment, whereas in the control group the concentrations were quite stable throughout the sampling period (P=0.005). Ova recovery rate was 94% in the treatment group and 95 % in the control group. At time of slaughter, in the treatment group ova had on average passed 2.1 segments whereas in the control group the ova had passed 2.5 segments (P=0.57). The
progesterone levels increased continuously in both groups after ovulation but there was no difference in the mean
progesterone concentrations between the two groups before (P=0.96) or after (P=0.58) ovulation. It can be concluded 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 unaffected by lowered
PGF2alpha levels.