Effect of different prostaglandins on intrauterine pressure and uterine motility during dioestrus in experimental cows

Prostaglandins are widely used in the management of cows due to their luteo lytic activity. They also have a direct effect on the myometrium. The possi bility that dissimilar prostaglandin preparations differ in their contracti le effect was investigated. Intra uterine pressure was recorded during dioe strus of lactating dairy cows using an intraluminal pressure microtransduce r placed trans-cervically. After recording physiological uterine motility f or 30 min, prostaglandins (dinoprost, DL-cloprostenol, D-Cloprostenol), or a placebo, was administered intramuscularly, followed by a 2 h recording pe riod. Significant differences were observed in the area under the curves (P less than or equal to 0.05)and between the mean amplitude, whereas the num ber of spikes per 15 min and the baseline pressure during the last 3 min of each recording period did not differ significantly among treatments. The p eak values for the area under the curve and mean amplitude were observed be tween 15 and 30 min after the administration of DL-cloprostenol, while dino prost yielded the most stable plateau from this time until the end of the r ecording period. The results are in contrast to those of earlier studies co mparing the effects of prostaglandins after intravenous administration.