REPRODUCTIVE-PERFORMANCE OF DAIRY-COWS FOLLOWING TREATMENT WITH FENPROSTALENE, DINOPROST, OR CLOPROSTENOL BETWEEN 24 AND 31 DAYS POST-PARTUM - A FIELD TRIAL

Three hundred and one Holstein cows (n = 301), calving at a commercial free-stall dairy farm, were randomly assigned to 1 of 3 prostaglandin treatment groups or a placebo group. The placebos were packaged 3 way s to mimic the 3 commercial prostaglandin preparations. Group 1 receiv ed 1 mg fenprostalene and 1.6 mg oxytetracycline; Group 2 received the fenprostalene placebo (2 ml polyethylene glycol and 1.6 mg oxytetracy cline); while Group 3 was given 25 mg dinoprost. Group 4, the dinopros t placebo received 5 ml saline; Group 5 received 500 ug cloprostenol; and Group 6 the cloprostenol placebo received 2 ml saline. The treatme nts were administered between Days 24 and 31 post partum. Double blind techniques were used in administering treatments and in assessing the response to treatment. There were no significant differences among tr eatment groups with respect to incidence of retained fetal membranes, endometritis, pyometra, anestrus, number of services per pregnancy, ca lving-to-first estrus interval, services per conception, number of pro staglandin treatments other than those administered between Days 24 an d 31 post partum, the percentage culled for reproductive reasons and a ll factors combined. Cows receiving fenprostalene, dinoprost or clopro stenol had a decreased calving-to-conception interval compared with th at of the controls (P = 0.05). It is concluded that, in the herd studi ed, treatment with any of the 3 commercially available prostaglandin p roducts between Days 24 and 31 post partum was beneficial for reproduc tive performance.