Apparent failure of prostaglandin F2a to improve the reproductive efficiency of postpartum dairy cows that had experienced dystocia and/or retained fetal membranes

Abstract

This study was designed to determine the effect of exogenously administered prostaglandin F2a (PGF2a) to dairy cows that had experienced either dystocia and/or retained fetal membranes on their fertility during the subsequent postpartum period. A total of 680 cows was used in this study. Three groups were formed on the initial day (Day 0) of examination: Group 1 (n = 115), Group 2 (n = 114) and Group 3 (n = 451). Groups 1 and 2 were comprised of cows which had experienced dystocia and/or retained fetal membranes. Cows in Group 3 had calved normally and did not experience any adverse effects of the reproductive organs. Cows in Group 1 were treated with PGF2a (25 mg i.m.) on Day 0, while cows in Group 2 served as the abnormal, untreated controls. On Day 14, cows in Groups 1 and 2 were examined for normalcy. The reproductive parameters evaluated for all Groups were the percentage of cows becoming pregnant during 90, 120 and 180 d after calving; the mean number of services per pregnancy; and the mean days open. Data were analyzed using general linear models procedure for analysis of variance (P<0.05). The percentage of cows pregnant at 90, 120 and 180 d in Group 3 was significantly higher than that for cows in both Groups 1 and 2. The mean number of services per pregnancy and the mean number of days open for cows in Groups 1 and 2 were significantly greater than values for cows in Group 3. There was no significant difference between the values for these parameters for cows in Groups 1 and 2. The results of this study suggest that prostaglandin treatment of postpartum cows which had experienced dystocia and/or retained fetal membranes had no beneficial effect on fertility during the succeeding postpartum period.