Effect of hormonal treatment on fertility in dairy cows with dystocia or retained fetal membranes at parturition.

Holstein cows (n = 445) that had experienced dystocia, retained fetal membrane, or both at parturition were used to determine the effects of GnRH, PGF2 alpha, or both on various reproductive measurements. Cows affected with these conditions were assigned randomly to each of four treatment groups. One group of cows was untreated, and three groups received GnRH once at 12 d postpartum, or GnRH at 12 plus PGF2 alpha at 26 d postpartum, or PGF2 alpha given at 12 and 26 d postpartum. Another group of 191 cows that calved normally were untreated. Conception rate after first AI was higher for cows treated with PGF2 alpha at 12 and 26 d postpartum. Cows affected with dystocia, retained fetal membranes, or both and treated early postparum with GnRH alone or followed 14 d later with PGF2 alpha did not have improved reproductive performance. Cows calving during the summer months of June through September experienced a reduction in the reproductive traits examined.