Effect of early postpartum PGF2α treatment on reproductive performance in dairy cows with calving and puerperal traits.

The objective of this study was to evaluate the effects of early postpartum PGF two alpha treatment on reproductive performance in dairy cows with calving and puerperal traits. A total of 363 Holstein cows (128 primiparous and 235 multiparous) were selected based on the presence of at least one of calving and puerperal traits (dystocia, retained placenta, twin, abortion, and postpartum uterine infections) and were assigned to two groups (treatment and control) irrespective of presence or absence of luteal tissue. Cows in the treatment group were treated twice with 25 mg dinoprost 8 h apart on day 20 postpartum, and for the control group saline placebo was administered. As it was speculated that the timing of a second dose would mimic the release of endogenous PGF2α from the uterus, our hypothesis was that two doses of PGF2α 8 h apart may increase the duration of elevated plasma prostaglandin F2α metabolite concentration in these cows. Recorded reproductive variables included days to first estrus, days to first AI, first service conception rate, pregnancy by 150 days in milk, service per conception, open days, and the percentage of repeat breeder animals. The data were analyzed using SPSS (Version 15) (IBM North America, New York, NY, USA) and Minitab (Version 14) (Minitab, State College, PA, USA). Although early postpartum PGF2α treatment had no effect on days to first estrus (36.7 days vs. 34.9 days, P = 0.056) and days to first AI (70.5 days vs. 72.2 days, P = 0.537), it increased first service conception rate (47.1% vs. 27.6%, P < 0.001); and this was more remarkable in primiparous cows (64.7% vs. 25%, P < 0.001). PGF2α treatment reduced the mean service per conception (1.92 vs. 2.72, P < 0.001) and the mean open days (112 days vs. 144 days, P < 0.001), and increased pregnancy by 150 days in milk (DIM) (80% vs. 66%, P = 0.004). The prevalence of repeat breeder syndrome in cows with calving and puerperal traits was reduced by PGF2α treatment (10% vs. 29.8%, P < 0.001). In conclusion, treatment of cows with calving and puerperal traits twice with a luteolytic dose of PGF2α 8 h apart on Day 20 postpartum improved reproductive performance and reduced the prevalence of repeat breeder syndrome.