Effects of Dystocia on the Postpartum Complications, Milk Production and Reproductive Performance in Dairy Cows

Abstract

This field study investigated the effects of dystocia on the postpartum complications, milk production, and reproductive performance in Holstein dairy cows. Calving difficulty was scored on a rank scale of 1 to 5. Cows with a calving score of three or higher were judged to have dystocia. The cows (n = 565) were categorized based on the presence (n = 61) or absence (n = 504, control) of dystocia. The incidence of retained placenta (45.9% vs. 16.3%), metritis (39.3% vs. 17.1%), endometritis (47.5% vs. 16.3%) and pyometra (9.8% vs. 1.2%) were greater in cows from the dystocia group than those from the control group (p 0.05). The prevalence of culling was higher in cows from the dystocia group (26.2%) than in those from the control group (14.5%, p < 0.05). During the 5-month postpartum period, milk production was lower (p < 0.05) in cows from the dystocia group than in those from the control group. Furthermore, the hazard of insemination by 150 days in milk (DIM) was lower in cows from the dystocia group (hazard ratio [HR] = 0.64, p < 0.005) than in those from the control group. Logistic regression analysis revealed that the odds ratio for the probability of pregnancy after the first artificial insemination was 0.36 times (p < 0.05) higher in cows from the dystocia group than in those from the control group. The hazard of pregnancy by 360 DIM was lower in cows from the dystocia group (HR = 0.45, p = 0.0001) than in those from the control group. In conclusion, dystocia resulted in increased postpartum complications, and decreased milk production and reproductive performance in Holstein dairy cows, leading to increased culling.