Impact of dystocia in primiparous cows on lactational performance and survival

The objective of this study was to determine performance losses in primipar ous cows caused by dystocia. 1384 primiparous cows of a commercial dairy we re included in the analysis. They were classified according to the course o f their calving as normal delivery (n = 539), mild (n = 447) and severy dys tocia (n = 398). Risk of culling and risk of at least one case of clinical mastitis during the first lactation were compared using survival analysis. Milk production and somatic cell counts were corrected for month of calving and compared using one way ANOVA. Severe dystocia increased the risk of cu lling and of acquiring at least one case of clinical mastitis during the fi rst lactation significantly. Milk production was reduced during the first t wo months of lactation. However, somatic cell counts were not influenced si gnificantly by severe dystocia. The percentage of cows bred and conception rate were lower in primiparous cows with dystocia. Days to first service an d days open were longer. The economic losses associated with mild and sever e dystocia added up to DM 53.85 and DM 220.49 per cow, respectively. In the se figures veterinary treatment costs and discarded milk after treatment we re not included.