PATH-ANALYSIS FOR 7 POSTPARTUM DISORDERS OF HOLSTEIN COWS

Path analysis and multiple logistic regression with an extrabinomial variation error term (to account for herd) were used to model seven postpartum clinical disorders of dairy cows and factors related to the calf. Data were from 7761 lactation records from 34 commercial herds in the vicinity of Cornell University. Stillbirth increased the odds of developing metritis and retained placenta. The odds of developing dystocia and mastitis were lower when the sex of the calf was female. However, cows that twinned had increased odds of developing dystocia and retained placenta. Dystocia was related to an increase in the odds of retained placenta. Milk fever, dystocia, and ketosis each increased the odds of developing left-displaced abomasum. Postpartum periods with dystocia, retained placenta, or ketosis had increased odds of metritis. Two interaction terms involved parity: stillbirth for milk fever and retained placenta for ketosis. The extrabinomial variation error term contributed to the fit in all models.