Risk factors for prebreeding pyometra on four Colorado dairy farms

Risk factors associated with pyometra were studied in 4 confinement managed dry-lot dairies in Colorado. The incidence of pyometra for the 3-year study was 7.0%. The first risk factor to enter the step-wise logistic regression model was “lactation number”. Cows in their first lactation were at lesser risk of developing pyometra (P<0.001) than cows in all other lactations. The second and final variable to enter the logistic regression model was “dairy farm”. Cows on 1 of the dairy farms were at lesser risk of pyometra than the other herds, (P<0.005), after adjusting for the lactation number of the cows. There was no statistical association for year or season with the incidence of pyometra; however, the probability of three consecutive spring seasons having the greatest frequency of pyometra was 0.0045.