INTERRELATIONSHIPS AMONG HEALTH-PROBLEMS AND MILK-PRODUCTION FROM CONSECUTIVE LACTATIONS IN SELECTED ONTARIO HOLSTEIN COWS

Clinical health problems and milk production data from Holstein cows from 34 commercial south-western Ontario dairy herds, for which two subsequent lactations were available, were investigated. Associations of health problems and milk production from a previous lactation with the occurrence of health problems in the following lactation were investigated using a stepwise logistic regression procedure. Milk fever, teat injuries and mastitis were the only problems that were associated with previous milk production. Retained placenta, mastitis and ovarian cysts in a lactation were predictors of the same events happening in the subsequent lactation. Long lactations without ovarian problems increased the risk of udder oedema occurring during the following lactation. Reproductive infectious problems showed less capacity to predict health problems in the subsequent lactation than did non-infectious problems. Lactations with low milk production and older animals increased the risk of difficulty at the following calving. © 1990.