CHANGE OF MILK-YIELD WITH CLINICAL-DISEASES FOR A HIGH PRODUCING DAIRY-HERD

Changes in milk production associated with occurrence of clinical diseases (dystocia, stillbirth, twin births, milk fever, retained placenta, displaced abomasum, limping due to foot lesions, metritis, ketosis, and mastitis) were investigated. Data were collected daily on 388 lactation. Stepwise lease squares regression was used to evaluate existence of associations between diseases and six yield measures that characterized milk production in the first 119 d postpartum. Logistic regression was used to investigate whether milk yield 1 to 5 d in milk might be of use to detect cows with early postpartum metritis (< 21 d after calving). Lower milk production to 5 d postpartum was associated with an increased risk of early postpartum metritis in the logistic regression model. Yield to 5 and to 21 d postpartum was lower in cases of still-birth, retained placenta, and early postpartum metritis. Yield from 22 to 49 d postpartum remained lower in cows diagnosed with early postpartum metritis. Milk yield losses occurred during diagnosis and treatment of displaced abomasum and mastitis. Ketosis was associated with yield losses prior to and at treatment. Ketosis to 21 d in milk was also associated with lower production after treatment. Limping diagnosed in the first 49 d postpartum coincided with higher yield to 5 d, to 21 d, and after 49 d postpartum.