The relationship between packed cell volume and the course of disease in milk fever in dairy cows

Results from a field investigation involving 1086 cows with clinical milk fever, revealed a clear relationship between PCV at the time of first treatment and the subsequent course of the disease. Average PCV was progressively higher as the cows required one, two, or more than two treatments before recovery, and was highest in cows which subsequently failed to recover. PCV in healthy, periparturient cows was considerably lower than in cows with milk fever. PCV was negatively correlated with plasma Ca, and varied, moreover, with the time of first treatment in relation to calving, and also with the length of time the cow had been recumbent before being treated for the first time. PCV was also measured during the further course of the disease in cows which received more than one treatment (2nd to 6th treatments).