Serum biochemical profiles of dairy cows with mid-lactation milk fever

The aim of the present study was to compare blood biochemistry of lactating dairy cows receiving veterinary treatment for mid-lactation milk fever with the profile of healthy controls. Mid-lactation milk fever in dairy cows is defined as hypocalcemia not accompanied by detectable clinical manifestations of other diseases. We investigated serum samples from 20 nonambulatory cows diagnosed with mid-lactation milk fever and found that calcium, magnesium, and inorganic phosphate perturbations mimics the profile expected in periparturient hypocalcemic paresis and we conclude that mid-lactation milk fever is a disorder related to the calcium metabolism in lactating dairy cows. We observed elevated serum concentrations and activities of serum amyloid A, interleukin-6, serum non-esterified fatty acids, and aspartate aminotransferase in cows suffering from mid-lactation milk fever, however, none of these variables correlated with the magnitude of the perturbation of the calcium status of the nonambulatory cows. The cause of mid-lactation milk fever is unknown.