Plasma amino acid levels in the fat cow syndrome.

Assays of free amino acids in the plasma of 12 cows with the fat cow syndrome (FCS) and 17 healthy cows were carried out from parturition to 6 weeks of lactation. Plasma concentrations of phenylalanine, histidine, glutamic acid and lysine in the cows with FCS were significantly higher (P less than 0.01) than in the healthy cows. In contrast, the cows with FCS exhibited a (P less than 0.01) lower concentration of threonine, glutamine, asparagine and citrulline. It is suggested that the reported changes in the plasma amino acids of cows with FCS could be a reflection of the metabolic alteration in the control mechanism of gluconeogenesis. For the majority of plasma amino acids, no clear pattern emerged which could be associated with the time of sampling.