Abstract
Physiological and pathological variations of plasma phospholipids and total cholesterol were assessed in cattle under various physiological conditions and with liver dysfunction. The plasma concentration of phospholipids tended to increase with an increase in crude lipid content/cattle of feed, but the plasma phospholipids/total cholesterol ratio (PL/T-cho ratio) was almost stable. The plasma phospholipid was steadily reduced in concentration by and soon after parturition. The plasma phosphatidylcholine/sphingomyelin ratio (PC/SM ratio) was decreased around parturition but was increased again with an increase in plasma phospholipid concentration after parturition. The PL/T-cho ratio showed a peak around parturition, with a subsequent decrease following. The change in the PL/T-cho ratio showed a similar pattern to that in serum total bile acid concentration. A follow-up observation in diseased cattle (No.1) revealed a reduction in the plasma PL/T-cho ratio at the time of the onset of liver disease and the following increase lasted until remission of the clinical symptom. In idiopathic cardiomyopathy, the plasma PL/Tcho ratio was reduced at 6-3 weeks before the onset. The PL/T-cho ratio tended to increase in milking cattle having liver damage, but the plasma PC/SM ratio did not show any significant variation compared with the control cattle. Since the plasma PC/SM ratio showed large physiological variations, the usage for clinical diagnosis is not recommended. On the other hand, PL/T-cho in plasma may be a useful indicator for prognosis, because it varied with the pathological states.
