[The contributions of the hormones insulin, cortisol, somatotropin and total estrogen to the pathogenesis of sheep ketosis].

The concentrations of hormones, metabolites and electrolytes in plasma of 45 ewes have been examined repeatedly during gestation (day 80 to 149) and at the third day of lactation. Healthy single pregnant (n = 8) and twin pregnant ewes (n = 12) have been compared with ewes sick with subclinical (3-hydroxybutyrate > 1,0 mmol/l, n = 6) and clinical (3-hydroxybutyrate > 1,6 mmol/l, n = 19) pregnancy ketosis. The concentration of 3-hydroxybutyrate, glucose, calcium, sodium and growth hormone in the plasma of the healthy animals were higher post partum than ante partum, while the concentrations of inorganic phosphorus, cortisol and total oestrogen were lower post partum than during pregnancy. In the pregnant ewes the concentrations of 3-hydroxybutyrate, bilirubin, total oestrogen and growth hormone in the plasma increased, while the concentration of insulin decreased with raising number of fetuses. In comparison with the healthy twin pregnant ewes the animals with subclinical and clinical pregnancy ketosis showed increased values of bilirubin, glutamate-dehydrogenase, growth hormone, total oestrogen, cortisol and cortisol/insulin ratios as well as decreased values of glucose, insulin and potassium. Individual differences of the animals within their groups were observed for the examined hormones as well as for glucose, calcium, sodium and potassium (analysis of variance). Beside multiple pregnancy low insulin values and high cortisol/insulin ratios, which are obviously due to individual disposition, influence enhanced ketogenesis and disorder of glucostasis.