[Effects of glucocorticoids on parameters of lipid metabolism, hepatic metabolism, haematological parameters and milk yield in high-yielding cows in early lactation].

Effects of glucocorticoids on lipid metabolism, hepatic metabolism, haematological parameters and milk yield in high-yielding cows in the early stages of lactation. The assumption is widespread that glucocorticoids promote lipolysis and fatty liver in ruminants. But there are contrary experimental results. Therefore we investigated the effects of dexamethasone (in the form of Voren suspension) in cows with very high milk yields (herd average 10.000 kg/year) between 7 and 15 days post partum, when high levels of lipolysis occur. Nine cows were given Voren 7 and 11 days post partum at doses of 0.02 mg/kg body weight. Glucose and insulin concentrations rose whilst FFA concentrations fell. Hepatic lipid levels were unchanged compared to a control group (n=8). There were also no changes in the various liver function parameters tested (beta-hydroxybutyrate, bilirubin, cholesterol, albumin, aspartat-amino-transferase, glutamat-dehydrogenase), which suggests that liver damage did not occur. Each of the two doses of Voren resulted in typical glucocorticoid-related changes in the differential leukocyte count. There was only a very slight reduction in daily milk yield. This studies show that, in ruminants, glucocorticoids have an indirect antilipolytic effect in vivo and do not aggravate or accelerate fatty degeneration of the liver.