Relationships between parameters of the glucose tolerance test by young sires and estimated their breeding values

A high milk performance connected to a sound health regarding metabolism an d a sufficient fertility in daily cows depends on a well balanced distribut ion of energy in body. The terms 'type of turnover' and 'type of deposition ' embody two extremes of food energy preferably for milk production or for body composition. Insulin plays an outstanding role based on its central po sition in energetic metabolism. The function of insulin may be recorded by means of the intravenous glucose tolerance test (GTT). The reaction of insu lin and glucose was investigated after infusion of 1 g Glucose/kg(0.75) bec ause of the probable genetic determination of the reactive ability. The coe fficients of heritability range from h(2) = 0.16+/-0.10 to h(2)= 0.28+/-0.1 6. investigating 28 sires the correlation coefficients amount to r = 0.5 fo r parameters of gluccose tolerance test and estimated breeding values which is closer than those between pedigree breeding value and glucose tolerance test. This is expecting additional information for young sires before the insert of the test.