Parameters of glucose tolerance test traits in dairy cattle

Numerous studies in dairy cattle focused on measuring the content of hormones, metabolites and enzyme activities in blood. Response on glucose challenge in 620 dairy bulls within a defined period of 340 ... 450 days of age is targeted on within this paper. The time response course after glucose challenge was the basis for selecting corresponding response traits. Deviation from normal distribution was taken into account by means of comparing parameters of original data, after logarithmic transformation and breeding values obtained from both. The residual plots did not confirm the necessity of logarithmic transformation. After evaluating fixed effects trait-specifically, individual breeding values for glucose tolerance test traits were estimated. Heritability coefficients were promising for using these traits in cattle breeding. Trait specific heritability coefficients for GO was 0.22 and 0.26, for Ga 0.23 and 0.18, for GHL 0.31 and 0.39 from logarithmic and original trait observations, respectively.