[Behavior of back fat thickness, the activity of NADP-dependent dehydrogenases from adipose tissue and adipose tissue constituents fat and protein and their evidence for energy metabolism in dairy cows].

: Studies were conducted into 60 Friesian dairy cattle in the GDR for determination of dorsal fat thickness (DFT), activities of glucose-6-phosphate dehydrogenase (GPDH) and isocitrate dehydrogenase (ICDH) in adipose tissue, concentrations of fat and protein in adipose tissue, 2 weeks ante partum as well as 0, 2, 4, 6, 8, 12, 16, 20, 28, 36 weeks post partum, and liver fat levels, 2 and 4 weeks post partum. DFT, ICDH, GPDH, ICDH-GPDH ratio, fat level, fat-protein quotient, changes in DFT, GPDH, and fat-protein quotient exhibited significant relations with the weeks of lactation. The above 60 experimental cows were subdivided by 6 groups of half-siblings consisting of 10 animals each. Significant differences were found to exist between these groups of half-siblings with regard to DFT, GPDH, ICDH-GPDH ratio, and fat-protein quotient. Within each of the half-sibling groups, significant differences were found to exist between individuals for DFT, ICDH, GPDH, ICDH-GPDH ratio, and fat-protein quotient. The above parameters can be used to describe the energy metabolism of dairy cow via quantitative and temporal curves of fat mobilisation and fat deposition. In the context of both animal health and breeding, more attention should be given to determination of mobilisation and deposition of fat as well as to the post partum energy deficit.