Body composition and bone mineralization measurement in calves of different genetic origin by using dual-energy X-ray absorptiometry

The purpose of this study was to investigate the differences in bone mineralization [bone mineral density (BMD, g/cm(2)) C, and bone mineral content (BMC, %)] and body composition of F1 and F2 crossbred calves and their purebred controls from the dairy breeds German Holsteins (GH) and German Fleckvieh (FV). In total, 62 male and 64 female calves were analyzed under light sedation with dual-energy X-ray absorptiometry (DXA). The study started when the calves were 4 days old and continued until they were 60 days old. GH calves had a significantly lower BMD than all other lines - with the highest BMD and BMC in the FVmale x Flfemale line. Since the average BMD of the F1 calves was higher than the average BMD of their parents, a small heterosis effect for this trait seems likely. The absolute differences in soft tissue composition were small with a slightly higher average fat content for F1 calves compared with the parent breeds.