In vivo analysis of body composition and growth of calves of different genetic origin using dualenergy x-ray absorptiometry (DXA)

Abstract

In vivo body composition and growth of 214 calves (6-50 days old) of different genetic origin were analyzed using dual-energy x-ray absorptiometry (DXA). A whole body scan was performed. Looking at body composition there were differences among calf genotypes and parent genotypes. Purebred German-Holstein calves showed lower bone mineral density, bone mineral content, bone mineral percentage, fat tissue percentage and weight than the other genotypes. Opposite conditions existed for lean tissue percentage. Daily feed intake and tissue growth rates (lean tissue, fat tissue, bone mineral) were recorded from day 0 to day 50 of age. Further effects of birth type and lactation number of dam became obvious. Twins showed a significant higher daily gain than calves of single births. Heifer calves had highest daily gain between Scan 2 and Scan 3 in contrary to calves of cows of fourth or fifth lactation number. Within the study two scan modes were compared. A comparison between two scan modes 'normal' and 'pediatric large' showed a high correlation of selected values (r ≥ 0,90) except for lean tissue percentage (r = 0,62), fat tissue percentage (r = 0,70) and R-value (r = 0,69). In conclusion DXA is a very suitable method for examination of body composition and growth of calves.