Carcass physical composition of Holstein calves fed diets with different levels of concentrate

The objective of this study was to evaluate the effect of different dietary levels of concentrate on the carcass physical composition. Thirty two pure Holstein black and white type bull calves, into two slaughter groups (group 1: 16 animals slaughtered with 190 +/- 10 kg PV and group 2: 16 animals slaughtered with 300 +/- 10 kg) with average of 75 days of age and initial 75 kg LW were allotted to a completely randomized design, with four treatments and four replicates for both groups. The animals were full fed diets containing 45.0, 60.0, 75.0, and 90.0% concentrate in the diet (% DM), using coast-cross (Cynodon dactylon) grass hay, corn meal and soybean meal, which constituted diets with approximately 16% CP. At each 28 days period, the animals from each group were weighed and slaughtered at preestablished weights for the groups 1 and 2. The increase of the concentrate levels in the diets only affected proportion of bone in the carcass of the animals of group 1, were not affected, however that of muscle decreased and that of fat, adipose tissue:bone ratio and adipose tissue:muscle ratio linearly increased with the concentrate levels in the diets. The increase of dietary concentrate levels only influenced the muscle:bone ratio in the carcass of the animals of the group 2.