Thirty two Holstein black and white type bull calves averaging 75 days of age and initial 78 kg LW, divided into two slaughter groups (group 1: 16 animals slaughtered with 190 ± 10 kg LW and group 2: 16 animals slaughtered with 300 ± 10 kg LW) were allotted to a completely randomized design to evaluate the effects of crescent dietary levels of concentrate on the quantitative traits of the non integrate body parts of the animal carcass and the development of the gastrointestinal tract (GIT). The animals were full fed with diets contained 45.0, 60.0, 75.0 and 90.0% of concentrate on the DM basis, using coast-cross (Cynodon dactylon) grass hay and corn meal, and soybean meal, which constituted diets with approximately 16,0% 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 concentrate levels of the diet did not affect the weights, in absolute values and per 100 kg EBW, of reticulum-rumen (RR), small intestine (SI), large intestine (LI), hide, and internal fat and in the length of LI for both groups. For animals from the group 1, there was a quadratic effect on the omasum weight, while the abomasum weight, for both groups, linearly increased in function of concentrate levels in the diet. The length of SI, per 100 kg EBW, from animal of the group 2, decreased linearly, with the addition of concentrate in the diet. The weights of internal organs (MIO), in absolute values, from animals of the group 2 were not affected. However, animals from the group 1 were affected by the addition of concentrate in the diets. The weight of MIO, per 100kg EBW, for the animals from the group 1, were affected, but the mesenteric fat weight in absolute values and per 100 kg EBW, for animals from the group 2, linearly increased, with the crescent levels concentrate in diets.
Abomasum; holstein calves; concentrate; hide; intestine; mesenteric; omasum; internal organs; reticulum-rumen; blood
