The effect of protein source on the growth and carcass characteristics of veal calves

Abstract

One hundred and sixteen Holstein bull calves averaging 73.8 kg were assigned to a randomized block design with two treatments and 10 pens per treatment to determine the effect of protein source on growth and carcass grade. Treatments consisted of a mixture of whole shelled corn and protein supplement containing either soybean meal (SBM) or fishmeal (FM). Diets were fed ad libitum until the animals reached 225 kg. Calves were then shipped to a commercial abattoir to determine carcass yield and grade. Daily gain (1.37 kg) and days to reach market weight (112.7 d) were similar for animals fed SBM and FM. Calves fed FM were more efficient in converting dry matter to weight gain (2.64) than calves fed SBM (2.77) which was the result of the lower dry matter intake observed for FM (3.66 kg d−1) compared to SBM (3.80 kg d−1) calves. Carcass grade was similar for both treatments with most of the carcasses grading A. Muscle color score was not different between SBM and FM. However, warm carcass weight and dressing percentage were higher for FM (135.1 kg and 60.0%) than for SBM (133.0 kg and 59.0%). Nitrogen degradability of FM (57.1%) was significantly lower (P < 0.05) than that of SBM (61.8%). After a 9-h incubation in the rumen methionine disappearance was higher for FM (50.0%) compared to SBM (33.3%). Substituting partially soybean meal for fishmeal in diets of veal calves slightly improves feed efficiency and dressing percentage due probably to a lower intake on the FM supplemented diet. Key words: Calves, carcasses, protein, degradability