use of corn and barley in diets for veal calves: effects on performance, diet digestibility and carcass quality

Forty Holstein bull calves (73.6 +/- 6.3 kg) were used in a randomized complete block design to determine if varying the corn-to-barley ratio in the diet affects growth, diet digestibility and carcass quality of grain-fed veal calves. Five diets consisting of corn:barley ratios of 100:0,75:25, 50:50, 25:75, 0:100 were offered and with a protein supplement (43.6% CP). Grain-to-protein supplement ratios were 2:1, 3.5:1 and 5:1 for the starting, growing finishing phases, resulting in diets of 23.5, 20.3, and 18.7% CP, respectively. Incidence of diarrhea increased with an increase in dietary barley (P < 0.05). Apparent digestibility of diets decreased as the proportion of barley increased (P < 0.01). Throughout the experiment, DMI was the highest for diets containing 75% barley and the lowest for those containing 100% corn (P < 0.01). Average daily gains behaved in a quadratic manner during the starting phase only (P < 0.01). This effect became linear during the growing and finishing phases, with ADG decreasing as dietary barley increased (P < 0.01). Average feed to gain ratio increased linearly with dietary barley content (P < 0.01). Hot carcass weights and yields decreased linearly with increasing proportions of barley (P < 0.01. Carcass color was not affected by treatments. Carcass classification tended to decrease as dietary barley increased. The results indicate that compared with barley, the use of corn improves performance and diet digestibility of grain-fed veal.