Effect of Thermal Processing of Cereal Grain on the Performance of Crossbred Calves Fed Starters Containing Protein Sources of Varying Ruminal Degradability

In order to investigate the effect of incorporation of thermally processed cereal (maize) grain and differently degradable protein sources in the calf starter, twenty four newly born crossbred $(Bos\;taurus{\times}Bos\;indicus)$ calves were assigned at random to six diets in a $3{\times}2$ factorial design involving three protein sources viz. groundnut meal (GN), cottonseed meal (CS) and meat and bone meal (MB), each along with two differently processed grain, namely ground raw (R) and pressure cooked (P) maize. The corresponding calf starters with green oats (Avena sativa) were given free-choice from 14 d onwards till the end of the 90 d experimental feeding. A restricted milk diet was fed till the age of weaning at 60 d. Total DM intake was not affected by cereal or protein sources. However, daily intake of DM (59.23 vs 66.45 g) and CP (12.38 vs 14.10 g) per kg $W^{0.75}$ was reduced (p<0.05) due to cereal processing. Better (p<0.05) feed and protein efficiencies after weaning and during entire period in calves fed processed maize resulted in a trend of higher $(p{\leq}092)$ growth rate especially when GN was the source of protein. In comparison among protein sources, calves fed MB diets tended to grow faster $(p{\leq}098)$ concurrent with a higher CP intake before weaning. It is thus evident that thermal processing of maize in the calf starter seems to improve calf performance. Moreover, results indicated that feeding of protein and starch sources of matching ruminal degradability may prove beneficial for early growth of crossbred calves.