Replacement of corn grain by pearl millet grain in diets containing corn or elephant grass silage fed beef cattle

The objective of this experiment was to evaluate the effects of replacing corn grain by pearl millet grain in diets containing corn silage or elephant grass silage on feed intake, apparent digestibility of nutrients and ruminal parameters of beef cattle. Six cannulated Nellore steers were distributed in a 6 x 6 Latin square, in a 2 x 3 factorial scheme, with two sources of roughages (corn silage or elephant grass silage) and three levels of replacement of corn grain by pearl millet grain (0, 50 or 100%). Replacement of corn grain by pearl millet grain and the roughage sources did not affect nutrient intake. However, the use of elephant grass silage increased acid detergent fiber and decreased starch intake when compared to diets containing corn silage. There was no effect of replacement of corn grain by pearl millet grain on digestibilities of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber. However, there was an increase of digestibility of ether extract and the highest values were observed for diets containing 50 and 100% of pearl millet grain in relation to diets containg 100% corn grain, regardless to roughage source. Digestibility of starch was also increased by the replacement of corn grain by pearl millet grain. Roughage source also had an effect on neutral and acid detergent fiber digestibilities, which increased with the use of elephant grass silage. Replacement of corn grain by pearl millet grain in the diet decreases ruminal ammonia concentration without changing concentrations of ruminal acetate, propionate, total volatile fatty acids and ruminal pH. The use of elephant grass silage increases ruminal acetate concentration and acetate: propionate ratio.