Effects of corn processing and dietary wet corn gluten feed inclusion on performance and digestion of newly received growing cattle.

Effects of corn processing and of dietary inclusion of wet corn gluten feed (WCGF) on growth performance and digestibility were analyzed in 2 experiments. Dietary treatments were arranged as a 2 × 2 factorial. Diets contained corn as either whole-shelled corn (WSC) or as dry-rolled corn (DRC), and they contained either 47% corn with no WCGF or 29% corn with 30% WCGF. In Exp. 1, 279 crossbred calves (230 kg) were allocated to treatments in a complete block design and were used to measure performance and digestion during a 60-d receiving period. Corn processing did not affect (P ≥ 0.31) growth performance. Inclusion of WCGF in the diet increased final BW and ADG (P = 0.03) but did not affect gain efficiency (P = 0.45). Digestibility of DM was increased (P < 0.01) by dietary inclusion of WCGF, and this response was greater in diets containing DRC than in those containing WSC (interaction P = 0.02). For Exp. 2, a digestibility trial used 5 ruminally cannulated Holstein heifers (248 ± 13 kg BW) in a 4 × 4 Latin square with the additional animal administered the same treatment sequence as another heifer. A tendency (P = 0.09) was observed for heifers fed DRC to have greater DMI than those fed WSC. Dietary WCGF inclusion increased (P ≤ 0.01) DMI. Similar to observations in Exp. 1, DM digestibility was improved by addition of 30% WCGF to diets containing DRC but not diets containing WSC (interaction P = 0.02). Ruminal pH was not affected by corn processing (P = 0.90), but it tended (P = 0.09) to be increased by dietary WCGF additions. Ruminal VFA concentrations were not different between WSC and DRC, but dietary inclusion of 30% WCGF decreased (P < 0.01) acetate concentrations and increased (P = 0.05) butyrate concentrations. Liquid passage rate from the rumen and ruminal liquid volume were not affected by corn processing or dietary WCGF inclusion (P ≥ 0.66). In summary, processing corn had no effect on steer performance, but including WCGF in the diet at 30% of DM increased gains of steers over the 60-d receiving period. Diet digestibility did not follow the same pattern observed for gains and efficiencies.