Effects of feeding corn containing an alpha-amylase gene on the performance and digestibility of growing cattle

Abstract

Two growth performance studies and two digestibility trials were conducted to evaluate the effects of feeding Enogen® Feed Corn silage and corn grain to growing cattle. In Exp. 1, there were a total of 4 diets offered for ad libitum intake. The 4 diets consisted of 2 varieties of corn (Enogen Feed Corn [EFC] vs. yellow #2 corn [CON]) with two different methods of corn processing (dry-rolled [DR] vs. whole-shelled [WS]) and were formulated to provide 1.13 Mcal NEg/kg dry matter (DM); corn grain was 28.6% of diet DM. Average daily gain (ADG) and ending body weight tended to be greater for calves fed EFC than for those fed CON (P < 0.10). Gain:feed (G:F) was better for calves fed EFC (P < 0.01), improving by 5.5% over calves fed CON. In Exp. 2, a digestibility trial was conducted using 7 cannulated Holstein steers fed the same diets from Exp. 1. Ruminal pH was not affected by corn variety (P > 0.82). Liquid passage rate was greater for CON-fed calves and associated with lower digestibility. Total tract DM and organic matter (OM) digestibilities were greater for EFC-fed calves (P < 0.04). In Exp. 3, there were 4 diets offered for ad libitum intake. Dietary factors were arranged as a 2 × 2 factorial and consisted of two hybrids of corn silage (EFC silage [EFC-S] vs. control silage [CON-S]) and two varieties of corn grain (EFC grain [EFC-G] vs. control [CON-G]; both were dry-rolled). Diets were formulated to provide 1.11 Mcal NEg/kg DM; corn grain was 38.5% of diet DM, and corn silage was 40% of diet DM. ADG was 6.0% greater (P < 0.01) and G:F was numerically (P < 0.14) 3.3% greater for calves fed EFC-S than for those fed CON-S, but substituting EFC-G for CON-G did not affect ADG or G:F. In Exp. 4, a digestibility trial was conducted using 8 cannulated beef steers fed the same diets as Exp. 3. Liquid passage rate (P > 0.20), ruminal pH (P > 0.23), and ruminal total volatile fatty acid concentrations (P > 0.27) were unaffected by treatment. Total tract digestibilities of DM and OM were numerically greater by 2.5 and 2.2%, respectively, for calves fed the EFC-S compared to those fed CON-S. Feeding a corn hybrid containing alpha-amylase enzyme improved G:F of growing calves. Feeding EFC can benefit the beef industry by allowing less processing of grain without sacrificing performance.