343 Feedlot performance and carcass characteristics of steers fed diets containing steam-flaked grain and corn silage from Enogen® Feed Corn

Abstract

Abstract Enogen Feed Corn (EFC; Syngenta Seeds, LLC) is genetically modified to express high concentrations of amylase. Our objective was to evaluate EFC as corn silage and as steam-flaked corn in diets fed to finishing cattle. A 2 x 2 factorial experiment was conducted with steers (n = 960; 388 ± 7.4 kg initial body weight), with factors consisting of silage source (Control or EFC) and grain source (Control or Enogen). Steers were blocked by initial body weight, assigned randomly within block to treatments, housed in 48 pens with 15 or 25 cattle per pen, and harvested after 138, 152, or 166 days on feed. Grains were steam flaked to densities of 360 or 386 g/L for Control and EFC, respectively. Diets (dry basis) consisted of 8% corn silage, 2% alfalfa hay, 74.5% flaked corn, 12% Sweet Bran, and supplement. Incidences of liver abscesses and carcass weights were recorded at harvest, and longissimus muscle area, 12th-rib subcutaneous fat thickness, marbling score, and USDA yield and quality grades were determined after 36 h of refrigeration. There were no interactions between grain source and silage source (P > 0.05) for feedlot performance. Cattle fed diets containing EFC silage consumed less dry matter (P < 0.01) and efficiency of gain was improved by approximately 5.3% (P < 0.01) compared to cattle fed Control silage. Average daily gain and dry matter intake were unaffected by grain source, but cattle fed EFC grain were less efficient (P = 0.02) compared to cattle fed control grain. Carcass weight was greater for cattle fed the combination of EFC silage and Control grain compared to other treatments (P < 0.05), but liver abscess incidence and other carcass measurements were unaffected by grain or silage source. Feeding Enogen Feed Corn as corn silage, but not as grain, improved feedlot performance of steers. Keywords: Enogen, corn silage, amylase