Effects of high-amylase corn on performance and carcass quality of finishing beef heifers

• Published in: Journal of animal science 2020-10, Vol.98 (10), p.1-10
• Main Authors: Horton, Lucas M, Van Bibber-Krueger, Cadra L, Müller, Hans C, Drouillard, James S
• Format: Article
• Language: English
• Subjects: Abscesses; acetates; Acetic acid; Agricultural production; alpha-amylase; Amylases; Amylases - administration & dosage; Amylases - chemistry; Amylases - metabolism; Amylases - pharmacology; Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; Availability; average daily gain; Beef; Beef cattle; Body Composition; Body weight; butyrates; carcass quality; carcass weight; Carcasses; Cattle; Cattle - physiology; Cereal crops; Conditioning; Corn; Diet - veterinary; Digestion; Digestion - physiology; Dry matter; Ethanol; ethanol fuels; ethanol production; fat thickness; Fatty acids; Fatty Acids, Volatile - pharmacology; feed conversion; Feed efficiency; Female; Gas production; Genetic modification; Grain; Liver; liver abscess; longissimus muscle; marbling; Meat quality; Microorganisms; Moisture; Muscles; Oil and gas production; Plant protection; Propionic acid; Quality; Ruminant Nutrition; seeds; Starch; Starch - pharmacology; Steam; USDA; Vegetables; volatile fatty acids; Zea mays - enzymology; α-Amylase
• ISSN: 0021-8812; 1525-3163; 1525-3163
• DOI: 10.1093/jas/skaa302

Abstract Developed initially for use in fuel ethanol production, Enogen Feed Corn (EFC; Syngenta Crop Protection) is genetically modified to express high concentrations of α-amylase in the corn kernel. Experiments were conducted to evaluate processing characteristics of EFC, in vitro digestion, and effects on feedlot performance, carcass characteristics, and liver abscess incidence. Experiment 1 used a randomized complete block design (3 × 3 × 5 factorial) to evaluate starch availability, in situ dry matter disappearance (ISDMD), in vitro gas production (IVGP), and volatile fatty acid (VFA) profiles of in vitro cultures. Grains (EFC or mill-run control [CON]) were flaked to a density of 360 g/L, and mixtures with 0%, 25%, 50%, 75%, or 100% EFC were prepared. Grains were tempered with added moisture (0%, 3%, or 6%) prior to steam conditioning for 15, 30, or 45 min. No two- or three-way interactions were observed. Adding moisture improved starch availability (linear; P < 0.01), and tended to improve ISDMD (linear, P = 0.06). Steam conditioning for 30 min improved starch availability, IVGP, and production of acetate, propionate, butyrate, valerate, and total VFA (P < 0.01) compared with conditioning for 15 or 45 min. Starch availability, ISDMD, IVGP, acetate, propionate, valerate, and total VFA production increased with an increasing proportion of EFC (linear, P < 0.01). Experiment 2 used 700 beef heifers (394 ± 8.5 kg initial body weight [BW]) fed finishing diets with steam-flaked corn as CON or EFC for 136 d. Targeting similar starch availabilities, grains were processed to 360 g/L (CON) and 390 g/L for CON and EFC, respectively. Heifers were blocked by BW, stratified, and then randomly assigned to 28 dirt-surfaced pens (25 animals per pen). Dry matter intakes were similar between treatments (P = 0.78), but cattle fed EFC had greater average daily gain (P < 0.01), improving feed efficiency by 5% (P < 0.01). Hot carcass weight was 6 kg greater for EFC cattle (P 0.33). Cattle fed EFC had 23% fewer abscessed livers than CON (P = 0.03). High-amylase corn may be used to improve microbial digestion, mill-throughput, and cattle performance, and it may mitigate liver abscesses.