Horton, Lucas M.2018-11-022018-11-022018-12-01http://hdl.handle.net/2097/39237Three studies evaluated effects of high-amylase corn (Enogen® Feed Corn, EFC) on ruminal digestive characteristics using different processing methods; a 4th study evaluated performance of finishing cattle fed steam-flaked EFC. In study 1, mill-run corn (CON) and EFC were ground through 9-, 6-, or 4 -mm screens, blended to contain 0, 33.3, 66.7, or 100% EFC, and heated to 50, 75, or 100⁰C (plus a non-heated control). No 2- or 3-way interactions occurred (P > 0.05). Increasing EFC in blends linearly improved in situ dry matter disappearance (ISDMD; P < 0.01) and in vitro gas production (IVGP; P = 0.02). Study 2 used blends of EFC and CON containing 0, 25, 50, 75, or 100% EFC, which were reconstituted to 27, 30, or 33% moisture, and ensiled. High-amylase corn did not affect ISDMD (P = 0.19) but IVGP increased linearly (P < 0.01) in response to greater amounts of EFC. Acetate:propionate ratio and total volatile fatty acid (VFA) production by in vitro fermentation improved linearly by increasing EFC (P < 0.02). Study 3 used the same blends of EFC and CON as study 2. Grains were tempered with 0, 3, or 6% moisture, steam conditioned 15, 30, or 45 min, and flaked. No 2- or 3-way interactions occurred. Starch availability, ISDMD, IVGP, and in vitro production of acetate, propionate, and total VFA increased linearly (P < 0.01) with greater flaked EFC in blends. Study 4 fed finishing diets consisting of steam-flaked CON, or EFC, for 136 d to 700 crossbred beef heifers (394 ± 8.5 kg initial BW). Compared to CON, cattle fed EFC had similar DMI (P = 0.78) but had greater ADG (P < 0.01) and a 5% improvement in feed efficiency (P < 0.01). Carcass weight was 6 kg greater for EFC cattle (P < 0.01), which also had 8% fewer liver abscesses (P = 0.03) than CON. Marbling score was greater in CON cattle (P = 0.04) than EFC; no differences in USDA Quality Grade (P = 0.33), Yield Grade (P = 0.13), LM area (P = 0.89), or 12th-rib fat thickness (P = 0.21) were evident. Improvements in digestion associated with EFC are likely confined to that component of grain mixtures due to a lack of quadratic effects. Improvements in feed efficiency, carcass weight, and potential liver abscess mitigation may be of advantageous use for producers.en-US© the author. This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).http://rightsstatements.org/vocab/InC/1.0/amylasefeedlothigh-amylase cornsteam-flakingThesis