INFLUENCE OF GRAIN TYPE AND OIL CONCENTRATION OF DRIED CORN DISTILLERS GRAIN WITH SOLUBLES ON RUMINAL FERMENTATION AND IN VITRO GAS PRODUCTION IN CATTLE FED HIGH-CONCENTRATE DIETS

To determine the effects of grain type (rolled-corn vs rolled-barley) and dried corn distillers grains with solubles (DDGS) oil concentration (low = 4.5 % vs moderate = 7.9 %) on ruminal pH, ammonia (NH3) and volatile fatty acid (VFA) concentrations, in vitro enteric methane (CH4) and carbon dioxide (CO2) production, and digestive enzyme activity, eight ruminally cannulated Holstein steers (715 ± 61.4 kg) were used in a 4 × 8 Latin rectangle with a 2 × 2 factorial arrangement of treatments. Diets were offered for ad libitum intake. Experimental periods were 24 d with 7 d of diet adaptation, 7 d of sample collection, and a 10-d transition between periods. No differences were observed for ruminal NH3, total VFA concentration, pH, or in vitro concentration of CH4 or CO2 after 24 hr of incubation among treatments. The lag time for in vitro gas production and degradation was greater (P = 0.03) from steers fed diets containing rolled-corn than rolled-barley. There were grain type × DDGS interactions (P ≤ 0.02) observed for α-amylase and trypsin activity (U/L ruminal fluid). Maltase activity (U/L ruminal fluid) was greater (P ≤ 0.01) in steers fed diets containing rolled-corn than rolled-barley and in steers fed diets containing low- compared to moderate-oil DDGS. These results indicate that, although ruminal enzyme activity was influenced, feeding different grain types (rolled-corn vs. rolled-barley) or DDGS with differing oil concentration (moderate vs. low) did not negatively influence ruminal fermentation or in vitro CH4 production.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author