Effects of dry-rolled or steam-flaked corn finishing diets with or without twenty-five percent dried distillers grains on ruminal fermentation and apparent total tract digestion

• Published in: Journal of animal science 2009-11, Vol.87 (11), p.3630-3638
• Main Authors: May, M.L, Quinn, M.J, Reinhardt, C.D, Murray, L, Gibson, M.L, Karges, K.K, Drouillard, J.S
• Format: Article
• Language: English
• Subjects: ammonia; Animal Feed; Animal productions; Animals; Biological and medical sciences; Butyrates - analysis; cattle; Cattle - physiology; cattle feeding; corn; dietary fiber; digestibility; Digestion - physiology; distillers grains; dry matter intake; Edible Grain; ether extract; excretion; Feces; feed composition; feed processing; Fermentation - physiology; finishing; Food Handling; Fundamental and applied biological sciences. Psychology; Gastric Juice - chemistry; Isobutyrates; lactic acid; Lactic Acid - analysis; Male; neutral detergent fiber; organic matter; Pentanoic Acids - analysis; rumen fermentation; rumen fluids; starch; steers; Terrestrial animal productions; Valerates - analysis; Vertebrates; volatile fatty acids; Zea mays
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2008-0857

A metabolism study was conducted to evaluate ruminal fermentation and apparent total tract digestibilities of cattle finishing diets. Holstein steers (n = 16, 351 kg of BW) with ruminal cannulas were fed diets consisting of 0 or 25% dried corn distillers grains (DDG), using dry-rolled corn (DRC) or steam-flaked corn (SFC) as the principal energy source (2 x 2 factorial arrangement). The study was conducted in 2 periods, with 4 steers per treatment in each period. Periods consisted of a 12-d adaptation phase and a 3-d collection phase. Compared with DRC, feeding SFC decreased intakes of DM, OM, starch, NDF, and ether extract (P < 0.01), and steers fed SFC excreted less DM, OM, starch, NDF, and ether extract (P < 0.01). Compared with SFC, feeding DRC decreased ruminal concentrations of acetate, butyrate, isobutyrate, and isovalerate, and decreased the acetate-to-propionate ratio (P < 0.01). Compared with SFC, DRC decreased ruminal propionate, valerate, and lactate concentrations (P < 0.01). When compared with cattle fed SFC, ruminal pH of cattle fed DRC was less at 0 h and greater at 6 h postfeeding (P < 0.01). Ruminal ammonia concentrations were greater for DRC vs. SFC at h 0, 6, 10, 12, 14, 16, 18, 20, and 22 postfeeding (P < 0.05). Feeding DDG decreased consumption of starch and ether extract, but increased NDF intake (P < 0.01). Fecal excretion of ether extract was increased by adding DDG compared with diets without DDG (P < 0.05), resulting in less apparent total tract digestibility of ether extract for cattle fed DDG (P < 0.01). Ruminal lactate concentrations were increased with addition of DDG compared with diets without DDG (P = 0.01). Ruminal ammonia concentrations were less for steers fed 25 vs. 0% DDG at 2, 4, 6, 8, and 10 h postfeeding (P < 0.05). We conclude, based on these results, that ruminal fermentation and apparent total tract digestibility of DDG are affected by grain processing.