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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Cell Wall Biology and Utilization Research » Research » Publications at this Location » Publication #317843
Title: The effects on digestibility and ruminal measures of chemically treated corn stover as a partial replacement for grain in dairy diets

Author
item COOK, DAVID - University Of Wisconsin
item COMBS, DAVID - University Of Wisconsin
item DOANE, PERRY - Archer Daniels Midland
item CECAVA, MICHAEL - Archer Daniels Midland
item Hall, Mary Beth

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2016
Publication Date: 8/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62817
Citation: Cook, D.E., Combs, D.K., Doane, P.H., Cecava, M.J., Hall, M. 2016. The effects on digestibility and ruminal measures of chemically treated corn stover as a partial replacement for grain in dairy diets. Journal of Dairy Science. 99:6342-6351.

Interpretive Summary: Corn stover is an abundant agricultural residue that, due to its poor digestibility, has minimal utilization beyond a soil amendment and livestock bedding. Chemical treatments of grass straws have been shown to improve fiber digestibility. The purpose of our study was to evaluate the effects of partial replacement of corn grain with corn stover which was treated with calcium oxide to enhance fiber digestibility. As stover inclusion increased, total tract digestion of fiber did not change, the value of the lowest rumen pH increased, but feed intake and milk production decreased. The maintenance of fiber digestibility was not enough to counterbalance the removal of digestible nutrients from corn grain from negatively affecting lactation performance. Although other studies have suggested no negative performance effects of substituting calcium oxide-treated stover for forage, results of the present study recommend against use of treated stover as a replacement for corn grain for lactating dairy cows. This information will be useful to dairy producers and their nutritionists when considering what alternative feedstuffs can be used.

Technical Abstract: Alkaline treatment of gramineous crop residues can convert an abundant, minimally utilized, but poorly digestible straw into a moderately digestible feedstuff. The objective of this study was to evaluate the changes in digestibility and ruminal effects when calcium oxide-treated corn stover was substituted for corn grain in diets for lactating cows. Mature corn stover was treated with calcium oxide at a level of 50 g/kg of dry matter (DM) and brought up to a moisture content (MC) of 50% following bale grinding, and stored anaerobically at ambient temperatures for greater than 60 d prior to the feeding experiment. Eight Holstein cows were enrolled in a replicated 4x4 Latin square, where treated stover replaced corn grain on a dry mass for mass basis in the ration, at rates of 0, 40, 80, and 120 g/kg DM. With increasing stover replacement, neutral detergent fiber (NDF) concentration in the diets increased, rumen NDF turnover was not affected, and DM intake declined linearly. NDF digestibility was not affected by stover inclusion, nor were changes in NDF passage rate or the rate of digestion of potentially digestible NDF detected. Milk, fat, and protein yields declined linearly as DM intake declined. Rumen nadir pH increased linearly from 5.83 to 5.94 with stover replacement. Mole amounts of acetate, propionate, and butyrate were not affected by treatment. Treatment did not affect time spent laying, standing, eating, and ruminating. In conclusion, replacement of corn grain with calcium oxide-treated stover did not affect fiber digestibility or ruminal kinetics, but did result in reduced intake and milk production.