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ARS Home » Research » Publications at this Location » Publication #77434
Title: PERFORMANCE, RUMEN FERMENTATION, AND SITE OF STARCH DIGESTION IN EARLY LACTATION COWS FED CORN GRAIN HARVESTED AND PROCESSED DIFFERENTLY.

Author
item KATHERINE, KATHERINE - DEPT ANIML SCI-UNIV OF MD
item Glenn, Barbara
item ERDMAN, RICHARD - DEPT ANIML SCI-UNIV OF MD

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Nutrition of dairy cows influences dairy cow health and milk production. Processing of grain sources is an important way to influence the digestion of these grains by cows. Lactating dairy cows were fed diets containing corn grain that was either harvested wet and fermented before feeding (high-moisture corn) or dried before storage (dry corn). Each of these grains were then either finely ground or rolled before being added to an alfalfa silage-based ration and fed. Starch in high moisture corn was more digestible in the rumen than was starch in dry corn, and was more digestible in the small intestine as well. Improved milk yield was not observed with high moisture corn, although milk yield was increased in a companion calorimetry study. Grinding corn increased total tract starch digestibility and milk yield. Dry rolling was inadequate as a corn grain processing method for early lactation cows. Corn processing not only influences ruminal starch digestion, but also site of post-ruminal starch digestion. Improvements in digestion, metabolism, and milk yield by dairy cows can be obtained with processing of corn grain. Dairy producers should grind high moisture corn for dairy cows.

Technical Abstract: In two experiments, the effects of corn grain processing on performance, rumen fermentation, and starch digestion in early lactation dairy cows were assessed. Diets were based on wilted alfalfa silage, and high moisture or dry corn grain, ground or rolled. Thirty-four cows (17 multiparous) were used to measure effects on intake and lactational performance under commercial conditions during weeks 2-15 postpartum. Grinding increased dry matter intake, particularly within dry corn diets, and tended to increase yield of milk, protein, lactose, and SNF. Cow performance was not affected by moisture. In the digestion experiment, six cows (43 DIM) with ruminal, duodenal, and ileal cannulae were used to measure rumen and intestinal digestion. Duodenal microbial N flow was not affected by treatment. Rumen and small intestinal starch digestion were greater with high moisture corn, while large intestinal starch disappearance was greater with dry corn. Both grinding and high moisture corn increased total tract starch digestibility. High moisture corn increased rumen starch digestion, total tract starch digestion, and enhanced rumen fermentation as indicated by increased rumen VFA and decreased rumen ammonia concentrations. In the production experiment, however, only grinding corn improved performance while ensiling corn at high moisture had little effect.