CHEMICAL TREATMENT OF GROUND CORN TO LIMIT RUMINAL STARCH DIGESTION

Abstract

Five trials were conducted to determine the effects of chemical treatment of ground corn on in vitro dry matter disappearance (IVDMD), in vivo nutrient utilization and ruminal starch digestion. Ground corn was treated with 0, 1, 2 or 3% (wt wt−1) formaldehyde, glyoxal, masonex, propionaldehyde or tannic acid. IVDMD of ground corn was inversely related (P < 0.01) to percent formaldehyde treatment level, while glyoxal, masonex, propionaldehyde and tannic acid were relatively ineffective in reducing IVDMD. Treatment of large batches of ground corn with 0, 0.5 or 1% (wt wt−1) formaldehyde also linearly reduced IVDMD (P < 0.01). Six abomasally fistulated wethers (average weight 95 kg) were used in a replicated 3 × 3 Latin square to determine the effects of 0, 1 or 2% (wt wt−1) formaldehyde treatment of ground corn on ruminal and total tract nutrient digestion. Ruminal dry matter (DM) digestion and total tract DM, organic matter (OM) and acid detergent fiber (ADF) digestion decreased linearly (P < 0.01) with increasing formaldehyde treatment levels. Ruminal starch digestion decreased 30% and 41.5% for 1 and 2% formaldehyde treatment, respectively, compared to untreated corn while total tract starch digestion was not affected (P > 0.05) by formaldehyde treatment level. Results of these trials are interpreted to suggest that formaldehyde treatment of ground corn reduced rumen microbial digestion of starch both in vitro and in vivo without reducing total tract starch digestion. Key words: Corn, starch digestion, formaldehyde, ruminants