Roughage Levels in Feedlot Rations

vitro digestibility tended to be greater with ammoniation. In the second trial, very high levels of ammonia, urea or glucose were added. Levels of insoluble protein were much higher in this trial than the other. This reflects the high variability of corn silage. Recovery of nitrogen added as ammonia averaged 82 percent while all of the nitrogen added as urea was recovered. The amounts of insoluble crude protein present increased similarly with addition of both urea and ammonia. Addition of soluble carbohydrate (glucose) had no effect on insoluble protein content. Results suggest that NPN addition to corn silage may increase the content of insoluble, potential bypass protein. Whether this increased insoluble protein does escape ruminal digestion remains to be proven. A number of feeding studies froin Michigan with ammoniated corn silage suggest that ammoniated corn silage is used more efficiently by cattle. If increased protein bypass is responsible, ammoniation should prove most useful for starting cattle fed low protein rations.