Submitted to: Recent Advances in Animal Nutrition in Australia
Publication Type: Proceedings
Publication Acceptance Date: 7/12/1999
Publication Date: N/A
Technical Abstract: Grain can enhance the growth of cattle, but excessive grain utilization causes a variety of problems (low ruminal pH, ruminitis, founder, liver abscesses, etc.). These problems are caused by the overgrowth of pH-resistant, starch-fermenting bacteria, and the inability of grain-fed cattle to absorb fermentation acids as rapidly as they are produced. Escherichia coli is never a predominant ruminal bacterium, but it can be found high numbers in the colon if starch bypasses the rumen. E. coli has a life cycle that involves growth in fecal material as well as the intestinal tract, and to complete this cycle E. coli must be able to survive the low pH of the gastric stomach (extreme acid resistance). The extreme acid resistance of E. coli can be triggered by grain-dependent increases in colonic volatile fatty acids (VFA).