Most horse owners realize that one of the keys to a healthy horse is their feeding program. Not only are high quality feedstuffs important for the horses overall health, but feeds, feeding practices, feed mixtures, feed contaminants and stress all contribute to gastro-intestinal condition. Most recently there has been considerable discussion and research regarding digestive health. It is well accepted that many horses in work, especially those expending high levels of energy need concentrated rations to supplement the energy they can obtain from forages. The higher calorie concentrated rations create a shift in not only the percentages of energy derived from complex sugars and cellulose, but also in the percentages and types of volatile fatty acids (VFAs) and other fermentation products related to the digestion of the soluble carbohydrates in the concentrated feed. The consequences of these shifts can be gastro-intestinal disruption leading to gastric and colonic ulcers, as well as a destruction of the vital micro-organisms needed for optimal digestion, production and absorption of nutrients.
The amount of concentrated feeds and simple sugars that can cause these conditions is variable and an individuals genetics as well as the management practices that the individual is subject to will in part dictate the "threshold" for that individual. Most veterinarians and researchers recommend that no more than 40% of the horse's daily ration be feed as concentrated ration. Another measure would be no more that 5 pounds per day for a horse averaging a body weight of 1000-1100 pounds. Many horses in competition and or "heavy" work require between 1-2 pounds of concentrated ration per 100 kilograms or 220 pounds of body weight. As these horses move into the range of 5-10 pounds of concentrate per day their susceptibility to the ill effects of this feeding method increase significantly.
The high incidence of gastric ulcers in horses has been in the forefront of performance horse medicine over the past 10-15 years. Some of the most recent research has started to reveal the alarming percentages of horses suffering with colonic ulcers as well. Some of the additional contributing factors to the high incidence of colonic ulcers are the reduction of ph in the colon with the ensuing destruction of "good" bacteria and the proliferation of pathogenic strains. Further complicating the picture is the irritation and ulceration that can be caused by sand and silt accumulation in the colon. Additional new research has uncovered the following theories regarding sand and silt: