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 horse's 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. An individual's 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 fed as concentrated ration. Another measure would be no more than 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. Contributing factors to the high incidence of colonic ulcers is the reduction of ph in the colon caused by concentrate rations. This reduction in ph can lead to the 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. Recent clinical research has uncovered the following theories regarding sand and silt:
- Many horses that are non symptomatic are accumulating some quantity of sand and silt in their colon, and may be suffering from irritation and ulceration.
- Many horses, besides just those exhibiting signs of colic, are suffering with motility disturbances due to sand and silt accumulation.
- Fecal sand examination may not accurately assess a "sand problem" as those horses accumulating sand may not expel sand in their feces.
- Establishing a positive environment for hind gut bacteria may improve motility, and thus aid in the removal of sand and silt from the colon.
- Combining appropriate levels of pre and probiotics and adequate quantities of psyllium appears to be the most reliable method for improving colonic motility and removing all sand accumulations.
The following list of management practices, centered on good nutrition can significantly improve your horse's digestive health and create a healthier horse:
- Feed at least 60% of the daily ration as forage (hay or pasture).
- When possible, pasture in non-irrigated fields, and/or use a grazing muzzle to control weight and intake of rich forage.
- Limit the quantity of grains fed.
- Substitute high-fat feeds and high-fiber feed for grain supplements.
- Provide feeding systems that limit the intake of sand and dirt.
- Consider a program of supplementation that improves digestion and motility and removes sand and silt accumulation.
- Provide plenty of turnout and exercise each day.
- Provide clean, ice-free drinking water.
- Implement regular and frequent deworming programs for the herd.
- Minimize stress (transport, herd dynamics, housing, illness, injury) as much as possible.
Most modern equine diets contain enough calories to support your horse if feeding a high quality concentrated feed. In most cases a combination of pasture, dry forage and concentrate will supply all of the nutrition needed by your horse. Remember that digestive health is critical to the general wellness of your horse. Preventing colic is better for your horse than treating colic; therefore managing your feeding program will pay off when it comes to the health of your horse.
Jay Altman, DVM
Equine Research Associates, Ltd