Without an efficient, healthy gastrointestinal tract, horses cannot perform their best, no matter if you own a cherished broodmare and her latest produce, a string of high -performance horses, or a single pony for your grandchildren to enjoy.
When considering gastrointestinal health, every part of the digestive tract is relevant, from one end to the other. Nutritionists have been most focused on two specific areas of the gastrointestinal tract, the stomach, and the hindgut. The hindgut is a collective term that includes both the cecum and the colon, and houses a diverse and symbiotic microbial population that contributes significantly to fiber digestion.
Horses rely on fermentation for optimal digestion of feedstuffs and energy production. Hindgut digestion progresses most efficiently when horses are allowed continual access to forage and limited access to feedstuffs that could upset the pH of the cecum, including large grain meals.
Fermentation is achieved through the machinations of billions of protozoa, fungi, and bacteria. Together, these microbes convert carbohydrate-based contents, essentially plant-based fiber, into volatile fatty acids, which provide energy to the horse. If soluble carbohydrates , such as those found in large supply in grain meals, find their way into the hindgut, some lactate might be produced.
Overproduction of lactate can shift the pH of the hindgut to a more acidic state, which may cause problems. When a drop in pH occurs, called hindgut acidosis, some of the beneficial fiber- digesting microbes die off, and digestive efficiency drops.
One of the primary signs of hindgut acidosis is decreased appetite. A horse is often reported to be “off its feed.” Because the hindgut is overwhelmed with lactic acid when a horse is experiencing acidosis, the intestinal lining becomes inflamed and irritated, causing the horse discomfort. The irritation may be severe enough to induce behavior characteristic of colic.
Furthermore, and perhaps most detrimental to equine athletes, is a reduction of feed efficiency. Long-term exposure of the intestinal lining to a low-pH environment may negatively affect the absorptive capacities of these structures, limiting the amount of energy available for performance.
In addition to these health concerns, a link between hindgut acidosis and stereotypies such as wood chewing, weaving, and stall walking has been suggested by researchers. Because of the precarious nature of the hindgut of a horse afflicted with subc linical acidosis, it is less able to handle metabolic crises that healthy horses may be able to fend off. Hence, horses with hindgut acidosis are more susceptible to colic and laminitis.
To offset the risk and subsequent symptoms of hindgut acidosis, horse owners should scrutinize feeding management. Hindgut acidosis is rarely caused by what is fed but rather how it is fed. Here are three strategies to ward off hindgut acidosis:
• Good-quality forage should be offered at all times so that the hindgut is continually in “processing mode.” Forage may be pasture, hay, or hay-based products such as cubes or pellets. Forage selection should be based largely on the nutrient needs of the horse.
• Concentrate meals should not exceed approximately 0.5 lb (0.23 kg) per 100 lb (45 kg) of body weight (5 lb for a 1,000-lb horse; 2.25 kg for a 450-kg horse).
• If a horse requires more than 5 lb (2.25 kg) of concentrate per day, divide total daily allotment into separate meals. Feeding three or four concentrate meals, evenly spaced throughout the day, is more beneficial to the horse than huge meals.
Some horses, especially those that are asked to perform intense exercise, must consume large grain meals to fuel performance. Research supports the use of a hindgut buffer in cases of high- grain and high-fructan intake. EquiShure®, a time-released buffer developed by Kentucky Equine Research, supports a stable microbial environment and is proven to raise the pH of the hindgut and eliminate signs of acidosis.
Learn more about science-based digestive health supplements offered by Kentucky Equine Research at ker.com.
Kentucky Equine Research is an international equine nutrition, research, and consultation company serving horse owners and the feed industry. The company advances the industry’s knowledge of equine nutrition and exercise physiology, applies that knowledge to produce healthier, more athletic horses, and supports the nutritional care of all horses throughout their lives. Learn more at ker.com.
