Page 127 - April2022

VETERINARY VIEWS
For every pound of feed ingested, a horse needs 2-4 pints
of water for digestion. This means that a 1000-pound horse consuming 20 pounds of food each day needs a minimum of 7.5 gallons (or 30 liters) of water to process the feed material.
solid phase change (e.g., larger particle size, increased particle stiffness) in a way that makes formation of a hard mass (i.e., an impaction) even more likely.
Poor dentition also increases the risk of impaction by compromising mastication, which leads to a situation similar to what
is seen with ingestion of poor-quality roughage: poor chewing results in intake
of larger particles. Thus, regular dental care is recommended.
LIFE-STYLE EFFECTS ON INTESTINAL FUNCTION
Alterations in motility, the water content within the colon, and changes in exercise are all considered as possible risk factors for colic. Events associated with an impaction include recent management change within two weeks prior
to signs. One of the most frequently reported management changes is sudden restriction of exercise due to a musculoskeletal injury including hospitalization or restriction of exercise after surgery. Recent stall confinement is associated with about 54% of impaction colic cases; another study notes that 62% of colon impactions occur within two weeks of significant management changes, such as stall confinement or transport.
Confinement may have multiple adverse effects on equine intestinal function. Stall-confined horses often experience inconsistencies in feeding intervals and amounts relative to previous management habits. The period of increased risk occurs when an active horse that has had regular exercise or turn out is suddenly confined to a stall. Ingestion of indigestible non-feed material such as shavings, sand, gravel, hard seeds, hair, pieces of rope or twine, rag and pieces of rubber can also lead to GI impaction. Although most horses would not eat these materials, some may develop vices or may be prone to strange eating behaviors due to conditions such as prolonged stall confinement or hunger. Thus, the time horses are kept in stalls should be minimized.
Ideally, horses confined to a stall should not be fed grain, as energy is rarely needed. During periods of confinement or transport, use of bran mashes or other diet alterations has not been proven to prevent impactions. Additionally, feed modifications and diet changes have been incriminated in causing colic.
Exercise incurs multiple benefits by increasing metabolism and improving intestinal motility. When possible, free choice exercise is best for horses, as some exercise appears to favor normal digestive processes with frequent intake of small amounts of feed over time. Just as changing the diet can be a challenge to some horses’ digestion, horses with sudden decreases in activity should be monitored closely for digestive problems that can lead to colic. Light physical activity like walking stimulates GI motility. Fiber digestibility increases by up to 20% in exercised horses, promoting greater retention of the fluid part of the diet
and shortened retention of the more formed, particulate part of the feed. Progressive movement of particulate materials down the intestinal tract promotes efficient digestion while not allowing it to linger to form dehydrated intestinal contents.
Feeding in the period surrounding exercise is not without its own set of problems. Rigorous exercise just prior to feeding may decrease feed digestibility while blood remains shunted to working muscles, away from the intestinal tract. Strenuous exercise will shut down intestinal motility, so it makes sense to limit the amount of feed in the stomach or small intestine during exercise. Feeding forage at intervals during moderate or light exercise is appropriate. Take proper measures to adequately cool
out a hot horse before feeding large meals, particularly grain.
MAINTAINING NORMAL MOTILITY: SUMMARY
Optimal equine health is based on normal intestinal activity and motility.
• Feeding a diet of at least 50-60% fiber (hay, roughage, pasture) achieves optimum intestinal function.
• Minimize the amount of grain or supplements fed, as these tend to be highly fermentable materials as well as contributing to possible consequences of gastric or colonic ulcers, laminitis, and poor behavior.
• Deworm on a regular basis based on fecal egg counts to minimize the intestinal parasite load.
• Provide plenty of clean water at all times. • Regular exercise encourages drinking,
appetite, and intestinal motility.
• Take care of dental needs once or twice
a year so a horse adequately chews his feed to derive the most nutrients and to minimize intestinal irritation.
• Monitor a horse’s daily manure output as well as feed intake. Observe the form, consistency, and quantity of the fecal balls, and know what is normal for each individual.
Catching a problem while it is yet a small issue helps to prevent it surfacing into a full-blown colic.
NEXT TIME
In the next installment, we will discuss Muscle Disorders. Stay tuned.
According to studies, 54% of impaction colic cases are due to new or recent stall confinement; and 62% of colon impactions occur within two weeks of significant management changes, such as stall confinement or transport.
Changes in motility such as a sudden restriction of exercise due to a injury, including hospitalization or restriction of exercise after surgery, is a possible risk factor for colic.
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