According to a recent survey*, most horse owners or caretakers have a good knowledge of the basics of equine nutrition. They are, however, less sure of how dietary requirements change if a horse is diagnosed with a nutrition-related disorder.
Because of this chink in the armor, the survey authors suggested that educational efforts should be directed towards five specific nutrition-related disorders.
1. Insulin resistance This is a term used to describe horses and ponies that do not respond normally to the effects of the hormone insulin.
“Weight loss is one of the most important ways to help manage horses or ponies with insulin resistance,” advised Kathleen Crandell, PhD, a nutritionist at Kentucky Equine Research.
Offer hay-based diets (at approximately 1.5% of body weight rather than 2–2.5% body weight) and have the hay analyzed to ensure the hay contains less than 8% water-soluble carbohydrates (sugars). Hay soaking might also be beneficial to decrease the sugar content of the forage. Do not offer high-sugar treats or concentrates. Monitor fat deposits, body weight, and body condition regularly and ensure your horse exercises for approximately 30 minutes per day.
2. Equine Cushing’s disease Caused by a tumor in the pituitary gland located at the base of the brain, affected horses suffer from excessive drinking and urination, sweating, poor hair coats that do not shed normally, degeneration of skeletal muscles resulting in a pot-bellied appearance, and often chronic or ongoing painful, life-threatening bouts of laminitis.
“Similar to insulin-resistant horses, those with Cushing’s disease should be maintained primarily on forage with a low content of water-soluble carbohydrates (sugars),” Crandell shared. "Treats and concentrates should be avoided. If extra calories are needed to maintain condition, try using fat (e.g., vegetable oil) instead of sugars. Because Cushing’s occurs more frequently in older horses, carefully read the label of any senior formulation to check the sugar content, sometimes hidden in the form of molasses."
3. Recurrent equine rhabdomyolysis Most often referred to as “tying-up,” this is a very painful condition that results in muscle cramping and muscle damage. It is caused by the abnormal regulation of calcium during muscle contraction and exercise.
“Research in this field found that horses fed a diet lower in grain, and therefore lower in soluble carbohydrates and sugars, and higher in fat is preferable for horses prone to tying-up. Medication may also be necessary in some cases,” advised Crandell.
4. Equine gastric ulcer syndrome A horse’s stomach has a sensitive section that is prone to ulceration. Again, medications are available that can help affected horses; however, dietary changes can do a lot to prevent and repair ulcers. High-grain diets and periods of fasting, even a few hours, increase the occurrence of ulcers. Therefore, offering free-choice forage to ensure a horse’s stomach is rarely empty can help minimize the occurrence of ulcers. Using anti-grazing muzzles to slow forage consumption may also be a viable option.
5. Recurrent airway obstruction Frequently called heaves or COPD (chronic obstructive pulmonary disease), airway obstruction is similar to asthma in humans. Affected horses are exercise intolerant, have a cough and nasal discharge, mucus in the airways, and labored respiration. It is an all too common condition that can be improved by keeping horses on pasture as much as possible and avoiding exposure to inhaled particles. To this end, spreading hay on the ground to promote mucus drainage, soaking or steaming hay to reduce inhalation of dust and mold, and respecting the two-foot sphere around the horse’s nose at all times (the breathing zone) can make a huge difference in the life of a heavey horse. Omega-3 fatty acids are also recommended.
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*Murray, J.D., C. Bloxham, J. Kulifay, et al. Equine nutrition: A survey of perceptions and practices of horse owners undertaking a massive open online course in equine nutrition. Journal of Equine Veterinary Science. In press.