Humans and horses have different digestive tracts and eat different foods (feeds), but there are similar food-related medical problems in both species.  In humans, similar clusters of metabolic symptoms called Syndrome X, The Metabolic Syndrome, The Dyslipidemic Syndrome and The Insulin-Resistance Syndrome are being studied¹.  Similar syndromes have been reported and named in horses.  Unfortunately, most of these terms do not clearly describe the disorders or offer clues to possible management strategies. 

The term EGA for Equine Grain-Associated Disorders was recently introduced to describe common feed-related syndromes in horses².  Subsequently, Dr. Kronfeld of Middleburg Agricultural Research and Extension Center at Virginia Polytechnic Institute and State University, explained the history and etiology of the various human and equine syndromes, offered EGAD as a less confusing name and provided some management suggestions to reduce these problems in horses¹.  Following is a summary of his findings. 

In 1988, endocrinologist Gerald Reaven suggested that a high-(soluble) carbohydrate diet aggravated or exacerbated insulin resistance leading to obesity, type 2 diabetes mellitus, hypertension and coronary heart disease in humans.  His suggestion opposed the then-current American Heart Association’s recommendation for a low-fat (high-carbohydrate) diet to reduce heart disease.  Syndrome X factors were identified as: insulin resistance, hyperglycemia, elevated plasma VLDL triglyceride level, low plasma HDL cholesterol level and hypertension. 

In 2001, Dr. Kronfeld used the term Equine Syndrome X for equine disorders associated with long-term consumption of grains and molasses, which involved insulin resistance.  Meals of grains and molasses set up an unnatural feeding-fasting cycle of plasma glucose, insulin and counter-regulatory hormones in horses.  As an alternative, he reported that meals of fat and fiber do not produce these feeding-fasting cycles.  Fat and fiber meals also reduce episodes of tying-up in horses with Recurrent Exertional Rhabdomyolysis (RER) and Polysaccharide Storage Myopathy (PSSM)¹. 

The term Equine Grain-Associated Disorders is used to describe both digestive and metabolic disorders in horses.  The digestive disturbances involve rapid carbohydrate fermentation and insulin resistance, including some forms of colic, colitis, diarrhea, gastric ulcers and laminitis.  The metabolic conditions include some forms of gastric ulcers, laminitis, exertional rhabdomyolysis (tying-up), osteochondrosis, growth rate fluctuations, flexure deformities, hyperlipidemia, oxidative stress, aging, obesity and, possibly, abortion.  Some of these risk factors might be nonessential but contributing factors to the disorders¹. 

Dietary recommendations for horses include:

1) avoiding high glycemic feeds such as ‘sweet feed’ and oats, which produce increased blood sugar after meals and

2) avoiding unprocessed corn and high-fructan pasture grasses, which provide highly fermentable carbohydrates to the large intestine¹. 

Colic is still the number one killer of horses, and laminitis is one of the top three most feared by horse owners.  Tying-up, gastric ulcers, developmental orthopedic disease, cribbing and other disorders listed above have all been associated with repeated feeding of starches and sugars to horses.  To address these concerns, ADM Alliance Nutrition is the leader in the production of feeds and supplements formulated with added fat and digestible fiber and low starch and sugar (Table 1).  These feeds provide sufficient nutrients for maximum performance, growth and lactation, while reducing the risks of EGAD.  For comparison, corn, barley, molasses and oats contain about 71, 65, 63 and 53% NSC (starch, sugars and pectins), respectively.  Be sure to check your feed labels and call the manufacturer if you have questions about the nutrients in your horse’s ration. 

¹Kronfeld DS. Equine Syndrome X, The Metabolic Disease, and Equine Grain-Associated Disorders: Nomenclature and Dietetics. J. Equine Vet. Sci. 23(12):567-569.

²Kronfeld DS, Harris PA. Equine Grain-Associated Disorders (EGA). Compend. Contin. Edu. Pract. Vet. 2003.

Table 1. FORAGE FIRST^® Low-Starch Horse Feeds and Supplements

*S&S estimate of starch and sugar content of a feed. 

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