Avoid feeding asthmatic horses round bales, which are notorius for being dusty in the middle. | iStock

The do’s and don’ts of feeding horses with 4 common health conditions

The sneezy, runny-nosed gelding in the barn sleeps on special dust-free bedding. A laminitic pony next door wears custom wedged shoes, and the ulcer-prone Thoroughbred across the aisle lives on a panoply of medications. Veterinary care, pharmaceuticals, and management play crucial roles when addressing disease. But we often overlook an equally powerful player: nutrition.

Many studies have proven a direct link between diet and disease in horses. Moreover, research shows many maladies have a nutritional component, meaning adjusting the diet can improve the condition. Here we’ll describe feeding practices that can help—or hinder—horses with four common diseases.

1. Gastric Ulcers

For decades scientists have known that stomach ulceration is prevalent in horses of all disciplines (McClure et al., 1999). Racehorses top that list, with up to 80-100% of those actively racing having gastric ulcers (Sykes et al., 2015). Even pleasure horses get ulcers—as many as 40-60% are affected. Luckily, we can adjust the diet to help. What to feed:

Free-choice forage Unlike humans, horses continuously secrete digestive enzymes and acidic juices in the stomach, including hydrochloric acid—a compound corrosive to eyes, skin, and mucous membranes. Horses have evolved to consume small amounts of fiber-based feeds around the clock, justifying this constant gastric fluid production. Offering free-choice forage helps prevent ulcers because fiber helps buffer the acidity. Otherwise, in the absence of feedstuffs to digest, gastric juices have nothing but the stomach lining itself to break down, leaving it inflamed, eroded, and ulcerated.

Alfalfa This and other legume hays are valuable sources of protein and calcium, making them particularly effective at buffering the stomach from its own acidic contents. Researchers have shown feeding alfalfa can help prevent and manage gastric ulcers (Lybbert, 2007).

Gastroprotective supplements Choose those backed by science, and offer them judiciously based on your vet’s advice.

What to avoid feeding:

Lots of concentrates Feeds high in nonstructural carbohydrates (NSC) increase volatile fatty acid (VFA) production. While VFAs are essential for fermenting fiber in the hindgut (the cecum and large colon), an abundance of VFAs in the foregut damages the stomach’s protective mucosal lining, leaving it prone to inflammation and ulceration (Nadeau et al.,