Question
Eddie is my 10-year-old Thoroughbred gelding that does some low-level eventing. He’s in moderate body condition—I’d say a 5 on the 1-9 Henneke scale—but I think he needs to gain a little weight. He has allergies and a panoply of gastrointestinal problems: gastric ulcers, hindgut acidosis, leaky gut syndrome, and occasional colic. He is jazzed mentally when under saddle—lots of energy! He spends 15 hours each day in a stall and the remainder turned out. Eddie has round-baled grass hay when he’s outside and timothy hay in a slow-feed haynet when stalled. He also gets timothy pellets (1 lb or 0.5 kg) and rice bran pellets (0.5 lb or 0.25 kg) daily. With this diet, however, he has an ongoing issue with ulcers and gas colic. The vet blood-tested him for allergies, revealing he is allergic to oats, soy, flax, sunflower, and cottonseed. His ulcers are problematic at all times, it seems, and he is itchy right now with the addition of rice bran. Looking for any feeding suggestions.
Answer
The situation with your gelding is challenging. If you can find solutions to the gastrointestinal issues, supporting weight gain may be easier. Has your veterinarian treated Eddie for gastric ulcers, and if so, has Eddie been scoped to ensure that the ulcers have resolved? Have you tested the hay to determine the nutrient content? Poor-quality forages can contribute to gastrointestinal tract issues, and high nonstructural carbohydrate (NSC) content may contribute to hindgut acidosis.
Providing a complete and balanced diet is important to support overall health and that includes a strong immune system. The immune system has a high demand for protein and amino acids, so supplemental amino acids may be beneficial when a horse is fed a hay-based diet but a high-protein ration balancer or a traditional feed is not suitable. Synthetic amino acid supplements are available that provide both essential and branched-chain amino acids. Further, supplementation with a vitamin and mineral supplement would be beneficial for Eddie to help meet basic nutrient requirements. However, it may be worthwhile to further investigate the results of the serum allergy testing, particularly regarding food allergies.
The use of serum allergy testing is convenient for veterinarians and horse owners alike. A blood sample is collected and sent off to a laboratory and, after testing, the laboratory generates a report of potential allergens, usually including several feeds or feed ingredients. Horse owners then try to concoct a diet that omits all potential allergens. Because some of these lists can be quite lengthy and include ingredients common in many high-quality feedstuffs, this exercise can become cumbersome, even impossible, to complete.
Unfortunately, however, serum allergy testing often leads to false positives for food allergies in horses, and more extensive investigation of any potential allergies would be necessary to develop a suitable diet. For example, horse owners are sometimes concerned that their horses are allergic or have a sensitivity to dietary soy. While soy is a common allergen in humans and dogs, soybeans and soy ingredients typically do not elicit allergic responses in horses. Further, since a flax allergen has been added to the panel of many serum allergy tests, results almost always come back positive for some level of allergic response to flax, which leads one to question the validity of the results. Actually, food allergies in general are uncommon in horses; allergy symptoms are much more commonly caused by environmental factors.
The better, though more inconvenient, way to diagnose potential food allergies or sensitivities is to perform an elimination diet. All suspected feeds and supplements must be removed from the ration, and if symptoms resolve within 4-8 weeks, then a food allergy or sensitivity may be present. To determine which ingredient is the potential allergen, feed ingredients and supplements should be slowly added back one at a time (over 3-6 weeks) until clinical signs reappear. If clinical signs do not reappear, then the original condition was not due to dietary ingredients.
While an elimination diet is the appropriate first step to address the allergy symptoms, it would be helpful to know additional details to help determine an appropriate ration to meet Eddie’s needs.
How much hay Eddie is consuming daily (if you can estimate the amount provided by the round bale)? Is he an enthusiastic hay eater, cleaning up the hay offered when stalled? Is the slow-feed hay provided to help reduce waste? Maximizing the quality and amount of grass hay he consumes will help with overall weight maintenance. Good-quality alfalfa hay would add calories to his diet, but it may cause increased gas, similar to beet pulp, as it is highly fermentable. Have you tried alfalfa?
Adding oil to the diet will also increase the energy density of the diet. If a food allergy is actually present,oils are very unlikely to elicit an allergic response. Plant oils are usually quite palatable, and an oil that provides a balance of essential fatty acids, such as canola oil, will supply additional calories and may possibly help with the digestive tract and allergy symptoms Eddie is exhibiting. If you prefer to avoid all the feed ingredients with positive results on the serum allergy test and still need to provide additional calories for Eddie, adding a grain such as barley or a pelleted feed based on wheat middlings (formulated without the ingredients you are avoiding) will provide a higher caloric density than hay or hay pellets.
Addressing Eddie’s digestive health will also help with weight management and strengthen his immune system. Are there environmental factors beyond diet that may be contributing to his digestive health issues?
Kentucky Equine Research has a new product, ReSolvin EQ, which is a blend of long-chain omega-3 fatty acids (EPA and DHA) and the anti-inflammatory omega-6 fatty acid (GLA) that has been shown to improve gastric health, as well as the health benefits from EPA and DHA for immune and allergy support. EO-3 is another product that supplies just EPA and DHA and can be fed at 1-2 oz (30-60 mL) per day. To address the hindgut acidosis, consider EquiShure, a time-released buffer that helps stabilize the pH of the cecum and colon.
