Question
I have a five-year-old Quarter Horse-cross gelding—1,200 lb (545 kg)—that I suspect is allergic to Bermudagrass hay, in addition to seasonal allergies. Though he has no visible hives or respiratory issues, he itches to the point of creating sores. Sweet itch has been ruled out. I also believe he might be insulin resistant. I live in Arizona, and the only hay choices I have are alfalfa (lucerne) and Bermudagrass. Are Bermudagrass allergies common? Is there any way to control the allergies?
Answer
If your gelding has insulin resistance (IR), I would recommend having your hay tested for nonstructural carbohydrate (NSC) content (starch and sugars) to help you select the most suitable hay containing <10-12% NSC. If weight gain is not an issue, then you may consider adding more alfalfa into his diet and reducing the amount of Bermudagrass to help with his allergic reaction, as long as NSC levels are appropriate. Alfalfa is usually not recommended for horses that have insulin resistance because of the extra calories alfalfa provides compared to typical grass hays. Most horses with IR are easy keepers prone to weight gain.
To help treat and manage your gelding’s allergies, I would recommend discussing with your veterinarian the option of using corticosteroids and antihistamines. Daily supplementation of omega-3 fatty acids can help modulate the immune response to allergens, reducing the severity of allergic reactions. Marine-derived sources of EPA and DHA have been found to be more biologically potent than plant-based sources of omega-3 fatty acids (alpha-linolenic). I would recommend supplementing with a marine-derived supplement, such as EO•3 at 2-4 oz per day, to help reduce inflammation and hypersensitivity that may be causing his itchiness.
Many owners think horses have feed allergies when the cause is actually other factors in the horse’s environment. Blood tests are not an accurate way to assess feed allergies. The best way to identify a food allergy is through an elimination diet; however, as you are limited in the types of hay available, this makes it more than likely that Bermudagrass hay will eventually be part of your horse’s diet. One way to significantly reduce the level of contaminants in the hay (mold spores, pollen, dust, and bacteria) is by soaking or steaming the hay prior to feeding. Soaking for 10-30 minutes in hot water or 30-60 minutes in cold water can have a beneficial effect on reducing both the amount of contaminants and water-soluble sugars in the hay.
A more in-depth review of allergies in horses can be found in the article Food Allergy in the Horse: A Dermatologist’s View, published in Advances in Equine Nutrition IV from Kentucky Equine Research (KER).
