Flies love to feed on and lay their eggs in an open wound. This is extremely irritating to the horse and introduces bacteria to the area, possibly even minutes after you’ve cleaned the wound. Bandaging is, of course, your best defense, but when the wound is located in an area that is difficult or impossible to bandage or bandaging is contraindicated, you need to take another strategy.
Your first step is to keep the area clean (see sidebar). A draining or infected wound is the most appealing to flies. Your veterinarian may be inclined to be more aggressive about using antibiotics on a wound during fly season due to the increased chances of infection, so be sure to let your vet know at the first sign of heavy drainage, white or yellow drainage, redness or increased pain.
Fly-spray chemicals, or products containing fly repellents or insecticides, shouldn’t be applied directly to wounds or to areas above them where sweat might wash down into the wound. Open wounds will absorb these chemicals at a much higher rate than intact skin. Basically, if you wouldn’t put it in your horse’s mouth or eyes, you won’t put it on an open wound either.
You can use a fly-repellent-containing ointment or an insecticide roll-on or wipe-on product below the wound, at least ?? inch from its edges. Liquids can also be mixed into a small amount of petroleum jelly to keep them in place. This is rarely sufficient to completely keep flies off, however. They simply ignore the treated skin and land directly on the wound.
Farnam’s Swat (www.farnamhorse.com, 800/234-2269) provides protection from flies and is also a wound ointment. It does repel flies. However, because of its insecticide, we would restrict use to around the edge of large wounds, over intact skin. Instead, you need to use a barrier product over the actual open wound.
Hydrogel Dressings: With extensive open wounds, your veterinarian may decide to provide you with a hydrogel dressing. These are gels based on collagen or other complex carbohydrates that are designed to provide a seal over the wound, which keeps the surface of the wound and the wound edges moist. Keeping the area moist reduces pain and encourages healing. These products are pricey and often only available through veterinarians, although some like Collasate ($16/1 oz. spray, www.collasate.com, 800-874-9764) are available in veterinary-supply dealers.
An alternative to these pricier gels that works well and is also hydrating and soothing is Equine America’s Skin Renovator, about $23.50 for 3.4 oz. of gel. Apply twice daily to a clean wound (www.equineamerica.com, 800-838-7524).
Sealing/Barrier Dressings: These are sprays that form a tight seal over the surface of the wound. These are most suitable for wounds that don’t involve any deep pockets where fluids can collect, for abrasions and partial skin thickness wounds. They are also good for the later stages of healing, when open wounds are granulating.
Many of the hydrogel products are also available as liquid sprays rather than gels. These include Collasate and Skin Renovator, as well as Neogen’s ClothiVet Spray, about $20/30 ml, which is about an ounce (www.neogen.com, 800-477-8201).
One of our favorites in the ”oldies but goodies” category for a sealing wound spray is Dr. Naylor’s Blu-Kote, about $7.75 for 5 ounces, available as an aerosol, dab on or pump spray. This product is available from a wide variety of retailers and is found in most tack shops and feed stores. AluSpray, from Neogen, is about $15.50 for 75 grams (2.6 ounces) and, like Blu-Kote, also forms a tight, waterproof seal that will last from several days to a week.
You may even have a good choice right in your own medicine cabinet. Bactine has excellent pain-relieving properties, as well as being a good dressing, as does the Band-Aid brand liquid bandage.
Antiseptic and Antibiotic Creams. A variety of topical creams containing ”tamed” iodine, Nolvasan, furadantoin antibiotics (the familiar, bright yellow nitrofurazone creams) and a variety of single or multiple antibiotic-containing wound creams available over the counter at any drug store can be used.
The drawbacks to these creams, and a variety of herbal or moisturizing wound creams/salves, is that dirt and other material in the environment adheres to them. They’re messy, and they don’t seal the wound as well as the products above and most do wash off easily with water or sweat. Unless your vet really thinks one is necessary, or it’s all you’ve got on hand in a pinch, we’d pass.
Wound Powders and Powder Sprays. Although they do help keep the surface of the wound dry, and therefore less attractive, these drying sprays slow wound healing and often increase pain, which can lead to the horse chewing or rubbing the wound.
Last but far from least is nature’s perfect wound bandage: a scab. If your horse’s wound forms a scab, with no drainage or excessive heat around it to suggest infection underneath, leave it alone, as a scab is ”designed” by nature to protect the wound so it can heal. To keep the edges from drying out and becoming irritated, rub in a gentle moisturizing cream like Corona Ointment, which is about $5.99 for 7 oz. (www.summitinds.com, 770-590-0600).