Insects can make your horse's life miserable. Spring brings those annoying little no-seeums, summer the bird-sized horseflies, and fall the little biting flies that draw blood.
Your horse's tolerance for flies may depend on his breed, color and temperament. Thin-skinned thoroughbreds have a tough time, while quarter horses seem to tolerate the bugs better. Dark-colored horses seem to suffer more from insects than those with light coats because some flies are attracted to dark colors. Whatever color or breed your horse is, he will appreciate a little prevention on your part to make his life insect-free.
Change Your Horse's Routine
The best defense against flies is to avoid them. If you can, turn your horses out overnight when it's warm enough – usually by mid-May. Horses learn quickly that cool, dark nights are fly-free. Until the weather gets really hot, they also can stay out during the day. As the heat increases, so do the flies. Then the horses will appreciate lounging in their stalls for at least the afternoon hours. During the 'dog days' of summer, bring them in for breakfast and leave them in until after they've eaten dinner. Some insects bite only at dusk, so you have to adjust your horse's turnout to the local pests' biting habits.
There are many sprays to choose from, with some containing traditional chemical insecticides, and several made from 'natural' ingredients.
Traditional insecticides that are safe for horses include pyrethrins, permethrins (the synthetic form of pyrethrins) and malathion. Pyrethrins were originally extracted from flower heads of the chrysanthemum, as one of the many natural defense chemicals of flowers. But like the venus fly trap, however, it was too expensive to cultivate, so now it is largely manufactured synthetically. However, due to its natural origins, the pyrethrins are very safe. They act by paralyzing insects, who then learn to stay away from the chemical. Many insects appear to tolerate pyrethrins, although it may be that the chemical is not applied frequently enough or gets washed off with sweat.
There are a whole host of "natural" products. These products are made from various natural spices and chemicals. For example, Nature's Defense, made by Farnam, uses a combination of citronella, cloves, commint and thyme. It smells good and is affordable because it's concentrated so you mix it yourself. Absorbine also makes an herbal spray called SuperShield Green, but it doesn't come in a concentrate, so it's not as cost-effective. There are a number of others in the equine catalogs, along with the typical chemical sprays that generally are more expensive, less healthy and don't smell as good.
It's important to keep in mind that these products do not undergo any rigorous clinical trials, so you're taking a chance that the claims on the bottle are not proven. This is especially true for the natural products that have a shorter product history, so you can't necessarily find someone who has used it for a while and can give you a firm recommendation.
While fly spray should be a component in your horse's defense against flies, mosquitoes and ticks, it should not be your only defense. When the weather heats up and your horse sweats, the chemicals just roll off the horse as if he went for a swim. The heat also increases the rate with which the fly spray evaporates. If it rains, fly spray again washes off. And if your horse rolls – especially in muddy fly-attracting dirt – your fly spray is history. On top of that, insects become resistant to fly spray after constant use. Rotating brands can be effective – but only for a while. The best time to apply fly spray is before taking a ride or during a horse show, but it won't help win the battle all day.
Several "natural" remedies work well to augment fly spray. A combination of brewer's yeast, garlic and apple cider vinegar provides an effective deterrent to flies and ticks. Brewer's yeast can be purchased in any health food store, along with apple cider vinegar. Don't even bother with the kind of apple cider vinegar you find in the supermarket – it's little more than colored water. If you don't have time to crush your own garlic, you can buy it pre-crushed in jars. You should mix roughly one clove of garlic once a day in your horse's food (approximately 1/8 teaspoon crushed); add one-quarter cup of apple cider vinegar to his water or food and top dress with Brewer's yeast per the instructions on the jar.
There also is a product called "Bug Off Garlic," which is made by Springtime, Inc., a manufacturer of natural supplements for pets and people. This product is made entirely from pure garlic powder rather than fillers that can dilute its effectiveness. The manufacturer says that it also can be sprinkled around the stall and in feed bins to keep bugs away.
For those who prefer the convenience of ready-made, a mail order company named Cheval makes a product called "Inside Out Insect Control" that combines all three ingredients in a powder that you top dress on your horse's food. Nothing attracts flies like manure, and to avoid that situation, Farnam manufactures Equitrol – a feed-through pelleted supplement that wards off flies. Flies that would normally be attracted to your horse's manure and lay their eggs are repelled. This can be found in your local feed store or in catalogs.
A fly mask is a must if your horse is turned out at all during the day. They work by shielding the face around the eyes, leaving the muzzle free. This is highly effective because the moisture of the eyes is the greatest attractor of flies. In fact, some flies choose to lay their eggs in the eye, and this can result in eye damage when the larvae hatch, migrating through the eye. The mask denies access of these flies to the eye altogether.
Admittedly, they look ridiculous, but they do the job and help prevent infected eyes and cranky horses. Masks are available in a variety of types, with or without ears. Some horses' ears are more sensitive to insects and for them the masks with ears provide extra protection. Make sure you don't put the mask on too tight, though – after months of wear, they will chafe the horse's nose. The amount of sunlight restriction caused by the mask is minimal, so it cannot be counted on as "sunglasses" for headshakers that are sensitive to the sun.
If your horse is a dark color, a thin-skinned thoroughbred sensitive to bugs, or has a coat that bleaches in the sun, you may want to use a fly sheet. Fly sheets have progressed by leaps and bounds from the days when you could find them in only one color, and they looked – and fitted – much like sweat sheets. These days, the well-dressed horse can sport a plaid fly sheet with a matching mask and leg wraps. Of course, he may be a bit embarrassed to be seen by his pals, but at least he won't have welts from the bugs.
One of the best inventions in recent years is the Fly Wrap™. If your horse spends a lot of time stomping his feet because the flies bother him, these fly wraps are worth their weight in gold. Most farriers agree. The more your horse stomps, the faster his shoes get loose, and the more shoes he loses.
Even in the heat of summer, a fly sheet provides welcome relief for some. Look for the same type of features that you would in a winter turnout blanket – secure leg straps and surcingles – so the sheet doesn't shift or slip if the horse rolls. A ripstop fabric is important, too, especially because fly sheets are made of much lighter mesh than regular blankets. A good quality fly sheet that will last several seasons may cost more than $100, but it's worth the investment. Those you will find priced for less than $50 won't survive a good scratch on the fence post.