As you slather on the sunscreen this summer, don't forget that your horse can get sunburned, too, particularly if he has pink skin,which has less protective pigment (melanin). Here's how to shield him from the sun's ultraviolet radiation
Use protective "clothing." Several companies make sun-blocking fly sheets, masks, hoods, wraps and other garments. If your horse has a blaze, snip or other white markings on his muzzle, look for a fly mask with a flap that extends down the nose.
Apply sunscreen or sunblock products.Physical sunscreens (also referred to as sunblocks), such as zinc oxide ointments, create a barrier against the sun's rays. Because these products are thick and gooey, they are usually easiest to apply to hairless areas such as the muzzle. Chemical sunscreens, on the other hand, filter out only specific light wavelengths, allowing the rest to reach the skin. These tend to be less viscous and easier to apply. Choose a sunscreen or sunblock formulated specifically for horses or a product made for people with sensitive skin. As with any product, read the label and follow application instructions.
Keep horses stabled during peak daylight hours. Keeping a horse entirely out of the sun is impractical and undesirable. But you do need to ensure that he has access to shade, whether from a run-in shed or a stand of trees. If your horse is prone to sunburn, you may want to take the extra step of keeping him in the barn during the day and turning him out after sundown.
If your horse does get sunburned, treat it as you would your own: Keep the area clean and protected from further sun exposure. If the skin develops blisters, scabs, bumps or other anomalies, something other than sunburn may be at work. One possibility is photosensitivity, a complex chemical reaction to sunlight that may indicate liver disease; another is squamous cell carcinoma, sun-related cancerous growths usually seen on or near the eyelids. If anything about your horse's sunburn looks unusual, call your veterinarian.