(5/2019) It's summer time and as the UV index rises it's important to remember that humans aren't the only ones that get sunburn. Cats, dogs, horses, and cows all get sunburn and can even get skin cancer. Even the type and location of skin cancer is fairly predictable based on where the animal is most likely to get sunburned. Animals are most likely to get sunburn and subsequent skin cancer on the lighter and pinker parts of their bodies. While not all skin cancer is caused by exposure to the sun, sun damage can be a contributing factor. Just like people it is important to protect the sensitive areas from the sun.

Cats tend to get burns and squamous cell carcinoma on their ears and nose. Dogs are more likely to get burned on their nose and ears where there is less hair. Pink skinned dogs with thin hair coats get sunburned more often than dogs with thicker coats. Dogs are more likely to get melanomas and mast cell tumors on their skin than other species.

While squamous cell carcinoma and melanoma are linked to sun exposure, mast cell tumors don't have a definitive known cause but genetics and skin inflammation may be contributing factors. These can be fatal if not treated so you should have your vet look at any suspicious lump. For dogs and cats the best way to prevent sunburn is to bring them inside during the sunniest parts of the day.

Horses and cows can also get sun burned and squamous cell carcinoma is the most common skin cancer for both of these species. They usually get squamous cell carcinoma around the eye and on their third eyelid. However, this skin cancer can occur on other body parts as well. It is also most frequently seen in lighter colored skin. Unlike with small animals, you can't just bring your cow or horse into the house during the midday hours. You can keep them in their stalls during the day or at least make sure they have access to a run-in-shed.

If your horses are like my horses, they will happily stand in their barn, but they like to poke their noses out the door and get sunburned noses. My horses have fly masks which help shade their eyes, however they don't like the type of masks with long noses. When I tried using that style, I would come home from work and have to walk the field looking for where my horses had left their masks. Eventually I gave up and opted for the masks without the long nose. Different fly masks offer a varying degree of UV protection. The masks are usually rated and should indicate how well they block light. Some of the more protective masks must be removed at night or the horse will not be able to see.

It is very important to check under the mask at least twice per day to make sure that the horses or cows haven’t injured themselves. While the mask does not make them more prone to injury, it does hide the injury and make the owner less likely to see the injury. This can lead to an eye injury not getting noticed for several days. An unnoticed, untreated, eye injury may lead to loss of the eye. Eye injuries are one of those types of injury that really need immediate care.

In order to protect my horses' noses from sunburn, I have tried a variety of different sunblocks. While you can use the human sunblock, I found that the regular sunscreen just didn't last long enough to provide adequate protection. Companies make lovely horse sunblock such as "My Pony Sunscreen" but they cost more than I want to spend. Even human zinc oxide sunblock can be pricey. I have found the cheapest and most effective sunscreen for my horses is either buying zinc oxide powder from Amazon and mixing it with water to form a paste to smear on their nose or using diaper rash ointment. Both of those options are relatively inexpensive and last all day.

Equine melanoma is more of a challenge to prevent. Keeping your horse inside during the day definitely helps. Unfortunately I have seen melanoma in even the most meticulously managed grey horses. Luckily equine melanoma is not as aggressive of a tumor as it is in people. Melanomas can be surgically removed, medically managed, observed, or treated with a melanoma vaccine. Frequently the melanomas are so slow growing that the owner chooses to just monitor the tumor. Unfortunately melanomas also form on horses where you can't see them. They can form internally and cause colic in horses.

One of the worst cases of sunburn I've seen was in an appaloosa mare. Princess Spotty-Bottom was an older horse so the owners had kept a heavy blanket on her all winter long. Unfortunately they did not take the blanket off of Spotty very frequently so when they did take it off in the spring, they discovered that she had developed a skin infection. The skin infection wasn't bad but I did warn the owners that her hair would likely fall out. I instructed them on how to treat the skin with medicated shampoo.

While the infection resolved fairly rapidly, the new hair growth was slow to come in. As the weatherman had predicted a beautiful sunny day, Spotty's owners turned her out in a grassy field. Everywhere that she had pink appaloosa spots, her skin burned. Her sunburn was bad enough that the skin peeled and she was very tender whenever anyone tried to touch her skin to apply medications. Several years later Spotty developed squamous cell carcinoma on her third eyelid. While I can't say that this was caused by the sunburn, the sun was likely a contributing factor. Luckily the owners were observant and I was able to surgically remove it before it got too large. The owners are very careful about sun exposure now. Spotty has a UV protective fly mask and she has sunscreen applied to all her pink spots whenever she goes out. She also has her turnout restricted and she is brought inside during the brightest parts of the day.

Sun protection is important for animals as well as people. While avoiding the sun is the best way to prevent sunburn and some skin cancers, sunscreen and appropriate protective wear can help too.