Equine Sunbleaching vs. Dark Summer Coats

It’s the UV rays, of course, but a supplement may help.

Sun bleach isn’t inevitable. While genetics do play a role – and we can’t do anything about that – there are measures to help your horse’s coat stay glossy and true to its color. 

First, it’s important to understand just a little about the horse’s hair. Under a microscope, a hair in cross-section has three distinct layers. The outer layer is the cuticle, which is composed of overlapping cells, called scales, arranged like shingles on a roof. On its surface is a layer of fatty acids, which repels water and tightly seals the shaft.

The next layer is the cortex, which contains the pigment of the hair. At its center is a hollow area called the medulla, which used to house the blood vessels feeding the hair root.

There are two pigments in hair, eumelanin and pheomelanin. Eumelanin predominates in chestnuts and other light-colored coats, while bays, browns and blacks have high levels of pheomelanin. The purpose of the melanin pigments is to protect the hair from protein damage caused by ultraviolet radiation from the sun.

Exposure to ultraviolet radiation from the sun will break down the structure of melanin, or destroy it completely. his changes the way light reflects off the hair, causing the color change. And there are many ways to limit your horse’s exposure to UV rays.


Of course, the tried-and-true method is turnout at night. The downside, of course, is mosquito exposure, and that’s something to take very seriously. If you’re going to turnout at night, we recommend the use of Mosquito Halt fly spray.

Spring’s green grass is a natural remedy to coat problems, earning its nickname “Dr. Green.” Horses on good pasture get shiny, glossy coats quickly at this time of year. The downside is weight control, of course.

Be sure to keep your horse’s coat clean. Sweat is a huge factor in sun bleaching. If you don’t bathe your horse after each sweaty ride, you should at least rinse the sweat off of his body. A few ounces of liniment in the water bucket will help break through the sweat, but don’t over-do it as liniment can be drying to the coat, too.

· Avoid harsh, alkaline shampoos, like dishwashing detergents. Yes, they’re inexpensive and cut through greasy dirt well, but they’re too harsh for your horse’s coat. Equine shampoos aren’t that much more expensive. Good choices include:

· Corona Concentrate Shampoo

· Lucky Braids

· Absorbine ShowSheen Shampoo

UV Protection

There are products that help with UV protection, too, but be sure to read labels and realize that sweat, rain and dirt all wear away the protection.

The simplest choice is to choose a fly spray with UV protection. Among the best choices are:

· Aloe Herbal Fly Repellent Concentrate

· TRI-Tec 14 Fly Repellent

· UltraShield EX.

If you don’t use fly spray, you may consider a sunscreen for horses, such as:

· Healthy HairCare Sunflower Sun Scree

Human sunscreen products can be used, too, but be careful. We’ve had good luck with:

· Banana Boat SPF 30

Zinc oxide ointment/cream can be used, too, but we doubt you’d want to cover your horse in it!

While we have a fly sheets field trial in its final stages, these fly sheets list fairly high UV protection percentages on their labels. These sheets are good choices for UV protection:

· Weatherbeeta Kool Coat

· SmartPak

· HorseWare Mio

· Kensington Platinum

· Schneider’s Saddlery InterLock Mesh

· Kensington Platinum

· English Riding Supply Ovation Athletic.

Nutrition: Protection From The Inside Out

Two of the most common equine dietary mineral deficiencies are zinc and copper, and both impact heavily on melanin production.

Copper is essential for the enzymes that produce eumelanin, and both copper and zinc are needed to manufacture pheomelanin. The presence of the deficiencies is made even worse by commonly encountered high levels of manganese and iron, which compete in the horse’s body with copper and zinc for absorption and then worsens the deficiency.

Signs of deficiency of copper and zinc include:

· Red/rusty ends on black manes and tails.

· A brownish discoloration around the eyes on bays, brown, blacks.

· Loss of dapples.

· New coat in the spring or winter appears darker, more vibrant.

Problems with hoof quality and a predisposition toward developing thrush may also be noted. If you notice these things, your horse will likely sun bleach, and you may want to take a serious look at his diet.

The ideal way to correct a deficiency is to have your hay or pasture analyzed, then work with a nutritionist to design a program that meets all mineral minimums and also keep the iron:copper:zinc:manganese ratio 4:1:3:3. This means four times more iron than copper, three times more zinc and manganese than copper, zinc and manganese equal.

But this isn’t always practical, so you can add copper and zinc may be added individually, or as part of a multi-ingredient supplement. They are included in good hoof/coat products, including:

If you’re feeding no mineral supplements or supplemented grains, start with 200 mg of copper and 750 mg of zinc. If you use a supplement or supplemented grain but untested hay, try half these amounts, 100 mg of copper and 375 mg zinc as your starting point. If you don’t see changes within two weeks or so, start increasing the amounts by 50 mg of copper and 200 mg of zinc.

Like hoof wall, hair is predominantly protein (keratin) so exposure to UV radiation from the sun can also cause changes in the structural protein of hair, and drying. This can expose the pigment directly to light and air, speeding up its destruction. To help protect the hair, make sure horses not on good pasture are supplemented with flaxseed at a rate of 6 oz./day, for essential fatty acids.

While all commercial coat supplements have claims of better color, they’re not necessarily geared to prevent fading. The major ingredient in all of them is a source of fat, often from high-fat seed meals like soy or flax. This will definitely help sheen, especially for horses that are not getting pasture. Remember, too, that your hoof supplement is likely providing most of the same nutrients as a good coat supplement. There’s probably no reason to buy both.

Key amino acids (L-lysine, D,L- methionine) and B vitamins helps protect from shortfalls that influence protein metabolism. Vitamins A and D are critical for skin health, but not likely to be deficient except with very old hays. Many commercial products have added copper or zinc, but few specify the amount, and since a horse’s needs vary depending on what is already in the diet, a one-size-fits-all-fix is unlikely.

We did a summer field trial of commercial coat supplements for protecting color, but we didn’t find a magic bullet. All the trial horses showed a higher shine, but actual color change was judged to be minimal, compared to horses not on the trial but in the same barn with similar management.

Bottom Line

The best way to ensure an enviable summer coat is to combine efforts inside and outside the horse:

Follow our management tips, above, to help minimize UV exposure.

Take a good look at your horse’s diet and consider what nutritional supplements might best fit his individual needs.

Other than money, there’s no strong reason not to try the coat-darkening supplements, as they did create glossier coats. We saw minimal changes in actual coat color, however, but if you’re going to try one, the sooner you begin, the better your odds. It takes time for a horse’s coat to show the benefits. We feel choices with a flaxseed base give you the benefit of the fatty-acid protection as well, such as the products from Horse Tech.

Remember that many hoof supplements make excellent all-around supplements, and that includes a healthy coat. This is not surprising, since the horse’s coat and hooves both require the same key nutrients. We are working on a hoof supplement update article, so stay tuned.

If you’re truly on a budget, the easiest and least expensive method is to pay specific attention to copper and zinc. You can find these individual ingredients at Uckele Animal Health and Horse-Tech.

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