Remember from childhood how we thought it was cool the way sun bleached our hair over the summer'? But it's not so cool when it happens to your horse's coat. THere's hope, though, as this bleaching isn?t inevitable. The coat can be sun-proofed from the inside out.
The structure of hair shafts is similar in ways to a tree. Under a microscope, a hair in cross-section has three distinct layers. There is an outer layer called the cuticle. It is composed of overlapping cells, called scales, arranged like shingles on a roof. In three dimensions, these cells resemble cups stacked one inside the other.? On the surface of the cuticle is a layer of fatty acids, strongly bound to the amino acid cysteine. This layer repels water and tightly seals the shaft.
The next layer in is called the cortex. It is composed of elongated cells packed into bundles of fibers. This layer contains the pigment of the hair. At the 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. This changes the way light reflects off the hair, causing the color change.
NUTRITION TO THE RESCUE. Two of the most common equine dietary mineral deficiencies are zinc and copper, which 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.
If you feed your horse a balancer-type product, or a balanced commercial grain, you are providing anywhere from less than half to the full minimum mineral requirements. However, the horse will also take in minerals from hay or pasture, so the overall diet may not be well balanced. This can result in coats that are prone to bleaching.
The ideal way to stop this 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.
If a hay analysis is not practical, you can use the guidelines in the next paragraph as a starting point. The copper and zinc may be added individually, or as part of a multi-ingredient supplement. However, if you're going with a multi-ingredient supplement, in most areas, you'll want to avoid or greatly minimize any added iron and manganese.
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 combat this, make sure horses not on good pasture are supplemented with flax, 6 oz./day, for essential fatty acids or use Kentucky Karron Oil.
Also, rinse dried sweat from the coat with plain water on a regular basis and avoid shampoos that are alkaline.? Good shampoo choices include: Corona Concentrate Shampoo (www.coronaconcentrate.com, 800-241-6996), Lucky Braids (www.luckybraids.com, 781-665-5988) and Absorbine SuperPoo (www.absorbine.com, 800-628-9653).
COMMERCIAL SUPPLEMENTS.While all coat supplements have claims of better color, they're not necessarily geared to preventing 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. A typical daily hay intake of around 10 kg (22 pounds) falls around 200 grams short on fat compared to fresh pasture grasses. Maintaining the watertight seal on hair shafts helps protect from the drying effect of the sun.
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.
Some commercial products have added copper or zinc, but few specifiy 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 weren?t impressed (see sidebar).? In fact, with one exception, the changes were? insignificant. The one that changed the most had a full dietary analysis and was then supplemented with copper and zinc only. See PDF:?more sun-bleached recommended products and additional information.
BOTTOM LINE. Many hoof supplements (see May 2009, www.horse-journal.com) make excellent all-around supplements, including for coats. A couple of them are listed in our zinc/copper sources sidebar. This is not surprising, since the horse's coat and hooves both require the same key nutrients. And that makes a hoof supplement a good choice for many horses.
However, the easiest and least expensive method is to pay specific attention to copper and zinc. You can add generic poly copper and poly zinc to your horse's feed at the levels we recommended earlier in this article.