You can tell when your own hair is dull and lifeless, lacking a healthy and glossy shine. A horse's coat is not that much different, and it is one of the best indicators of overall horse health. While many grooming products can add sheen to your horse's coat, the best way to achieve a healthy coat, or to resolve a poor horse coat, is from the inside-out: proper nutrition and care.
According to Janet M. Roark, a veterinarian in Austin, Texas, poor nutrition can cause a dull coat as well as dry and flaky skin. Most of a horse's nutritional requirements can be found in good forage, such as hay and pasture grass, so test yours to confirm adequate nutrients. Essential fatty acids, protein and vitamins are all essential, as are trace minerals such as zinc and copper. Supplement with a prepared grain, salt block or individual ingredients such as flaxseed if your current feeding regimen is lacking any of these vital ingredients.
"Internal parasites are a common cause of poor-quality coats in horses," Roark says. "Keep your horse on the recommended deworming schedule designed for parasites in your region." If you are unsure of the proper deworming schedule or have concerns about excessive deworming, take a fecal sample to your veterinarian for analysis. She can prescribe a custom deworming program for your horse.
Your horse may have a skin condition that is affecting his coat quality. Rain rot, ringworm or other types of fungal conditions are not uncommon in horses. Sweet itch or other allergic reactions can also be factors. Inspect your horse frequently as you are grooming for abnormal matting, patchiness, clumpy shedding, spots, bumps or other inexplicable marks. Also inspect his pasture mates because some conditions, such as ringworm, are very contagious and can spread from one horse to another.
Roark also notes that your horse's poor coat quality could be an indicator of an underlying disease or illness, such as Cushing's disease or gastric ulcers. Cushing's disease can affect any horse but is more common in older horses, and is the result of high levels of the steroid hormone cortisol. You may notice that your horse is not shedding his winter coat, and the hair is wavy and coarse. In addition to poor coat quality, suspect gastric ulcers if your horse frequently colics or exhibits symptoms similar to colic, including loss of appetite and attitude changes.