Question

I own a 1200-lb (550-kg) Percheron/Appaloosa mare that is worked lightly once or twice weekly. She is turned out at all times on bahia grass pasture and is fed 1.5 lb (0.7 kg) each of a sweet feed and a balancer pellet. The mare is normally black, but she is getting white hair around her eyes and on her muzzle. In the summer, her coat gets reddish-black. I read that coat color changes could be a sign of copper deficiency. Her coat has become shinier since I started giving her a cup or two of black sunflower seed every other day, but I'm concerned about the hair color change. Your thoughts?

Answer

Because your mare is part Appaloosa, I can’t help but feel like the appearance of the white hairs may have something to do with her breeding. The fading coat is another common phenomenon among horses that live outside, especially in sunny climates like Florida.

There can be a correlation between low copper or zinc in the diet and bleaching of the coat. However, on review of the mare’s diet, it does not look like she is suffering from a shortage of either.

Let me go through how I came up with how much of each mineral she is consuming in her diet. The balancer pellets has 200 mg/kg copper and 400 mg/kg zinc; the sweet feed has at least 50 mg/kg copper and 200 mg/kg zinc, and the bahia grass has an average of 6 mg/kg copper and 24 mg/kg zinc.

The Kentucky Equine Research (KER) recommended daily allowance for a 1200-lb (550-kg) horse in light work is 143 mg copper and 429 mg zinc. Feeding 1.5 lb of balancer pellet, 1.5 lb of sweet feed, and 22 lb of bahia grass reveals your mare is consuming on a daily basis approximately 227 mg copper and 540 mg zinc, both exceeding the recommended daily allowance.