A long, flowing mane and tail come naturally for a horse, so if you notice that the hair on your horse's mane and tail is suddenly becoming sparse, it is important to get to the bottom of things. There are a number of things that can cause hair loss in horses, including nutritional deficiencies, parasitic infections and fights with other horses.
Know What is Normal
Some breeds of horses, most notably Appaloosas, often do not develop the long flowing manes and lush tails seen in other breeds. For many Appaloosas, hair loss in the tail is common, and sometimes the mane is affected as well. Even so, if your Appaloosa suddenly goes from a full mane and tail to a sparse one it is a good idea to call the vet.
If your horse's tail is becoming sparse and straggly it could be from a parasite infection. Check the top of your horse's tail for signs of rubbing. If you see lots of broken hair strands near the top of the tail there is a good chance your horse needs to be dewormed.
Fights With Other Horses
Horses are herd animals, and as such they will develop a pecking order. But even after that pecking order is established, other horses may challenge the dominant horse in the herd. Most of the time these challenges will be small scuffles, but they can result in the dominant horse taking a chunk of hair out of the mane or tail of a rival. Watch your horses in the pasture and keep an eye out for signs of trouble.
If your horse's mane and tail are getting thin, be sure to watch for other signs of a potential nutritional imbalance or deficiency. If your horse has a nutritional deficiency you may also notice a dull hair coat and a listless attitude. If you suspect a nutritional problem, be sure to call your vet right away.
Horses do sometimes lose hair as they age, so if your horse is a senior citizen you may see some hair loss in the mane and tail. But even though this hair loss can be normal, it is still important to monitor your horse's health and contact your vet if something appears to be wrong.