The ear is a complex and delicate part of the horse's anatomy, writes Dr. Michael A. Ball of Cornell University in the May edition of The Horse. His in-depth article explores a variety of topics related to the ear, including the following:
The ear as a twitch. It is not uncommon to grab (with your hand) the ear of a badly behaving horse in an effort to get him to stand still. The ear can be an extremely effective "restraint" mechanism- but be careful. Some horses respond violently to the grabbing of an ear and might become worse or smack you in the head. Placing a twitch on the ear is not a good idea. There are a great number of nerves in the base of the ear, and there is a risk of damage that could result in permanent droopiness or floppiness. Also, if the cartilage is damaged, the ear can become permanently disfigured. It is best to reserve twitches for the muzzle.
Fly bite prevention. If possible, leave the hair on the inside of a horse's ear as long as possible. In addition, the application of petroleum jelly on the inner surface of the ear can act as a barrier affording some protection. Of course, there are many fly sprays on the market. However, a word of warning regarding such products--some horses are more sensitive to them than others. Be careful not to apply a concentrated fly repellent to the inner surface of the ear. Read the label carefully and make the full dilution recommended before using any product. Apply any new repellent sparingly and observe carefully for any sensitivity.
Fly bite dermatitis. If your horse has a hypersensitivity to fly bites--if the inside of the ear is peppered with welts during the peak of fly season- the chances are good that fly bites are related to the dermatitis. The area should be gently cleaned to remove crusted blood and other debris. Over-the-counter hydrocortisone creams can be helpful in quieting down the inflammation. Another product that can be helpful in reducing this type of inflammation is Preparation H or one of the other generic hemorrhoid creams containing shark oil. The best way to deal with these horses is to reduce their exposure to flies by keeping them inside during the day and turning them out at night.
The neonatal ear. The ear can be very useful in the evaluation of a newborn foal. If the ear is extremely floppy and has poor development of the cartilage at its base, prematurity or dysmaturity might be a factor. If the foal seems sick or depressed, the presence of small hemorrhages surrounding the blood vessels on the inner surface of the ear (the pinna) might be an indication of neonatal septicemia.
The ear tooth. The technical name for an ear tooth is "dentigerous cyst." Also known as an "ear fistula" or "conchal sinus," the ear tooth can be a cause of discharge from the base of the ear. The cyst actually is considered to be a type of tumor that has its origins in a small congenital defect involving the abnormal retention of a developmental structure that forms dental material. Such cysts are relatively rare and usually are noticed during the period of active tooth development (within the first two years of life). Surgical removal of the cystic lining and its contents is the only viable treatment.
Peripheral vestibular disease. The condition can be caused by head trauma and diseases or infections affecting the inner-middle ear. A loss of balance often is observed, and other symptoms include bleeding from the ear canal and tilting of the head.