Overview of Lice in Horses

Lice infestation in horses can be a trial some for both your horse and you. Your horse is plagued by incessant itching, and you must work hard to kill existing lice and prevent the offspring from reproducing and continuing an infestation cycle. Understanding the symptoms and causes, knowing how to diagnose the condition and taking preventive measures is the key to successfully removing lice infestations in horses.

  1. Types of Lice

    • According to PetMD, there are two main species of lice that can infest a horse: Haematopinus asini (H. asini), which feeds by sucking blood and Damalinia equi (D. equi), which feeds by biting the flesh, causing itchy irritations. Both types of lice are tiny, about 0.08 to 0.16 inches in length when fully grown, and both can be found anywhere in the world.

    Symptoms

    • Lice infestation often occurs in the winter months when the horse's hair is long and thick. According to PetMD, this parasite usually settles in the hair roots of the forelock and mane, near the base of the tail and on the hairs above the hooves. Symptoms include a dull coat, hair loss, matting hair and itchy skin. Severe cases of lice can result in a loss of muscle tone and anemia. A horse with itchy skin will rub its body on objects or bite at its skin, often leaving hairless, raw spots.

    Diagnosis

    • A thorough inspection of your horse will determine the presence of lice. Its hair must be parted to expose the skin. PetMD suggests examining the face, neck, ears and tail area. The biting species of lice, D. equi, can often be seen moving around throughout the hair. The sucking species, H. asini, is more sedentary, requiring closer examination. Inspections should also include the detection of louse eggs, which are attached to hairs near the skin surface. These eggs are whitish in color, somewhat translucent and elliptical in shape, according to PetMD.

    Causes

    • An article in the July 2007 issue of "Equus" magazine pointed out that horses with compromised health or living with a large number of other horses are most susceptible to lice. Because the life cycle of lice is very short--about ten days--you may not notice the problem until your horse is infested, according to PetMD.

    Solution

    • PetMD outlines several steps to treating a horse with lice infestation: First, the coat of your horse should be clipped. A thinner coat will discourage lice migration and breeding. Second, treating your horse, its brushes, tack and scratching posts with insecticidal medication or powder is necessary to kill the existing lice. This treatment should be applied at least every two weeks to stay ahead of the rapidly reproducing lice, suggests PetMD.

    Prevention

    • Grooming, exercise and a healthy diet help prevent lice.

      Not overcrowding pastures with a large number of horses will reduce the likelihood of lice. Maintaining a horse's health and conditioning is also important. This can be done by providing your horse with frequent grooming and exercise, as well as a healthy diet.