Tapeworm Dewormer in Horses

Many horses pastured with a herd or kept in an active stable will be exposed to common parasites such as worms. While research has traditionally been geared to the more dangerous types of worms, tapeworms are a problem that can affect horses in all regions. Because diagnosing a horse with tapeworms is difficult, preventative treatments with commercial deworming medications are suggested.

  1. Tapeworms

    • Tapeworms are a common problem that often goes unnoticed in horses due to the lack of external symptoms. The life cycle of a tapeworm involves two hosts. An infected horse passes the tapeworm eggs with its stool. The eggs are eaten by oribated mites, which live in pasture grasses. The tapeworm eggs hatch into larvae in the bodies of the oribated mites, and the mites are ingested by grazing horses. Once in the intestines of the horse, the larvae develop into adult tapeworms.

    Dewormers

    • Traditional deworming medications for horses were moxidectin, ivermectin, oxibendazole or fenbendazole based products. However, none of these medications were effective in the prevention or treatment of tapeworm infestations.

      In 2005 the FDA approved medications that were commonly used for dogs and cats for use on horses. Praziquantel and pyrantel pamoate based medications were found to be effective against tapeworms, and are now available for over the counter use.

    Administering Dewormers

    • Dewormers are most commonly found in a paste form that is packaged in a large tube-like syringe. The dosage is based on the weight of the individual horse. Weighing a horse can be done easily with a weight tape that measures the radius of the horses body at the heart girth. To measure the heart girth measure the area located just behind the front legs and over the high point on the horses back.

      The horse's mouth should be rinsed out with a few syringes of water to dislodge any feed or grass that may be in its mouth. The dial on the dewormer should be turned to match the number to the weight of the horse. Dewormer is applied directly into the mouth, behind the molar teeth. It is helpful to hold the horse's head up to prevent it from spitting out the paste.

    Deworming Schedule

    • A veterinarian can help horse owners develop a dewormer rotation schedule that will include Praziquantel and pyrantel pamoate. All horses that are turned out together should be wormed at the same time to prevent reinfection amongst the herd.

      A deworming rotation schedule usually will consist of alternating between an ivermectin based dewormer, Praziquantel and pyrantel pamoate. Each wormer is given at a set time of the year, with eight weeks between each dose.

    Prevention

    • Preventing all types of worms before they become a problem should be the goal of all horse owners. Along with regular use of deworming medications, avoiding over crowding pastures is the best way to prevent tapeworm infestations. Horses will typically avoid grazing in areas where manure is present. When pasture overcrowding occurs it leaves horses no option to seek grass free from manure.