Dangers of Horse Wormers

Horses pick up parasites easily through grazing. This is especially true if the horse is confined to a small pasture or if stable areas are not kept sufficiently clean. Some horse wormers can be administered by non-professionals, but others require a veterinarian's prescription and oversight. The correct dosage is crucial to ensure the health of the horse, as well as the parasite's elimination. Horses with certain medical conditions should not be given certain formulas, but overall the dangers of horse wormers are minimal.

  1. Types

    • The active ingredients in different horse wormer brands target different parasites. Fenbedozole-based wormers treat horses for roundworms, pinworms, redworms and certain types of stomach worms. Oxibendazole-based wormers treat threadworms and large strongyles. Ivermectin-based wormers treat for all these types plus lungworm and bots.

      According to alphahorse.com, most worming medications are safe for healthy, adult horses. Even high overdoses are rarely harmful. Foals and horses with weakened immune systems, on the other hand, should be given horse wormers with caution.

    Worming

    • Almost all horses have some level of worm infestation, according to acreageequines.com. There are often few, if any, symptoms so a regular worming schedule is usually a good idea. Twice yearly is usually a safe and effective worming schedule. Worming frequency may depend on regional parasite prevalence and the cleanliness of stables and pastures.

      Young horses, especially foals and yearlings, may show symptoms such as dull coats, weight loss, listlessness and coughing. Colic, sores, hair loss and intestinal disorders may also occur, especially when the parasite load is high.

    Dosage

    • Administering the proper dosage of horse wormer is emphasized by the drug manufacturer. Overdosing can harm the horse's health, while underdosing won't eradicate the parasites. According to drugs.com, the appropriate dose varies by the weight of the horse. Adult horses weighing about 900 lbs. typically receive a dose three times as large as foals weighing 300 lbs., but consult the specific medication instructions and your veterinarian.

    Considerations

    • Some horse wormers -- alfalfa pellet horse wormer, for example -- are not recommended for horses with kidney problems unless a veterinarian is closely overseeing the process. Very young or underweight horses may be easily overdosed if the person administering the medication is not careful. Moxidectin-based wormers have a very low overdose tolerance and should be doled out with great care.

    Prevention

    • A few preventive measures can help decrease the need for horse wormers. Many parasites are transferred from horse to horse by contact with feces. Cleaning stables twice a week and plowing grazing lands under on a regular basis lowers the risk of worm infestation. Keeping horses clean and curried can protect them from accidentally ingesting parasite eggs on their coats. Providing grain and hay in feeders off the ground decrease feed contamination.