Why Deworming Is Important for Your Horse
Your horse may look perfectly healthy despite the host of parasites living inside its body. Without regular deworming, those parasites could soon cause issues ranging from weight loss to diarrhea and colic.
Common Horse Parasites
Your horse's body offers the perfect home for many types of parasites, including these invaders:
- Large and Small Strongyles. Large strongyles live in the large intestine and may cause weight loss, appetite loss, diarrhea, fever, and colic. Death can occur in severe cases. Small strongyles live in the lining of colon and cecum (a pouch that makes up the first part of the large intestine). Small strangyles can interfere with the digestion of nutrients and cause weight loss, diarrhea, and colic.
- Ascarids (Roundworms). Ascarids are most common in foals and can slow a young horse's growth rate. Other signs include pot belly, dull coat, or decreased appetite.
- Tapeworms. Have you noticed flat, white worms in your horse's feces? Your horse may have a tapeworm infestation. Tapeworms make themselves at home in the colon and the end of the small intestine. The worms reduce the amount of nutrients your horse receives from the food it eats, which can lead to diarrhea, colic, poor body condition, and slow growth.
- Stomach Bots. Your horse ingests botfly larvae after botflies lay eggs on its body. Bots cause sores in the stomach, mouth, and esophagus, making eating painful for your horse. Stomach ulcers, weight loss, diarrhea, and colic can also occur due to bots.
- Pinworms. If your horse constantly rubs its tail against its anus, it may have pinworms. Pinworms can cause itching and hair loss around the anus.
- Threadworm. Threadworms most often affect young foals and may damage the lining of the small intestine. The worms may cause diarrhea and slow growth.
Protecting Your Horse's Health with Deworming
Deworming medication kills parasites, preventing your horse from developing uncomfortable or serious health issues. Parasites intercept and absorb nutrients before your horse's body can digest them. As a result, your horse may lose weight even if its eating habits haven't changed. Nutrient deficiencies can also affect your horse's condition and coat. Large numbers of strongyles can lead to anemia, a condition that occurs when the blood doesn't contain enough healthy red blood cells.
Parasites may also increase your horse's risk for colic, one of the most common causes of death in horses, according to The Horse. Colic, the term used to describe abdominal pain in horses, occurs for many reasons, including inflammation of the gastrointestinal tract, parasitic infections, blockages, gas, or twisted intestines.
Parasites may also negatively affect your horse's overall health. Battling parasites stresses the immune system and makes it harder to fight off viruses and infections.
Fortunately, regular deworming can help your horse avoid serious health issues. Although deworming was once recommended as often as six times per year, less frequent deworming may be just as effective and can reduce the risk that the parasites will become resistant to the dewormer.
Parasites can spread from one horse to others in the herd. Deworming offers a simple way to keep all of your horses healthy.
Your horse will need a mix of dewormers to kill both larvae and mature parasites. For example, the University of Minnesota Extension recommends using ivermectin and moxidectin to treat larval strongyles and oxibendazole, fenbendazole, or pyrantel parmoate for adult worms.
The American Association of Equine Practitioners (AAEP) recommends testing fecal egg counts once or twice per year to classify horses as low, medium, or high shedders. Shedding is measured by the amount of eggs per gram (EGP) in manure. Low shedders have 0 - 200 EPG, moderate shedders have 200 - 500 EPG, and high shedders have more than 500 EPG. The AAEP suggests deworming all horses once or twice per year and deworming high shedders more often.
Has it been a while since your horse's fecal egg count was tested? We can check your horse's feces and help you create the best deworming schedule based on test results. Contact our office to schedule an appointment.
Sources:
The Horse: What You Should Know About Colic in Horses, 7/4/2023
https://thehorse.com/1114359/what-you-should-know-about-colic-in-horses/
American Association of Equine Practitioners: Internal Parasite Control Guidelines, 5/31/2024
https://aaep.org/resource/internal-parasite-control-guidelines/
University of Minnesota Extension: Deworming Your Horse, 2021
https://extension.umn.edu/horse-health/controlling-and-treating-parasites-your-horse
PetMD: Horse Dewormers: Uses, Types, and Schedule, 8/20/2024
https://www.petmd.com/horse/horse-dewormers
University of Georgia College of Agricultural & Environmental Science: Equine Parasite Control: Moving Beyond Rotational Deworming