Quest Gel, Quest deworming gel, Quest Gel Wormer for horses, Queensville Farm Supply Queensville Ontario.

Virtually every horse is infected by internal parasites. If left unchecked, these tiny invaders can cause poor performance, weight loss, or even death. Every horse owner should know the symptoms of internal parasite infection, and how horses become infected. There are several important species you should be familiar with. Fortunately, there are many things you can do to protect your horse from parasites, including regular deworming.


Does my horse have worms?
Symptoms of internal parasite infection include:

• Diarrhea
• Weight loss or poor growth
• Episodes of colic
• Coughing
• Loss of appetite
• A “pot belly”
• Rough hair coat
• Tail rubbing (“rat tail”)

If you see these symptoms, contact your veterinarian right away. Your equine veterinarian is the most qualified person to diagnose and treat a possible parasite problem. Recommended treatment may include the use of an equine dewormer like QUEST Gel.

How are horses infected?
The internal parasite life cycle starts in the pasture, where parasite eggs are shed in the horse’s feces. Infective larvae migrate out of the feces and onto nearby grass, where they are swallowed by the grazing horse. The larvae then grow through several stages. Depending on the species, they may travel throughout the body, damaging the stomach, intestines, blood vessels, liver and lungs. Once parasites reach adulthood, they begin producing eggs which are deposited back into the pasture – starting the worm cycle all over again. Botflies deposit their eggs directly on the horse’s body; the eggs are ingested when the horse licks itself.

Which worms should I worry about?


Small strongyles: Public Parasite Enemy #1.
Small strongyles (Cyathostomum, Cylicocyclus and Cylicostephanus spp.; Gyalocephalus capitatus) are the most common and economically devastating parasites of adult horses. Small strongyles are dangerous because of their unique ability to “encyst” inside the horse’s intestinal wall for up to months or even years at a time. When large numbers of encysted small strongyles emerge from the intestinal wall all at once, they release dangerous toxins into the horse’s system. This release can cause a variety of intestinal problems, including:

• diarrhea
• anemia
• severe and rapid weight loss
• colic
• fever
• death

QUEST is the only dewormer that kills dangerous encysted small strongyles in a single dose, before they emerge and release metabolic wastes into the horse’s system. This further reduces the number of eggs shed by the horse, and helps keep pastures clean significantly longer than other equine dewormers.


QUEST controls these other common parasites as well:

Bots (Gasterophilus spp.) migrate through the mouth and into the stomach where they may cause ulcers or abscesses. Fall is the best time to treat for bots, when the larvae are in the stomach and can be killed all at once.

Large strongyles or Bloodworms (Strongylus and Triodontophorum spp.) disrupt blood flow and can destroy arteries and blood vessels. They can cause anemia and brain damage.

Roundworms or Ascarids (Parascaris equorum) mainly affect young foals. They can cause pneumonia, chronic diarrhea and poor growth.

Pinworms (Oxyruis equi) irritate the horse’s tail, causing tail rubbing and weight loss.

Hairworms (Trichostrongylus axei) can cause watery diarrhea. They live in the horse’s stomach and small intestine.

Stomach Worms (Habronema muscae) live in the horse’s stomach lining, causing gastric abscesses or ulcerations.


How can I protect my horse?
Certain management practices can dramatically reduce the number of internal parasite eggs and larvae in your pasture.

• Remove feces from the pasture at regular intervals. Twice a week is recommended.
• Avoid feeding horses on the ground. Provide a feed rack.
• Group pastured horses by age, to avoid exposing youngsters to heavy larval populations.
• Don’t overstock pasture, which forces horses to graze near feces. If possible, provide at least one acre per horse.
• Isolate and deworm new horses that are arriving on the farm.
• Rotate sheep or cattle in horses pastures, as these species are not infected by small strongyles. Grazing these species helps reduce pasture contamination by removing the L3 larvae, thus breaking the cycle of infection.
• Work with your veterinarian to develop a year ‘round parasite control program that includes the use of an effective equine dewormer like QUEST Gel.

How often should I deworm?
That depends on your dewormer. Some need to be used daily, others every six weeks or more often. Because QUEST has the longest strongyle egg suppression claim of any dewormer –- 84 days – you only need to use it once every 3 months in adult horses. QUEST has been shown to suppress strongyle egg production up to twice as long as ivermectin (Zimecterin®, Equimectrin™).


Deworming schedules can vary by region or climate. Always consult your veterinarian before starting or changing a parasite control program.


* Les Sellnow “Parasites and Pastures” The Horse August 1999.

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