Resistance to dewormers is increasing in these worms, so targeted deworming is especially important.

Cyathostomins cause severe gastrointestinal signs such as decreased appetite and diarrhea.

Live in the large intestine and migrate into the wall of the intestine.

Bloodworms used to be a major problem in horses, but their occurrence and significance has decreased with appropriate deworming.

Can migrate through the arteries around the large intestines and cause colic.

Older affected horses may have a poor hair coat, weight loss or decreased performance.

Young animals with very heavy burdens can have obstructed intestines - leading to colic and possibly death.

In young horses, roundworms cause poor growth and development as well as respiratory signs.

Migrate through the trachea and live in the small intestine.

Most common in horses less than one year old and in very old animals due to decreased immunity.

Foals should be dewormed with an ivermectintype product around 12 months of age and then every three to four months with a product chosen based on their fecal egg counts.Ĭommon worms Roundworms (Parascaris equorum).

In the prairie provinces, foals do not need to be dewormed through the winter when temperatures are below freezing. They should first be dewormed around two months of age with fenbendazole, and then retreated with this product every two months until they are yearlings.

Foals need much more frequent deworming than other horses.

Mothers should be dewormed with an ivermectin product 24 hours after foaling.

Pregnant mares should be dewormed in the spring before they foal with a dewormer chosen based on the results of a fecal egg count.A fecal egg count is included in the spring herd health packages offered at many local boarding facilities. We strongly recommend conducting a second fecal egg count in the fall, but many owners elect not to do this second procedure.Your local veterinarian can advise you about what deworming product to use in the fall based on the common parasites in your area.

We recommend that horses be dewormed in the late fall, after a hard frost, with an appropriate deworming product.Based on the results, we will recommend whether you need to deworm your horse. This procedure allows us to measure the number of worm eggs a horse is shedding in its feces. Before deworming in the spring, we recommend having a fecal egg count (FEC) done. Most horses only need to be dewormed once or twice a year.

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