Internal parasites are a normal part of a horse's life on pasture, but left unchecked, heavy parasite loads can cause weight loss, poor coat condition, and even colic. Knowing the major players helps you and your vet manage the risk.
Roundworms & Strongyles
Large and small strongyles ("bloodworms") are among the most significant parasites in adult horses, while roundworms (ascarids) are a particular concern in foals and young horses.
Tapeworms & Bots
Tapeworms are linked to certain types of colic and require a specific class of dewormer to treat effectively. Bot fly larvae, visible as small yellow eggs on the legs in summer and fall, are addressed with an ivermectin-based dewormer.
Bot fly eggs can be scraped off with a bot knife or fine-toothed comb before they hatch and are ingested when a horse grooms itself.
Detection
A fecal egg count test, run by your vet, is the best way to know exactly which parasites (and how many) your horse is carrying, guiding a more targeted and effective deworming plan.
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