steps to limit the number of parasite eggs on the property, such as removing
manure, managing the pasture so it doesn’t get overgrazed, not dragging manure
to spread it over areas where horses are actively grazing, et cetera. Following
these simple measures can greatly reduce the odds of your horse picking up parasites and continuing the cycle.
FECAL EGG TESTING IS THE ONLY THING I CAN DO
TO PROTECT MY HORSE FROM PARASITES.
“The local environment determines whether transmission is likely
to occur,” says Cheramie. “Small strongyles are transmitted almost
exclusively on pastures.”
Eggs pass in the manure and develop into larvae, which crawl onto grass blades
to be ingested by horses; this is how the cycle continues. Horses in the wild
avoid grazing near manure, but this isn’t always possible in small or overcrowded
pastures. Horses kept in stalls and dry lots full-time have lower risk of becoming
As with so many things in life and nature, the 80/20 rule applies to parasites as well.
“Usually in a herd, 80 percent of the parasite burden is hosted by 20 percent
of the horses,” says Morgan. “High shedders are responsible for the majority of
Because these horses pass more eggs in their manure, they are the ones con-
taminating the pasture. Keeping high shedders out of the field can significantly
cut down on the number of infective larvae present.
Now that you are better armed to separate deworming fact from fiction, you
can keep you horse healthier and do your part to prevent resistance to deworming chemicals in parasites.
For more, check out the Internal Parasite Control Guidelines document from the
American Association of Equine Practitioners online at www.aaep.org.
CYNTHIA McFARLAND is an Ocala, Florida-based freelance writer, horse owner and avid trail
rider. The author of nine books, her latest is The Horseman’s Guide to Tack and Equipment.
For example, the rules for deworming foals are quite different than those
for mature adult horses. Foals are
susceptible to ascarids, and need to be
dewormed at least four times during
their first year.
It’s very important to develop a
plan with your veterinarian because
they know your farm management
practices, your individual horses and
their risk level. Once you have a
targeted fecal testing and deworming plan in place as advised by your
veterinarian, you can feel confident
that you’re controlling parasites and
reducing the risk of parasite-related
colic and weight loss.
MY HORSE NEVER LEAVES
THE FARM, SO I REALLY
DON’T NEED TO WORRY
Keep in mind that a horse can re-
infect himself with his own intestinal
“Even if you have just one horse
that never goes off site, he could still
have quite a parasite load just from
the eggs he himself passes and re-in-
gests,” says Gray.
It’s always a smart idea to take