Quality, compassionate care for horses.
Deworming Adult Horses
Horses over the age of two have more mature immune and gastrointestinal systems than their younger counterparts. As such, they are able to more effectively manage GI parasites. More effective natural management means less frequent deworming.
Annual fecal floats are the recommended method to determine deworming protocols in adult horses. Fecal floats allow us to determine the most effective deworming schedule based on the number and type of parasites actually in the intestines. Fecal floats also allow us to monitor for parasite resistance to deworming products. For example, pyrantel has become nearly obsolete in managing GI parasites in adult horses due to resistance.
Our goals of using fecal floats are:
- reduced parasite resistance
- cost effective protocols for owners
- efficient protocols for horses
vetmed.illinois.edu
For most horses in northern Colorado, deworming 2-3 times per year is sufficient to maintain low levels of parasite egg shedding. We typically recommend a product to kill tapeworms and hibernating roundworms (Quest Plus) in the fall after a hard frost. The other 1-2 dewormings are dependent on the fecal float results.
As with vaccines, broodmares require a very specific deworming schedule. It is important to follow the protocol to ensure the safe development of the fetus and to reduce parasite egg shedding at the time of foaling. We typically recommend the following for broodmares:
- 4 months: Fenbendazole (Panacur, Safe-Guard)
- 5 months: Pyrantel (Strongid)
- 7 months: Ivermectin (Equell, Zimectrin)
- 10 months: Ivermectin (Equell, Zimectrin)
- 5 days after foaling: Pyrantel (Strongid)
Please note: Horses under the age of 18 months and ponies should NOT be given moxidectin (Quest). This product has a more narrow safety margin; overestimations in weight can be more detrimental with this product.
photo courtesy of: extension.usu.edu (T= tapeworm, Arrow= Strongyle/ Small Roundworm, R= Ascarid/ Large Roundworm
Deworming Foals and Weanlings
Because of their immature immune system, foals, weanlings, and yearlings have unique deworming needs. Starting at 2-3 months old, foals require more frequent deworming with a wider variety of products for the first 18 months of life to adequately prevent parasite infestations.
Ascarids are the GI parasite of greatest concern in young horses. High numbers of ascarids cause severe impactions and colic in foals and weanlings. Ascarid- associated colic occurs commonly in foals that have recently been dewormed but have little to no previous deworming history or in foals that have not been dewormed at all. When large numbers of ascarid worms are killed all at once, the intestines are "flooded" with dead worms and toxins from the die-off; this can create a large impaction. Because of this risk, frequent, appropriate deworming of foals is crucial.
Please contact us to discuss an effective deworming strategy for your foal or weanling. Prevention is key!
