Choosing a Horse Dewormer Pack

Read up on horse dewormer packs, recommended horse deworming schedule, and more

Did you know there are more than 150 species of internal parasites that can infect horses? Some of the most common include: large strongyles, small strongyles, roundworms, pinworms, hairworms, stomach worms, bots, encysted small strongyles and tapeworms. When left untreated, worms in horses cause critical damage to their vital organs, impair growth, hinder performance and even cause colic.

When to Deworm a Horse

First things first: Work with your veterinarian to perform a fecal egg count (FEC) test, which will help determine your horse’s level of parasite burden and guide you on the frequency of deworming treatments needed to keep them healthy.

American Association of Equine Practitioners (AAEP) parasite control guidelines recommend deworming adult horses when parasite levels can be at their highest, during the spring and fall. There are, however, situations requiring horses to be dewormed more than twice yearly, such as a horse being deemed a high-shedder (>500 eggs per gram), or if deworming a young horse or foal.

A number of elements can contribute to higher levels of parasite shedding, requiring more treatments, such as:

Boarding and training barns, which house greater numbers of horses that may contribute to increased parasite burden

Movement of horses on and off the farm for training or competitions, presenting greater contact with other horses

Foals, weanlings and geriatric horses, which are often higher shedders of eggs

High stocking densities (more than two horses per acre) and nonrotated pastures, which are proven to increase parasite levels

Deworming Adult Horses

Horses deemed low shedders (0 to 200 EPG) should be dewormed twice a year, with Ivermectin in the spring and Quest Plus late fall/early winter. Moderate shedders (200 to 500 EPG) should be dewormed three times a year, with the same schedule as above but with an additional late spring/early summer treatment with Ivermectin.

Deworming High-shedders and Young Horses

High shedders (>500 EPG), yearlings, and 2-year-olds should be dewormed four times a year. A convenient one year horse wormer pack is available from veterinarian-founded Valley Vet Supply. To best care for high-risk horses, consider the Annual Young Horse and High Shedder Dewormer Pack. The dewormer pack was developed by the Valley Vet Supply Technical Service Veterinarian team, with guidance from the AAEP Parasite Control Guidelines, and offers young horses and horses deemed high-shedders a comprehensive, convenient pack to help ensure horse health and reduced parasite burden.

With this convenient yearly horse wormer pack, you can control parasites in yearlings, 2 year-olds, and high shedders. The package contains four dewormers, directed to be used as follows:

March 1: Ivermectin
June 1: Quest
Sept.1: Ivermectin
Dec. 1: Quest Plus

Deworming Foals

Foals are even more susceptible to parasites than adult horses, making their protection against them all the more critical, and frequent. Ascarids, also known as roundworms, are their greatest concern, as ascarids quickly impact the young foal’s immune system, causing respiratory challenges, stunted growth, lethargy, and even colic.

Treat foals against parasites with this convenient Annual Foal Dewormer Pack. Developed by the Valley Vet Supply Technical Service Veterinarian team, with guidance from the AAEP Parasite Control Guidelines, the package contains six dewormers for use as follows:

2 months of age: Oxibendazole or Fenbendazole
4 months: Pyrantel
6 months: Oxibendazole or Fenbendazole
8 months: Ivermectin Plus
10 months: Quest Plus
12 months: Ivermectin

Additional Tips for Deworming Horses

Before deworming horses, use a weight tape or digital livestock scale to dose the horse wormer to their exact weight. Steps to using a weight tape: Make sure the horse is standing square; place weight tape around the horse’s heart girth; for the closest weight approximation, see the number where the tape meets; and set horse wormer paste to the correct weight to administer an accurate dose.

Perform FEC tests yearly for each horse.

Perform fecal egg count reduction test (FECRT) in both foals and adult horses every other year. In herds with high numbers of horses, FECRT does not need to be performed on all horses -- six is the recommended number.

For more challenging horses, make deworming time simple with a drench bit, for less stress on them -- and for you.

Rotational deworming, the practice of deworming all horses quarterly with different classes of dewormers, is no longer recommended by equine parasite experts. Rotational deworming has been found to increase risk for parasite resistance. Implement a strategic deworming program to help ensure your horse’s health and the efficacy of dewormer ingredients.

Find pictures and descriptions about worms in horses to best identify your horse’s risk. To continue learning, view this horse wormer Q&A.