The Modern Guide to Horse Deworming

Courtesy of SmartPak

 An In-depth Look at Current Best Practices

A proper deworming program is targeted to the individual horse, and is developed by performing a fecal egg count test to determine whether the horse is a low, medium, or high shedder, and then working with the horse’s veterinarian to decide what dewormer to use when.

Why Deworming is a Smart Choice

If you’re like any other horse owner who wants to take great care of his or her horse, the idea of your horse carrying a high load of parasites is enough to make you cringe. That’s because you know that preventing parasite infestation is crucial to maintaining your horse’s health. If left untreated, a high parasite load can cause things like including poor quality coat, weight loss, diarrhea, or colic. Unfortunately, the risk of parasite infestation is an inevitable part of horsekeeping.

Horses get “infected” with parasites, but it doesn’t happen exactly like getting infected with a contagious disease like influenza or rhino (Equine Herpes Virus). Horses usually get worms when they’re turned out in a contaminated pasture, or when they’re turned out with previously infected horses. A horse can even re-infect himself with his own intestinal worms (yuck!).

Fortunately, there is more you can do than cringe when it comes to parasite control. Along with using proper environmental management to reduce parasite transmission (like regularly removing manure from pastures – and not spreading it!), you can help protect your horse from parasites with a proper deworming program.

How to Deworm Your Horse

Deworming may be something you’ve been doing the same way for as long as you can remember—most likely rotating between ivermectin, pyrantel, and a handful of other products about every eight weeks or so. However, as parasite resistance and the lack of new dewormers in the pipeline become increasing concerns, more and more horse owners, barn managers, and veterinarians are rethinking the way they deworm horses. Nowadays, the new strategy in the war on parasites is targeted deworming for each individual horse. Luckily, developing a targeted deworming program for your horse is easier than it sounds! Here, we’ll walk you through the best practices for creating a deworming program that’s right for your horse.

Your first step in developing your horse’s deworming program is to have a fecal egg count (FEC) test performed. You can either have your veterinarian perform the FEC for you or, if your vet doesn’t offer FECs, SmartPak offers a mail-away Equine Fecal Test Kit. Because your results will help you make the most appropriate choices for your horse, you should plan to have your fecal egg count test run right before you plan to deworm your horse for the first time in the spring.

A fecal egg count measures the number of strongyle eggs your horse is passing in each gram of his manure. When you send a sample to your veterinarian or independent laboratory, you get back a number like 50 EPG (eggs per gram) or 500 EPG. That number tells you whether your horse is a low, medium, or high parasite egg shedder, which in turn helps you understand how to develop your horse’s deworming plan.

If your fecal egg count test comes back less than about 200 eggs per gram (of feces), then your horse is likely a low egg-shedder and only needs to be dewormed twice a year. If the results show more than 500 eggs per gram, then your horse is likely a high egg-shedder and needs to be dewormed more often, maybe four to six times during the grazing season in your area.

Keep in mind that even if your horse’s fecal comes back negative, that doesn’t mean your horse is parasite-free. Because horses are grazers, they’ll never be completely free of parasites. So, your horse with a negative fecal still almost assuredly has intestinal parasites, but those parasites simply aren’t actively shedding eggs. That’s why the American Association of Equine Practitioners (AAEP) recommends that even horses with a negative fecal be dewormed 1-2 times annually.

Once you know whether your horse is a low, medium, or high shedder, you can work with your vet to set your deworming schedule and decide what dewormer to use and how often. Depending on your horse’s individual situation, your dewormer of choice could be a paste dewormer or a combination of a daily dewormer and paste dewormers. Targeting your horse’s specific deworming requirements is the key takeaway, and those factors will vary quite a bit based on how heavy an egg shedder he tends to be, your geographic location, how often your horse is exposed to other horses, and the manure management on your farm. That’s why experts no longer recommend a “one size fits all” approach!

After you’ve put your deworming plan into action, it’s a smart idea to perform a second fecal egg count test 10 to 14 days after you’ve dewormed your horse for the first time in the spring. This is called a fecal egg count reduction test and tells you if your dewormer worked. Scientists are discovering more and more resistance to commonly used dewormers, so it’s important to make sure there are actually less eggs in your horse’s manure after the deworming.

And that’s it! Creating a targeted deworming plan for your horse really is easier than it sounds, don’t you think? In actuality, it really is less work, less expensive, and more effective than the rotational deworming program of the old days. By following the simple steps we outlined above, you’ll have a targeted deworming program for your horse in no time!