If you own a horse, a regular deworming schedule is essential to their health. Deworming prevents parasite-related diseases, helping to prevent colic, weight loss, and other serious health concerns.
But the old, traditional ways of deworming horses are becoming less effective due to drug resistance. It’s becoming more common to use a surveillance-based approach. This means testing your horse’s manure to determine their parasite load and determine how often you need to deworm your horse.
Understanding fecal egg counts (FEC)
One of the best ways to dial in on the right deworming schedule for your horse is to have your vet perform a fecal egg count, or FEC. Here’s what you should know:
What is a fecal egg count?
An FEC measures the number of parasite eggs in each gram of manure (EPG). This test is useful for classifying your horse as a low, moderate, or high shedder.
It’s important to work with your veterinarian on this, as they are best equipped to perform and interpret FEC results. Your vet can also suggest a deworming schedule that’s tailored to your horse’s needs and the regional prevalence of parasites.
Shedder categories and their significance
- Low shedders typically have fewer than 200 EPG and don’t need to be dewormed as often.
- Moderate shedders have between 200 and 500 EPG and need a moderate frequency of deworming.
- High shedders exhibit more than 500 EPG, so they need to be dewormed more often and monitored for drug resistance.
Adult horse deworming schedule based on FEC
The best deworming schedule for your horse depends on their FEC, or fecal egg count. Here’s a general guide:
Deworming for low shedders
Horses that are low shedders typically only need to be dewormed once or twice a year, with attention paid to tapeworm treatment and encysted strongyles. A good time to deworm is in the spring and fall, depending on parasite activity in your area.
Deworming for moderate shedders
Moderate shedders usually require deworming two to three times per year. Deworming in the spring and fall is a good idea, and you may need to deworm in mid-summer based on your horse’s FEC results.
Deworming for high shedders
High shedders may need to be dewormed three to four times a year. Your deworming schedule should be based on FEC results and your veterinarian’s recommendations. It’s important to monitor for drug resistance in these horses.
It’s important to perform FECRTs, or Fecal Egg Count Reduction Tests, to make sure the dewormer is still working. If the egg count reduction is less than 90%, that could be a sign of resistance.
Deworming schedule for foals
Foals are very vulnerable to ascarids, or roundworms. Deworming should start at around 2 months old, with either fenbendazole or oxibendazole.
When the foal is 4-5 months old, ask your vet to perform fecal egg counts (FECs) to track both ascarid and strongyle levels.
At about 5 months, deworm with ivermectin to combat strongyles. At the end of the year, treat for tapeworms with a combination of ivermectin and praziquantel.
Good pasture management helps keep the parasite load down for both foals and mares.
General deworming protocol guidelines
There’s no one-size-fits-all answer to the question of when to deworm your horse. Here are some general guidelines to keep in mind.
Choosing the right dewormer
When it’s time to deworm, you’ll need to consider a few factors to make sure you’re using the most effective product.
- Talk with your veterinarian about the dewormers that work best in your region, given the types of parasites that are common and the resistance patterns in your area.
- Some of the most commonly used deworming medications are ivermectin, moxidectin, fenbendazole, pyrantel pamoate, and praziquantel.
Non-chemical parasite management strategies
There are also some non-chemical strategies you can use to manage parasites on your property.
Pasture management
- Rotate pastures to keep parasite numbers down.
- Consider cross-grazing with ruminants such as cattle or sheep to interrupt the parasite lifecycle.
- Remove manure on a regular basis to minimize parasite contamination.
- Harrow or drag pastures in hot, dry weather, and keep horses off those pastures for about two months.
- Avoid overstocking your pastures.
Other management practices
- Maintain good hygiene in your stables and paddocks.
- Make sure your horses are getting the proper nutrition to support a strong immune system.
Closing Thoughts
The best way to keep your horse healthy and parasite-free is to work with your veterinarian to develop a deworming program designed just for your horse. You can also monitor your horse’s fecal egg count (FEC) routinely and adjust the deworming schedule to minimize drug resistance and maximize parasite control.