Did you know that over 150 types of internal parasites can infect horses? The most common are: pinworms and large strongyles; roundworms; hairworms; stomach worms; bots; encysted small strengths; tapeworms. Horse worms can cause serious damage to horses’ vital organs, impair their growth, hamper performance, and even cause colic if left untreated.

How to Deworm Horses

First, consult your veterinarian for a faecal eggs count (FEC). This will allow you to determine your horse’s parasite burden and help you decide how often to deworm them.

American Association of Equine Practitioners Parasite control guidelines recommends that adult horses be dewormed when parasite levels are at their highest. This is usually in the spring or fall. However, some situations require horses to be dewormed twice annually. For example, if a horse is deemed high-shedder (>500 egg per gram) or if a foal or young horse is being dewormed.

Higher levels of parasite shedding can be caused by a variety of factors, which may require more treatment, such as:

Training and boarding barns that house more horses than necessary can increase parasite burdens.

Horses move around the farm to train or compete, which allows for greater contact with other horses.

Foals, weanlings, and senior horses are higher egg shedders than foals, weanlings, or geriatric horses.

High stocking density (more than two horses/acre) and nonrotated grasses have increased parasite levels.

Adult Horses

Low shedder horses (0-200 EPG) should have their hooves cleaned twice a year with Ivermectin in spring and Quest PLUS late autumn/early winter. Moderate shedders (200-500 EPG) should be dewormed 3 times per year. This schedule is the same as above, but with an additional late spring/early winter treatment with Ivermectin.

Deworming Young Horses and High-shedders

Yearlings, yearlings and 2-year-olds who shed a lot (>500 EPG) should be dewormed four times per year. Valley Vet Supply offers a convenient horse wormer package for one year. The Annual Young Horse and High Shedder dewormer pack is the best choice for high-risk horses. With guidance from the AAEP Parasite Control Guidelines, the Valley Vet Supply Technical Service Veterinarians developed the dewormer pack. It provides young horses and horses deemed high shedders with a convenient, comprehensive pack that can help to ensure their health and reduce parasite burden.

This handy yearly horse-wormer pack can be used to control parasites in yearlings and 2 year-olds. You can use the following dewormers in the package:

March 1: Ivermectin

June 1: Quest

Sept.1: Ivermectin

December 1: Quest Plus

Deworming foals

Foals are more vulnerable to parasites than adult horses. This makes their protection even more important and necessary. Ascarids (also known as roundworms) are the most serious threat to foals. Ascarids can quickly disrupt a foal’s immune system and cause respiratory problems, lethargy, colic, and even stunted growth.

This Annual Folial Dewormer Pack is a convenient way to treat foals for parasites. The Valley Vet Supply Technical Service Veterinarian Team developed the package with the AAEP Parasite Control Guidelines guidance. It contains six dewormers that can be used as follows:

2 Months of age: Oxibendazole/Fenbendazole

Pyrantel for 4 Months

6 months: Oxibendazole or Fenbendazole

Ivermectin Plus for 8 Months

Quest Plus for 10 Months

Ivermectin 12 Months

Additional Tips to Deworm Horses

To dose horses with horse wormer, you will need a weight tape (or digital livestock gauge) before deworming them. Use a weight tape to deworm horses: First, make sure your horse is straight. Next, place the weight tape around your horse’s heart girth. Then measure the distance between the tape and the horse. Finally, adjust the horse wormer paste to their exact weight.

Each horse should be subject to FEC testing annually.

Every other year, perform a faecal egg count reduction (FECRT) on both foals and adult horses. FECRT is not required for herds of horses with high numbers. Six horses are the recommended minimum.

You can make deworming easier for horses with more difficult horses.

Equine parasite experts no longer recommend rotational deworming, which is the practice of treating all horses with different types of dewormers every quarter. The risk of parasite resistance is increased by rotating deworming. To ensure your horse’s health and maximize the effectiveness of dewormer ingredients, you should implement a strategic program.