Deworming Schedule for Horses
Keeping the parasites at bay

In fact, it is no surprise that parasitism is the most common equine disease. However, by establishing a regular deworming schedule to target and eliminate worms and stomach bots, as well as to prevent their reoccurrence, you can help keep your horse parasite-free. There are a variety of medicines, technically called "dewormers" but commonly referred to as "wormers," to help control internal parasites in your horse.

Determine your horse's deworming needs Unfortunately, there is no "one size fits all" deworming program. Every horse's situation is different, even for those within the same barn or on the same pasture. An effective deworming program needs to consider a number of factors, including:

• Age - foals and young horses are more susceptible to certain parasites.
• Location - certain parasites are more common in certain areas or climates.
• Season - certain parasites, like bot flies, are only active during certain seasons.
• Travel - horses who travel to shows may be exposed to infected horses.
• Pasture Load - more horses grazing in a given area may increase parasite exposure.
• Pasture Pals - other animals can carry parasites that may infect your horse.

Similarly, dewormers are available in paste, pellet, gel, or powder form. The type of wormer you choose may need to depend on your horse's acceptance of an oral gel or paste or if he prefers a feed additive pellet or powder. Also, keep in mind that dewormers contain different active ingredients, each of which is effective against a different type or species of worm. Some target specific parasites, such as tapeworms. Others aim to control a broad-range of worms, from large and small strongyles to pinworms and roundworms (also known as ascarids).

Choose an effective deworming schedule Basically, there are three ways to worm, or rid, your horse of internal parasites:

1. Oral broad-spectrum
2. Rotational
3. Continuous

Oral Broad-Spectrum Deworming
Also known as purge deworming, broad-spectrum deworming targets a range of commonly found parasites in various stages of the life cycle. Most of these dewormers contain the active ingredient Ivermectin. This medication is known to have the largest effect on the widest range of internal parasites, including large and small strongyles, roundworms, pinworms, and more. In fact, parasites have yet to show resistance to Ivermectin, despite its widespread use since its introduction in the early 1980s. Some Ivermectin-based dewormers, however, also contain additional medications to help control specific parasites, such as tapeworms or stomach bots (botfly larvae). Other broad-spectrum dewormers contain ingredients such as moxidectin or praziquantel to also target tapeworms. The success of broad-spectrum dewormers hinges, in part, on your horse already being infested with parasitic worms. A typical broad-spectrum deworming schedule may include:

Rotational Deworming
Also known as interval deworming, rotational deworming combines two or more purge dewormers, each used at set intervals throughout the year. Typically, this method combines a broad-spectrum wormer with a specialized wormer containing pyrantel pamoate or praziquantel, to target tapeworms, or fenbendazole, to control additional stages of strongyles, roundworms, and pinworms. In addition to helping rid your horse of specific worms, this method is also designed to help prevent parasite resistance to medications. Its success is also based, in part, on your horse already being infested with parasitic worms. Typical rotational deworming schedules may include:

OR

Continuous Deworming
Also known as daily deworming, continuous dewormers are in the form of a daily feed additive to constantly protect your horse against internal parasites. Most importantly, however, daily dewormers help prevent parasite re-infestation. They contain pyrantel tartrate, which attacks worm larvae before they can reproduce and migrate into body tissue and begin to damage internal organs. Many daily dewormers also help break the parasite life cycle by rendering manure inhospitable to parasite eggs. Usually, this method is combined with a twice-yearly broad-spectrum purge wormer to ensure complete parasite control. It is important, however, that your horse consumes the recommended daily wormer dose, which is easily top dressed or mixed with his daily grain ration. Missed doses decrease wormer levels in your horse's system and greatly affect the wormer's potency. A typical continuous wormer schedule includes:

Make your deworming program even more effective It is no secret that internal parasites are primarily transferred through manure. To that end, proper care of your paddocks, pastures, and fields is an important - but often overlooked - component of any effective deworming schedule. To ensure the maximum effectiveness of any medicinal horse wormer always:

• Clean regularly - remove and dispose of manure at least twice per week.
• Harrow pastures - break up manure piles to expose eggs and larvae to the elements.
• Rotate pastures - move horses between pastures to naturally break parasite life cycles.
• Group horses - group horses by age to maximize deworming schedules.
• Reduce pasture load - fewer horses per acre means reduced fecal contamination.
• Use elevated feeders - lift grain and hay off of the ground where parasites thrive.