Intestinal Parasites and Deworming Recommendations:

Intestinal parasites plague all of our horses. Even seemingly healthy individuals can carry a heavy and potenially dangerous parasite load, so effective parasite control is an essential component of successful managment. There are over 150 species of internal parasites that can infect horses. The most common types are large strongyles (bloodworms or redworms), small strongyles, roundworms (ascarids), tapeworms, lungworms, pinworms, bots, and threadworms. The first four types are the most common and most important in terms of health risks. 

Signs of parasitism include:

 - Dull, rough haircoat
 - Lethargy (decreased energy) or depression 
 - Decreased stamina 
 - Unthriftiness or loss of condition 
 - Slowed growth in young horses
 - Pot belly (especially in young horses)
 - Colic 
 - Diarrhea


Parasite lifecycles:

There are a variety of different parasite lifecycles, but most involve three life stages - eggs, larvae (immature worms) and adults (mature worms). Eggs or larvae are shed in the manure and infect the ground, paddock or pastures. Horses swallow these eggs or larvae while grazing. The larvae mature in the horse's gastrointestinal tract and the cycle begins again. Some larvae migrate out of the intestines and into other tissues or organs before returning to the intestines to fully mature. Some parasites even lay dormant or "encysted" in the intestinal wall while maturing and can cause extensive damage when they emerge or "hatch". These parasites are immune to dewormers while encysted. Because different parasites have different lifecycles, there are different periods of time when they are susceptible to dewormers. Knowing what types of parasites are infecting your horse will help you determine what type of deworming protocol you need.

Fecal examination:

The first step is having your veterinarian run a fecal examination with a fresh fecal sample. This is a microscopic examination of fresh manure for parasite eggs. Depending on your managment style, we may recommend you test every horse or test a few horses as a sample of the larger population. Once we know what type of parasites are infecting your horse, we can evaluate your current deworming protocol and make recommendations. 

Dewormers:

There are a number of different dewormers or anthelmintics available. Most are broad-spectrum, meaning they are effective against several different types of parasites. We generally recommend using a broad-spectrum dewormer as the basis of your deworming protocol. There are generally three types of deworming programs:

1. Continuous - Feeding a daily dewormer (like Strongid C) year-round or throughout the grazing season.
2. Interval - Deworming at regular intervals or 1, 2 or 3 months, depending on the product and management system
3. Strategic - Deworming only at certain times of the year 

You can also have a combination of these programs and say for example, strategically deworm for bots if you are using a continuous deworming. The important point to understand is that there is no single deworming protocol that suits all horses or management situations. We can help you design one that is specific to your management needs. 

Good pasture and manure management:

Because parasites are spread through manure, another equally important part of an effective deworming protocol is good manure management. We recommend that you:

- Pick up and dispose of manure regularly
- Do not spread manure on fields. Instead compost it away from the pasture.
- Keep the number of horses per acre of pasture to a minimum to reduce overgrazing and minimize pasture contamination with eggs and larvae
- Keep foals and weanlings seperate from older horses to minimize the risk of infection to the more suseptible population
- Use a feeder for hay and grain rather than feeding on the ground
- Consult with your veterinarian to evaluate the effectiveness of your deworming protocol

If you have any questions or concerns about intestinal parasites and deworming, please contact us at the number below.