Springtime Fecal Egg Counts

Deworming is an essential part of maintaining your horse’s overall health and well-being. While it is impossible to completely eliminate parasites from a horse’s environment, implementing a strategic deworming program can significantly reduce parasite loads and minimize the risk of serious health complications. 

When parasite levels become too high, they can lead to:

1. Colic

2. Weight loss

3. Diarrhea

4. Poor coat condition

5. Decreased performance

6. In severe cases, life-threatening complications

Parasites are easily spread between horses, particularly in shared pastures. Eggs are passed through manure and develop into larvae in the environment, where they can be ingested by grazing horses. Because of this cycle, parasite control is not just about treating individual horses – it also involves managing the entire herd and environment. 

Traditionally, horse owners followed rotational deworming schedules, administering treatments at regular intervals throughout the year. However, parasites have developed resistance to many commonly used medications, making this approach less effective. Today, best practices focus on targeted deworming based on diagnostic testing rather than routine treatment. 

One of the most valuable tools in this approach is the fecal egg count (FEC). This test, performed by your veterinarian, measures the number of strongyle eggs per gram of manure (EPG). A fecal egg count helps you better understand your horse’s parasite burden and natural immunity. 

Fecal egg count results are typically categorized as:

1. Low shedders: fewer than 200-250 EPG (strong natural immunity; less frequent deworming needed)

2. Moderate to high shedders: more than 200-250 EPG (higher parasite burden; more frequent monitoring and treatment required)

It is recommended to perform a fecal egg count in the spring before the first deworming to establish a baseline. A second test should be performed 10-14 days after deworming known as fecal egg count reduction test (FECRT). This follow-up helps determine how effective the dewormer was. 

After successful treatment, the test should show:

1. A significant reduction in egg count

2. Fewer eggs present in the manure

3. Evidence that the dewormer is working effectively

If there is little to no reduction, this may indicate resistance to the dewormer being used.

When it comes to fecal testing, timing plays a crucial role. Performing tests at the appropriate times of year helps ensure accurate results and allows for effective follow-up actions.

When should you perform a fecal test for horses?

1. Spring (Primary Testing Period). As temperatures increase, parasite larvae that survived the winter become active on pasture, and horses graze more, raising their risk of exposure. Testing in the spring allows you to evaluate parasite levels following winter and identify which horses are shedding higher numbers of parasites.

2. Summer (Monitoring phase). During summer, parasite transmission often remains high, particularly in warm, humid climates. A mid-season fecal test helps you track whether parasite levels are rising and evaluate how well earlier deworming treatments worked. 

3. Fall (Critical control period). Fall is another important time for testing and treatment. As grazing continues and temperatures drop, parasite burdens can increase again. Testing during this season helps prepare horses for winter while also reducing contamination on pasture. 

4. Winter (Less useful). In colder climates, parasite activity drops off significantly during the winter. This can lead to lower fecal egg counts because worms are less active, not necessarily because they are absent.

There are several types of deworming medications available—each targeting different parasites. Common classes include macrocyclic lactones, benzimidazoles, and pyrimidines. Your veterinarian can help determine which product is most appropriate based on your horse’s fecal egg count results and any known resistance patterns in your area. Using the correct product at the proper dose is essential for effective treatment and to prevent further resistance. 

It is also important to consider factors such as your horse’s age, workload, and living conditions when developing a deworming plan. Young horses, for example, are often more susceptible to parasites and may require closer monitoring. Horses kept in high-density environments or on smaller pastures may also be at an increased risk of exposure. 

In addition to targeted deworming, pasture management plays an important role in parasite control. Simple practices can greatly reduce exposure, including:

1. Regular manure removal

2. Avoiding overgrazing 

3. Rotating pastures

Composting manure before spreading it on fields can also help kill parasite eggs and larvae, further reducing contamination. In some cases, cross-grazing with other species, such as cattle, may help interrupt the parasite life cycle since most equine parasites do not infect other livestock.

Supporting your horse’s overall health also helps improve resistance to parasites. This includes:

1. Providing balanced nutrition

2. Reducing stress

3. Maintaining a consistent healthcare routine

Regular veterinary check-ups are another important component of parasite control. Your veterinarian can monitor your horse’s health, recommend appropriate testing intervals, and adjust your deworming program as needed throughout the year.

An effective parasite control program combines strategic deworming, regular fecal egg counts, and good management practices. By taking a targeted and informed approach, you can better protect your horse’s health while also reducing the spread of parasites within your herd.