Blog #6: When to deworm your horse?
When to Deworm Your Horse: A Comprehensive Guide
Keeping your horse healthy involves more than a good diet and exercise—it also requires regular parasite control. Deworming is a key part of that, as internal parasites like worms can cause serious health issues in horses. But knowing when to deworm can be tricky, as not all horses have the same parasite exposure or load. Here’s a breakdown of when to deworm your horse and why timing matters.
1. Understanding Why Deworming is Important
Horses are natural grazers and constantly ingest soil, grass, and water that can be contaminated with parasite eggs or larvae. These parasites can damage the horse’s digestive system, cause weight loss, colic, anemia, and, in severe cases, even death. Proper deworming practices reduce the risk of parasitic infections, help control the spread of worms in a herd, and support overall horse health.
2. The Problem with Over-Deworming
In the past, deworming every 6-8 weeks was the standard recommendation. However, this frequent dosing has led to an increase in resistance, meaning many common parasites have become resistant to standard deworming drugs. Rotational or scheduled deworming without a targeted plan isn’t as effective as once thought. Instead, vets now recommend a more individualized approach based on the specific needs of each horse, considering factors like age, health, season, and exposure.
3. Parasite Control Programs: The New Approach
The modern approach to deworming involves creating a targeted parasite control program based on fecal egg counts (FECs). This involves testing your horse’s manure for the presence of parasite eggs to understand the severity of the infestation and the types of parasites present. FECs guide the frequency and timing of deworming, ensuring you use the right dewormers and reduce unnecessary treatments.
A general guideline for timing:
Spring: For adult horses, a dewormer targeting strongyles is often recommended in early spring, depending on fecal egg count results. Spring is typically when parasite eggs start appearing in pasture, so it’s an ideal time for control.
Fall: In the fall, deworm with a product that targets tapeworms and encysted small strongyles. Fall treatments often include ivermectin or moxidectin, sometimes combined with praziquantel to target tapeworms.
4. Age-Specific Deworming
The age of the horse affects how often and when to deworm, as young foals, weanlings, and older horses have different vulnerabilities.
Foals (0-6 months): Foals are highly susceptible to roundworms (ascarids). Deworming should begin as early as 2-3 months, with treatments every 2-3 months until they are a year old.
Weanlings and Yearlings (6-18 months): They often carry high worm burdens and need more frequent monitoring and treatments, typically every 3-4 months.
Adult Horses (Over 3 years): Many adult horses develop a certain level of immunity to common parasites and may require deworming only twice a year, depending on fecal egg counts.
Senior Horses: Older horses may require special consideration if their immune systems are compromised. Regular fecal egg counts help in assessing their need for more frequent deworming.
5. Environmental Factors
Environmental factors, like the climate and the density of horses in a pasture, play a big role in parasite exposure. Warmer, wetter climates tend to promote faster parasite growth. In regions with harsh winters, parasite activity decreases, allowing for a reduction in deworming frequency. Here’s a season-based guide:
Spring and Summer (High Parasite Load): Increased egg shedding from parasites like strongyles makes spring a key time for deworming.
Fall (Encysted Larvae): Fall treatments can help combat any parasites that have survived the summer. Targeted treatments for tapeworms and encysted larvae help manage those specific stages.
Winter: In areas with freezing temperatures, deworming may not be necessary as parasite activity is lower. In milder climates, however, parasites may still be active, so consult your vet.
6. The Role of Pasture Management
Deworming alone won’t control parasites if the environment remains contaminated. Effective pasture management can reduce the overall parasite load:
Rotate pastures to minimize exposure to contaminated areas.
Remove manure from fields regularly, as this is the primary source of parasite eggs.
Cross-graze with other species like cattle or sheep, which do not carry the same parasites, to disrupt the life cycle of the worms.
7. When to Consult Your Veterinarian
Consulting your veterinarian about a deworming schedule is essential. A vet can perform fecal egg counts to determine your horse’s individual risk level and create a deworming program tailored to your horse’s needs. They can also help select the right dewormers for the types of parasites present in your region.
Conclusion
Knowing when to deworm your horse is a balance of fecal egg counts, age, seasonal timing, and environmental factors. By personalizing your horse’s deworming schedule and keeping up with regular manure management, you’ll be able to protect your horse from parasites effectively and responsibly.
For a healthier horse and a better-managed pasture, consider deworming an essential part of your horse’s wellness plan—one that evolves with your horse’s unique needs.