7 Deworming Foals Safely That Honor Traditional Horsemanship
Learn to safely deworm foals with methods honoring traditional horsemanship. Our guide covers crucial timing, dosage, and gentle handling techniques.
Seeing a new foal take its first wobbly steps is a sight that never gets old. That fragile new life depends entirely on you for a healthy start, and a smart deworming plan is a cornerstone of that care. This isn’t about blindly following an old-school calendar schedule; it’s about blending timeless horse sense with modern tools to protect your foal safely and effectively.
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Assessing Your Foal’s Individual Parasite Risk
Every farm is its own ecosystem. A foal born into a small, dry paddock that’s cleaned daily faces a vastly different parasite challenge than one turned out onto a lush, 20-acre pasture shared with several other mare and foal pairs. Your specific environment dictates the real risk.
Consider your property’s history. Has it been overgrazed for years, creating a heavy parasite load in the soil? Or are you managing fresh pasture that hasn’t seen horses before? Factors like stocking density, climate, and the deworming history of other horses on the property all contribute to your foal’s exposure level.
There is no one-size-fits-all deworming schedule because there is no one-size-fits-all farm. The goal is to understand your unique situation. A high-risk environment demands more vigilance, while a low-risk one allows for a more relaxed, targeted approach.
Strategic Pasture Rotation to Break Life Cycles
Parasites don’t just live inside the horse; their life cycle depends on the pasture. Eggs passed in manure hatch into larvae, which then crawl up blades of grass, waiting to be eaten. Strategic grazing is one of the most powerful, non-chemical tools you have to break this cycle.
The concept is simple: move the horses before the parasite larvae have time to mature and become infective. By rotating your mare and foal to a clean, rested pasture, you leave the developing larvae behind to die off without a host. This dramatically reduces the number of new worms the foal is exposed to.
For a small farm with limited acreage, this might not mean moving between huge fields. It could be as simple as dividing one pasture into two or three smaller sections with temporary fencing. Even giving a paddock a few months of rest, especially during the hot, dry part of summer, can significantly reduce the parasite burden on the ground.
Managing the Mare’s Worm Load Pre- and Post-Foaling
Your foal’s first exposure to parasites comes directly from its mother. A mare with a high worm burden will shed a massive number of eggs onto the pasture, contaminating the foal’s environment from day one. Managing her parasite load is a critical first step in protecting her baby.
A common and effective practice is to deworm the mare with an appropriate product right around her foaling date. This specifically targets the threadworms (Strongyloides westeri) that can be passed to the foal through the mare’s milk, causing diarrhea in the first few weeks of life. This single act of prevention can save a young foal from significant stress and illness.
After foaling, the mare should be part of a targeted deworming program based on fecal egg counts. Keeping her shedding low means the pasture she shares with her foal stays cleaner. You’re not just treating one horse; you’re managing the health of the pair and their shared environment.
Using Fecal Egg Counts for Targeted Deworming
Deworming based on a calendar is an outdated practice that has led to widespread chemical resistance. The modern, sustainable approach is to deworm based on evidence. A Fecal Egg Count (FEC) is a simple diagnostic tool that tells you what types of parasites are present and in what numbers.
An FEC involves taking a fresh manure sample to your veterinarian for analysis. The results, reported in eggs per gram (EPG), give you a snapshot of the foal’s internal parasite load. This allows you to make an informed decision: Is a dewormer needed now? And if so, which one?
This approach prevents you from using chemicals unnecessarily, which saves you money and, more importantly, preserves the effectiveness of the dewormers we have. It’s a shift from reactive treatment to proactive, intelligent management. Treat the horse, not the calendar.
The Critical First Deworming: Timing and Type
A foal’s first deworming is a major milestone, and getting it right is crucial. The primary target for young foals is ascarids, or roundworms (Parascaris equorum). These large worms can build up in huge numbers, causing poor growth, a pot-belly appearance, and even life-threatening intestinal blockage.
Foals develop immunity to ascarids as they get older, but they are highly susceptible in their first year. The ideal time for the first deworming is typically around 2 to 3 months of age. This timing is strategic—it targets the ascarids after they have matured enough to be susceptible to the dewormer but before they begin shedding large numbers of eggs back onto the pasture.
Deworming too early (e.g., at one month) is often ineffective as the worms aren’t mature enough to be killed. Waiting too long (e.g., 5-6 months) allows for a massive worm burden to build up, increasing the risk of a fatal impaction when a large number of worms die off at once.
Accurate Dosing Based on Foal’s Weight, Not Age
Giving the correct dose of dewormer is non-negotiable. Underdosing is a primary driver of parasite resistance, as it kills the weak worms but allows the stronger, more resilient ones to survive and reproduce. Overdosing, on the other hand, increases the risk of adverse reactions.
Never guess a foal’s weight. Their rapid growth makes it impossible to estimate accurately based on age alone. Use a weight tape designed for horses. While not perfectly precise, it provides a much more accurate estimate than your eye and is essential for calculating the correct dose.
Take the time to get an accurate weight, read the dewormer’s instructions carefully, and administer the full, correct amount. This simple step is a fundamental part of responsible horsemanship and ensures the treatment is both safe and effective.
Choosing the Right Dewormer for Ascarids
Not all dewormers are created equal, especially when it comes to a foal’s first treatment. Because the target is ascarids, you need a product known to be effective against them. Widespread resistance has made some common dewormers less reliable for this specific job.
The preferred dewormers for a foal’s first treatment are typically from the benzimidazole class. These include:
These drugs work by slowly starving the worms over several days. This gradual die-off is much safer for a foal that may have a heavy ascarid load, as it reduces the risk of a sudden blockage in the intestine.
Crucially, avoid using moxidectin or ivermectin for a foal’s first deworming if a heavy ascarid burden is suspected. These chemicals cause rapid paralysis and death of the worms. In a foal with a large number of ascarids, this can create a massive, tangled ball of dead worms, leading to a deadly impaction colic.
Manure Management for a Cleaner, Safer Paddock
The most effective dewormer you have is a manure fork. Removing manure from your foal’s paddock is the single most impactful thing you can do to reduce parasite exposure. Each pile of manure can contain thousands of parasite eggs that will soon contaminate the surrounding grass.
For the hobby farmer, this doesn’t require fancy equipment. A wheelbarrow and a rake, used consistently a few times a week, can keep a small pasture or paddock remarkably clean. By removing the manure, you remove the source of future infections.
Properly composting the manure before spreading it on fields is also key. The heat generated during the composting process effectively kills most parasite eggs and larvae, turning a biohazard into a valuable soil amendment. This closes the loop, creating a healthier environment for your horses from the ground up.
Raising a foal is about thoughtful stewardship, not just following a formula. By combining smart pasture management, targeted testing, and the right treatments at the right time, you honor the traditions of good horsemanship while giving your foal the safest, healthiest start in life.
