Strategic Deworming, Warning Signs and Pasture Management for a Healthier Herd

As summer show schedules slow down and horses transition from pasture to winter routines, fall is an important time to review your parasite-control program.

Warm days, cool nights, autumn rain and heavily grazed paddocks can create favourable conditions for parasite exposure across Atlantic Canada. However, effective fall parasite control is no longer as simple as giving every horse the same dewormer on the same calendar date.

A responsible program considers each horse’s age, health, environment, travel history and previous treatments. It also combines veterinarian-guided deworming with accurate dosing, proper recordkeeping and good pasture management.

Why Equine Parasite Control Matters

Internal parasites are a normal management concern for grazing horses. Parasite eggs are passed in manure, develop in the environment and may later be ingested while horses graze.

A significant parasite burden may contribute to:

• Unexplained weight loss
• Poor body condition
• A dull or rough hair coat
• Reduced appetite
• Diarrhea or changes in manure
• Poor growth in young horses
• Reduced energy or performance
• Recurring digestive discomfort
• Colic in some cases

These signs are not exclusive to parasites. Dental problems, poor nutrition, ulcers and other health conditions can cause similar symptoms. A horse showing weight loss, diarrhea, colic or a noticeable change in behaviour should be assessed by a veterinarian.

Why Fall Deserves Special Attention

Atlantic Canadian pastures can remain damp well into the fall. Moderate temperatures and moisture can allow certain parasite eggs and larvae to continue developing on pasture.

Colder weather may slow that development, but the first frost does not automatically eliminate every parasite risk.

Fall also brings several management changes:

• Horses may move from pasture into smaller paddocks.
• Grazing areas may become shorter or overused.
• Animals may gather around shared hay and water.
• Horses may return home after shows, clinics or summer boarding.
• New horses may be introduced to a barn.
• Manure may become concentrated around winter feeding areas.
• Changing weather may increase time spent in high-traffic turnout areas.

These conditions make fall a useful time to review your horse’s parasite-control plan with your veterinarian.

How to Know When Your Horse May Need Deworming

Parasites are not always easy to detect. Some horses can carry and shed parasites without showing obvious outward signs.

Possible signs that warrant a conversation with your veterinarian include:

• Unexplained weight loss
• Difficulty maintaining body condition
• A dull, rough or unusually long hair coat
• Reduced appetite
• Loose manure or recurring diarrhea
• Reduced energy or performance
• Poor growth in young horses
• A pot-bellied appearance in young horses
• Tail rubbing or irritation around the dock
• Recurrent digestive discomfort
• Pale gums, weakness or lethargy
• Visible worms or unusual material in manure
• Declining topline despite appropriate feeding

These symptoms do not confirm that a horse has parasites. Contact your veterinarian before administering a dewormer, particularly if the horse is losing weight, showing signs of colic or appears unwell.

Consider Your Horse’s Risk Factors

A horse can look healthy and still have parasite exposure. Certain management conditions may increase risk, including:

• Heavily used or overstocked pasture
• Sharing paddocks with several horses
• Grazing very short grass near manure-contaminated areas
• Irregular manure removal
• Frequent travel to shows, clinics or boarding facilities
• Recent arrival at a new barn
• Contact with horses that have an unknown treatment history
• A history of parasite problems
• An inconsistent deworming program
• Young or advanced age
• Poor body condition or existing health concerns

Foals, young horses, seniors and horses with health problems may require different parasite-control strategies. Their plans should always be developed with a veterinarian.

Why Appearance Alone Is Not Enough

A horse can appear healthy while still contributing parasite eggs to its environment. On the other hand, a thin horse does not automatically need deworming.

Giving a dewormer based only on appearance or a fixed calendar can lead to unnecessary treatment. It may also contribute to anthelmintic resistance—the ability of parasites to survive a product that was previously effective.

Your veterinarian can consider the horse’s age, health, living conditions, previous treatments and exposure risks before recommending whether treatment is appropriate.

Move Away from Automatic Calendar Deworming

For many years, it was common to deworm every horse at fixed intervals and rotate products throughout the year. Current veterinary recommendations advise against blindly treating every horse using the same repeating schedule.

A strategic parasite-control program may consider:

• The horse’s age and individual health
• Previous parasite-control history
• Pasture and housing conditions
• Travel and exposure to unfamiliar horses
• Parasites of concern
• Products previously administered
• Known resistance on the property
• The most appropriate seasonal timing
• Whether additional veterinary monitoring is needed

The American Association of Equine Practitioners advises against deworming all horses at fixed intervals year-round or blindly rotating dewormer classes.

Choosing the Right Horse Dewormer

There is no single dewormer that is automatically right for every horse, parasite or farm.

Different products contain different active ingredients and target different parasites or life stages. The product used last fall may not necessarily be the correct choice this year.

Before selecting a horse dewormer, speak with your veterinarian about:

• The horse’s age
• Current health and body condition
• Pregnancy or nursing status
• Recent symptoms or digestive concerns
• Previous products and treatment dates
• Other medications or health conditions
• Travel and show history
• New arrivals at the barn
• Parasites of concern
• Known or suspected resistance
• Appropriate timing for treatment

Never combine dewormers, change the recommended dose or give a horse a product intended for another livestock species unless specifically directed by a veterinarian.

Feeds’n Needs carries equine deworming products at select locations. Availability varies by store, and our team can help you locate the product recommended by your veterinarian.

Accurate Weight and Dosing Matter

Underdosing may result in ineffective treatment and contribute to resistance. Estimating a horse’s weight by sight can be difficult, especially when the horse has a thick winter coat or carries weight unevenly.

Use a livestock scale when available. An equine weight tape can provide a practical estimate when a scale is not accessible.

Once your veterinarian has recommended a product:

1. Read the complete product label.
2. Confirm the horse’s current weight.
3. Set the dosing syringe carefully.
4. Make sure the horse receives the full dose.
5. Confirm that the medication has been swallowed.
6. Record the product, active ingredient, dose and date.
7. Monitor the horse as advised by your veterinarian.

Never administer more than the labelled or veterinarian-prescribed amount.

Keep Individual Deworming Records

Maintain a parasite-control record for every horse rather than relying on memory or a general barn calendar.

Record:

• Treatment date
• Product name
• Active ingredient
• Dose administered
• Estimated or measured weight
• Reason for treatment
• Previous veterinary recommendations
• Reactions or concerns after treatment
• Travel and new-horse introductions
• Pasture or housing changes

Good records help prevent accidental repeat treatments and allow your veterinarian to identify patterns over time.

Pasture Management Is Part of Parasite Control

Deworming alone is not a complete parasite-control program. Horses can be exposed again when grazing contaminated areas, making manure and pasture management essential.

Remove Manure Regularly

Pick manure from smaller paddocks, dry lots and high-traffic areas regularly. Pay particular attention to:

• Hay-feeding areas
• Gates and laneways
• Shelters
• Water sources
• Small sacrifice paddocks
• Winter turnout areas

Feeds’n Needs carries stable forks, manure-handling tools, wheelbarrows and other barn-cleaning supplies that make regular cleanup easier.

Avoid Overcrowding

More horses in a limited area generally means more manure and greater environmental contamination. Avoid overcrowding whenever possible and provide enough room around hay, water and shelter areas.

Prevent Overgrazing

Horses grazing very short pasture may feed closer to manure-contaminated areas. Rest overused paddocks and provide suitable forage when grass becomes limited.

Moving hay feeders periodically can also help reduce concentrated manure and damaged ground around winter feeding areas.

Rotate Pastures Carefully

Pasture rotation can help protect forage and reduce overgrazing, but simply moving horses does not eliminate parasites.

Rotation works best when combined with:

• Regular manure removal
• Appropriate stocking density
• Rest periods for pasture
• Proper composting
• Veterinarian-guided parasite control
• Careful management of new arrivals

Quarantine New Horses

New horses may introduce parasites—including resistant populations—to a property.

Before turning a new horse out with the resident herd:

• Keep the horse in a separate area.
• Use separate buckets and manure tools where practical.
• Review its health and deworming history.
• Contact your veterinarian for an appropriate arrival protocol.
• Avoid spreading manure from quarantine areas onto active pasture.

Compost Manure Properly

Avoid spreading fresh horse manure directly onto fields currently being grazed. Proper composting creates heat that helps reduce parasite survival and produces a more useful soil amendment.

Keep compost piles away from feed and water sources and manage runoff during wet Atlantic Canadian weather.

Support Overall Health Through Fall

Parasite control is only one part of preparing a horse for winter. A horse entering the colder months in good condition is better positioned to handle declining pasture quality and changing weather.

Review:

• Body condition
• Forage quality and quantity
• Access to clean water
• Salt and mineral availability
• Dental care
• Hoof care
• Vaccination status
• Shelter and blanketing needs
• Feed changes as pasture declines

Feeds’n Needs offers equine feed, forage products, salt, minerals, buckets, weight tapes, manure forks and stable supplies to support your horse’s complete fall-care routine.

Nutritional products and supplements do not replace veterinary-prescribed parasite treatment.

Signs That Require Veterinary Attention

Do not wait for a planned deworming date if your horse develops concerning symptoms.

Contact your veterinarian if you notice:

• Colic or repeated digestive discomfort
• Persistent diarrhea
• Rapid or unexplained weight loss
• Weakness or lethargy
• Loss of appetite
• Pale gums
• Poor growth in a young horse
• Significant abdominal distension
• Sudden decline in body condition
• Visible worms accompanied by illness

Attempting to treat a sick or heavily affected horse without veterinary direction may delay proper diagnosis and care.

Fall Horse Deworming Checklist

Before administering a dewormer:

• Review your horse’s health and treatment history.
• Consider recent travel and exposure to unfamiliar horses.
• Watch for changes in weight, appetite, manure and performance.
• Discuss risk factors with your veterinarian.
• Ask which parasites should be targeted.
• Use only the veterinarian-recommended product.
• Measure or accurately estimate body weight.
• Follow the product label and dosing instructions.
• Record the product, active ingredient, dose and date.
• Monitor your horse following treatment.
• Remove manure from high-use areas.
• Rest overgrazed paddocks where possible.
• Quarantine new arrivals.
• Maintain good forage, water and mineral support.

Build a Smarter Fall Parasite-Control Program

Fall parasite control is not about automatically reaching for the same dewormer used last year. It is about considering the horse in front of you, identifying its risk factors and making informed decisions with your veterinarian.

Strategic deworming, accurate dosing, recordkeeping and responsible pasture management can help protect horse health while preserving the effectiveness of available products.

Once your veterinarian recommends an appropriate product, visit your local Feeds’n Needs for select equine dewormers, weight tapes, manure forks, buckets, stable-cleaning tools and other supplies that support responsible fall horse care. Product selection varies by location.