Horse Wormers

Horse Worming: An Essential Guide

Worming horses can seem bewildering at times, especially as over time guidance can alter to the approaches to risk and resistance. 

While this information we provide is expert guidance, real life scenarios can be confusing, please contact our expert team for individual tailored plans suited to your situation.

Adult horses generally require a minimum of one to two treatments annually, targeting both strongyles, including small redworms in their encysted stages and large redworms, as well as tapeworms.

Assessing a Horse's Parasite Risk Profile

Risk Factors C.A.N.T.E.R 

It is recommended to do a parasite risk assessment before buying a wormer 3

Clinical Background (C)

• Low Risk: Absence of prior worm-linked gastrointestinal issues.
• Moderate Risk: Occasional cases of worm-related gastrointestinal problems, possibly along with other health concerns such as PPID.
• High Risk: Frequent and evident gastrointestinal issues due to worms, often co-occurring with other health conditions, notably PPID.

Age Demographics (A)

• Low Risk: Age range of 5-15 years, absence of youngstock.
• Moderate Risk: Age spectrum from 5 years to senior horses, excluding youngstock
• High Risk: Young horses (1-5 years) and elderly horses with additional health issues.

Horse Population Density (N)

• Low Risk: Spacious accommodation (over 2 acres per horse)
• Moderate Risk: Moderate space allocation (1-2 acres per horse).
• High Risk: Congested living conditions (under 1 acre per horse).

Diagnostic Outcomes (T)

• Low Risk: Individual horses consistently exhibit low worm egg counts; tapeworm and small redworm antibody results are minimal. Similar low trends observed in herd-level results
• Moderate Risk: Individual horses show low to medium worm egg counts and antibody results for tapeworm and small redworm. Herd results mirror these findings.
• High Risk: Elevated worm egg counts in individual horses, with significant tapeworm and small redworm antibody results. Herd data reflects high levels. Presence of wormer resistance confirmed via reduction tests in egg counts.

Environmental Considerations (E)

• Low Risk: Isolated herd, diligent manure management (biweekly or more), and strict quarantine protocols.
• Moderate Risk: Infrequent new arrivals, less frequent manure management, and variable quarantine practices.
• High Risk: Regular herd turnover, irregular or absent manure management, and lack of quarantine protocols.

Risk Assessment (R)

• We recommend to establish the risk profile by tallying the applicable factors in each category. A higher count in the 'Low Risk' category indicates a lower overall risk factor.

Treatment Schedule

New Horses

When acquiring new horses whose worming history is unclear, it's important to initially isolate them and conduct a Faecal Worm Egg Count (FWEC) test. On their arrival, it's also advisable to either test or administer treatment for tapeworm and encysted small redworm. Subsequently, keep these horses in stables for a minimum of 48 hours. This practice helps prevent the introduction of resistant worms to your facility.

Foals

For foals and youngstock under 3 years old, we recommend a specific worming schedule:

• At 2-3 months: Treat for large roundworm using Fenbendazole or Pyrantel.
• At 5 months: Continue treatment for large roundworm, specifically with Fenbendazole.
• At 6 months: Conduct a Faecal Worm Egg Count (FWEC). If the count is positive for strongyles, use Equest.
• At 9 months: Focus on primarily strongyles, with the potential for encysted small redworm (ESRW) and tapeworm, using Equest or Equest Pramox.
• At 12 months: Continue targeting primarily strongyles, considering ESRW and tapeworm. Suitable treatments include Equest or Equest Pramox.

Youngstock

For managing the worming of youngstock, we suggest two main approaches:

1. Three Annual Treatments:

   • Administer treatments in spring, summer, and autumn.
   • In autumn, consider a larvicidal treatment using Equest or Equest Pramox.
   • Throughout the grazing season, use Faecal Worm Egg Counts (FWECs) to assess the effectiveness of the treatments and determine if additional treatments are needed.

2. Monitoring and Targeted Treatments:

   • Implement a larvicidal treatment in autumn, using products like Equest or Equest Pramox.
   • Regularly conduct FWECs during the grazing season. This helps monitor the efficacy of the treatments, particularly focusing on the Egg 4  Reappearance Period (ERP) of the last drug used. This approach aids in identifying when additional treatments are necessary.

Most treatments for youngstock will likely be from the macrocyclic lactone group, due to its high effectiveness.

Essential Guidelines for Effective Pasture Management

1. Consistent Removal of Horse Manure: Aim to clear horse waste from the fields at least bi-weekly. This practice is crucial for maintaining hygiene and health standards in the pasture.

2. Introduce Mixed Grazing: Incorporate cattle or sheep for grazing alongside horses. This diversification can benefit the pasture's health and soil quality.

3. Implement Pasture Rotation: Allowing periods of rest for your pasture is vital. This practice enables the grass to recover and grow more robustly.

4. Harrow and Rest Combination: Pairing harrowing with rest periods aids in rejuvenating the pasture. This method helps in evenly spreading manure and aerating the soil.

5. Avoid Overcrowding: Be mindful of the number of animals in each paddock. Overstocking can lead to overgrazing, damaging the pasture's health and sustainability.

Encysted Small Redworm

As the leaves fall and temperatures drop, equine health can be at risk from parasitic infections especially encysted small redworm. Worm infestation can be a year-round concern but is especially pertinent as we transition into the colder months. Horses under 5 years old, as well as senior equines over 15 years, are particularly vulnerable due to their less robust immunity. To find out more please see our encysted small redworms in horses information and video with Ben Watson SQP at Hyperdrug and Wendy Talbot of Zoetis UK - National Equine Veterinary Manager - RCVS ECEIM equine internal medicine specialist on Encysted Small Redworm. Buy horse wormers for encysted small redworm licensed in the UK. Moxidectin-based wormers Equest or Pramox, are suitable for this time of year, as they cover encysted redworm which is a colder weather and winter concern, a wormer such as Equest Pramox, also treats tapeworm and is fully licensed for use in breeding, pregnant, and lactating mares. The Panacur 5 day course, also effectively manages encysted redworm but there is widespread benzimidazole resistance of the active ingredient, and does not treat for tapeworm if required.

Tapeworm

Tapeworm affects up to 69% of horses in the UK and can be treated at any time of year, but most commonly in autumn and spring. Single dose wormers are often preferred during this time and more effective than double dose treatments, which may only target two species of tapeworm. Combination horse wormers containing ivermectin or moxidectin can address multiple parasites, including the three species of tapeworm, unlike double dosing with pyrantel embonate that will only treat one. To test your horse for tapeworm, consider the Equisal tapeworm test kit.

Grazing Season Routine

While Ivermectin wormers are effective against bots and some redworm stages, they don’t target encysted redworms, which are a particular concern in colder weather. Considering the change of season, we recommend worm egg count testing to help identify the most suitable wormer for your horse at this time of year.

Understanding Faecal Worm Egg Counts (FWECs) in Equine Care

Faecal Worm Egg Counts, worm egg count testing commonly referred to as FWECs, are tests that determine the quantity of worm eggs present in a horse's faeces. This measure provides an insight into the extent of a horse's internal worm infestation and its potential impact on contaminating pastures.

Optimal Timing for FWEC Testing

1. Seasonal Testing: In the warmer months of spring and summer, FWECs are particularly useful for determining the need for deworming treatments, especially against redworms.

2. Testing Frequency: The ideal frequency for FWECs can vary based on each horse's unique situation. Generally, conducting these tests every two to three months is a recommended starting point.

3. Action Threshold: If a FWEC reveals more than 200 eggs per gram in the horse's dung, veterinary advice and treatment are usually suggested to manage the worm burden effectively

Overview of the Antibody Test for Horses

The antibody test, conducted through blood or saliva samples, is designed to detect exposure to tapeworms by assessing the levels of antibodies present. Additionally, this test can be employed to identify small redworm infections, including Encysted Small Redworm (ESRW).

Interpreting Test Outcomes

The course of action following your horse's FWEC or antibody test hinges on the results. Based on these findings, you might receive recommendations to either administer specific treatments or schedule a re-test at a later date to monitor the horse's health status.

Finding Your Horse's Weight

Accurate dosing of wormers is crucial to prevent resistance and ensure effective treatment. Determining your horse's weight is the first step. Use our weight measure tape for an accurate measure, which helps in calculating the correct dosage of wormers.

Further Horse Wormer Guidance

For tailored advice on the best worming strategies this season, please contact us on 01833 641112 or email sales@hyperdrug.co.uk and one of our pharmacists or veterinary sqps can offer expert advice on horse wormers, as well as worming foals and donkey wormers.

A complete range of horse wormers including single dose and yard packs. Remember encysted small redworm should always be treated in the colder months.

In addition to horse wormers, we also provide canine and feline wormers, ensuring all your pets are protected from parasitic threats as we head into winter.

Many thanks to Dr Wendy Talbot RCVS ECEIM equine internal medicine specialist for helpiing Ben Watson, and team of Hyperdrug produce this expert guidance.

References and Further Information

1. American Association of Equine Practitioners (2019), "Parasite Control Guidelines."
2. Austin Davis Biologics, available at www.austindavis.co.uk.
3. Canter for Horses, accessible at www.canterforhorses.org.uk.
4. Nielsen, M. (2016), "Proceedings of the ECEIM Congress."
5. Matthews, J.B. (2017), "Veterinary Times," February 27th edition.