The Connection Between Manure and Worm Infestations
Horse manure is a primary source of worm eggs and larvae, which can lead to serious infestations if left unmanaged. Worms such as small redworms (cyathostomins), large redworms (strongyles), roundworms (ascarids), and tapeworms lay eggs that are excreted in faeces.
Under favourable conditions, these eggs hatch into larvae, which are then ingested by grazing horses, continuing the cycle of infection. By removing manure from paddocks using poo pickers, the life cycle of worms can be interrupted, reducing reinfection rates.
Seasonal Considerations for Worm Management
Spring: The Awakening of Worms
As temperatures begin to rise in spring, previously dormant worm larvae become active. Encysted small redworm larvae, which burrow into the gut wall during winter, begin to emerge, potentially causing severe health issues such as weight loss, diarrhoea, and colic. Increased rainfall and mild temperatures create optimal conditions for eggs to hatch and develop into infective larvae.
Regular poo picking during spring is essential to prevent larvae from contaminating pasture. Since horses often shed high numbers of worm eggs at this time, frequent removal of manure (ideally daily or at least every other day) can significantly reduce the risk of reinfection.
Summer: The Peak of Worm Activity
Warm temperatures and occasional wet conditions create an environment where worm eggs hatch rapidly and larvae thrive. Horses spending more time grazing in paddocks are at a higher risk of ingesting infective larvae.
To combat this, consistent poo picking is vital throughout summer, particularly in fields that are heavily grazed. In addition to using poo pickers, rotating pastures and cross-grazing with other livestock, such as sheep or cattle, can further reduce worm burdens by disrupting the equine worm life cycle.
Autumn: Preparing for Winter Dormancy
As the temperature cools, worm egg and larval development begin to slow, but the risk of encysted small redworm infestations increases. This is because some larvae burrow into the intestinal wall, where they remain dormant during the winter months before emerging in large numbers in early spring.
Autumn is an important time for poo picking to limit the number of worm larvae in the environment before winter arrives. Fields should be cleared of manure as frequently as possible, and targeted worm egg counts can help determine if additional worming treatments are necessary.
Winter: A Time for Prevention
Cold temperatures slow down or halt the development of worm larvae in the environment. However, manure left in the field can still harbour dormant eggs and larvae, which will become active again in spring when conditions improve.
While some horse owners may think winter is a time to reduce poo picking, continuing to remove manure regularly can help lower the overall worm burden for the coming year.
Using poo pickers in winter is also practical because frozen or dry conditions make manure removal easier compared to wetter seasons when droppings become more difficult to collect. Keeping paddocks clean throughout winter ensures that fewer worm eggs and larvae survive into the next season.
Benefits of Regular Poo Picking for Worm Control
- Breaks the Worm Life Cycle – By removing manure before larvae develop, poo picking prevents horses from ingesting infective stages of worms.
- Reduces the Need for Frequent Worming Treatments – Regular poo picking can lower the worm burden, making it possible to adopt a targeted worming approach based on faecal worm egg counts rather than routine worming, which can lead to resistance.
- Supports Pasture Management – Cleaner paddocks result in healthier grazing conditions, reducing overgrazing and the concentration of infective larvae.
- Improves Horse Welfare – Horses are less likely to suffer from worm-related health issues such as weight loss, colic, and diarrhoea.
- Environmentally Friendly – Reducing reliance on chemical wormers through effective manure management helps prevent wormer resistance and reduces chemical runoff into the environment.
