Worm burdens in livestock can significantly impact animal health and productivity. Traditionally, chemical drenches have been the go-to solution, but overuse has led to widespread drench resistance. For sustainable parasite management, it’s essential to adopt strategies that minimise reliance on chemical treatments. This article outlines practical, evidence-based approaches to controlling worms naturally on lifestyle farms.

Why Reduce Reliance on Chemical Drenches?

• Overusing chemical drenches leads to "super worms" that are resistant to treatments. This could make it impossible to manage worm burdens effectively in the long run.

• Using non-chemical methods to manage parasites helps animals develop natural immunity and reduces stress.

 Understanding the Worm Life Cycle

Worms have a predictable life cycle that begins inside the animal, where adult worms lay eggs. These eggs are expelled in feces, hatch into larvae on the pasture, and eventually climb onto grass blades, waiting to be ingested. About 90% of worm larvae are found in the bottom 2-3 cm of grass, making grazing height a critical factor in managing worm intake.

Strategies for Managing Worms Naturally

These strategies work with the animals' natural grazing practices and immunity to help restrict the worm burden in pasture.

Species-Specific Grazing Management

• Goats are natural browsers, preferring to feed on shrubs and tall vegetation. They thrive on woody plants, such as poplar and willow, which are naturally high in tannins—substances that can help control internal parasites. To reduce worm burdens, provide goats with browse options or graze them on long, high-fibre pastures. Avoid forcing goats to graze low to the ground, where worm larvae are most concentrated.

• Sheep prefer to graze low to the ground, making them more susceptible to ingesting worm larvae. However, sheep develop strong immunity to most worms by about 18 months of age. When managing sheep, allow older animals to “vacuum” shorter grass, while keeping young lambs on longer pasture.

• Cattle also develop good immunity to worms as they mature. Like sheep, adult cattle can be used to graze down pastures after younger stock or other more vulnerable species.

• Camelids (Alpacas, Llamas) are a mix between browsers and grazers and require longer forage to maintain dental and digestive health. They all use one area in their paddock to poop in so the worms are all in one place. They don’t eat in this area so they’ve not evolved to have to deal with a heavy worm burden in their grazing. They do acquire moderate immunity to worms as they become adult but can still be vulnerable especially if sharing pasture with sheep or goats.

Cross-Grazing

Cross-grazing involves rotating different species through the same paddock to break the worm life cycle. For example:

• Follow goats with sheep or cattle. Goats consume the top parts of the pasture, reducing their worm intake. Follow with adult sheep or cattle, which can graze the pasture lower. This rotation reduces the overall worm load and disrupts the life cycle of species-specific parasites.

• Follow young stock with adults. Offer young animals long grass then follow them with adults who have developed immunity. This works for sheep and cattle but not goats as adults do not develop the same immunity to worms.

• Horses are particularly effective in cross-grazing systems because they do not share internal parasites with ruminants like sheep, goats, or cattle. Grazing horses after ruminants can help clean up the pasture without increasing the worm burden for other animals. Horses’ preference for lower pasture growth also helps to reduce worm larvae levels for subsequent grazing cycles. 

• Avoid grouping vulnerable species together. Combining species that share the same parasites (e.g., goats, sheep, and alpacas) can increase worm burdens. 

Pasture Management

• Use rotational grazing - move animals frequently between paddocks to reduce worm reinfestation. Allow pastures to rest for at least six weeks to give time for larvae to die off.

• Keeping grass at 8-10 cm or higher reduces the likelihood of animals ingesting worm larvae, as most larvae are concentrated in the lower grass.

• Designate a specific paddock for lambing, but don’t use the same paddock every year to prevent the buildup of larvae over time.

Supplementary Forage

Introducing alternative forage can help reduce worm burdens while meeting nutritional needs:

• Chicory. High in tannins and minerals, chicory can be oversown into pastures to provide a nutritious, worm-reducing crop. It’s particularly effective for growing animals and lactating females.

• Poplar and willow. These trees are rich in tannins and can be harvested to provide supplementary feed. Their deep roots also make them drought-tolerant, making them a useful summer feed source.

Note: Always feed supplementary feed in raised feeders or on dry surfaces to minimise the risk of animals ingesting worm larvae from the ground. Feeding directly on pasture increases the chance of picking up larvae, particularly when the grass is short or damp.

Shelter and Dry Environments

Providing good shelters for animals can reduce worm exposure:

• Build shelters that keep animals off wet pasture during high-risk times. Grating or other dry floors mean the worms don’t have the moist environment they need to survive.

• Clean shelters regularly to reduce worm larvae accumulation.

Natural Treatments and Supplements

• Copper Oxide Wire Particles (COWP): These can be administered to goats (with veterinary guidance) as a bolus, reducing worm burdens, especially Barber’s Pole Worm. Be cautious with sheep, as they can be prone to copper toxicity.

• Predatory Fungi (e.g., BioWorma): This fungi is added to feed and passes through the animal’s digestive system. Once excreted, it targets and consumes worm larvae on the pasture, gradually reducing the parasite load.

• Diatomaceous Earth: While its effectiveness as a worm treatment in ruminants is not fully proven, diatomaceous earth may have some impact when used as a preventative measure.

Monitoring and Fecal Egg Counts (FECs)

• Routine FECs are critical for monitoring worm burdens and making informed decisions about treatment. They help identify high-risk animals and evaluate the effectiveness of grazing management and natural treatments.

• Use FECs to guide targeted drenching when necessary, preserving chemical drenches for times of high need.

Conclusion

Managing worm burdens naturally involves a combination of strategic grazing, offering supplementary feed, and drenching only when necessary. By focusing on these holistic approaches, you get healthier animals while minimising chemical use.