Summer heat and humidity create the perfect storm for internal parasites, especially Haemonchus contortus, also known as the barber pole worm. For goats, these parasites can cause serious health problems with goats if not managed carefully.
But here’s the good news: with the right timing in your rotational grazing system, you can reduce parasite exposure and minimize the need for dewormers.
Let’s walk through how the parasite cycle works, how grazing timing can break it, and when (and how) to use dewormers when needed.
Why internal parasites are a summer problem
Parasites thrive in warm, moist conditions. When goats graze the same area too long, or return too soon, they’re more likely to pick up infective larvae that hatched from eggs left behind in manure.
The barber pole worm is one of the main concerns in goats. It’s a blood-sucking parasite that causes anemia, weight loss, and in severe cases, death.
That’s why it’s important to focus on rotating frequently and resting pastures long enough to let parasite larvae die off before goats return, along with letting grasses have enough time to grow.
The parasite life cycle and why rotation timing matters
Here’s a basic breakdown of the parasite life cycle from the American Consortium for Small Ruminant Parasite Control (ACSRPC):
- The cycle starts when goats shed parasite eggs in their manure.
- These eggs hatch into stage 1 larvae within 4–6 days in warm, moist conditions.
- Stage 1 larvae grow and molt into stage 2, then into stage 3, the infective stage. These stage 3 larvae are tough, they retain a protective sheath which helps them survive in the environment, even without feeding.
- Stage 3 larvae crawl up blades of grass or linger near the soil surface, especially in early morning dew or damp areas. When goats graze, they ingest these larvae.
- Once inside the goat, the larvae develop into stage 4 and 5 stages (immature and adult worms), eventually settling in the abomasum (the goat’s true stomach), where they feed and begin producing eggs, starting the cycle all over again.
Research has shown that stage 3 larvae can survive on pasture for 3 to 6 weeks, depending on heat and moisture levels. This means if goats stay on pasture too long, or return too soon, they’re re-ingesting parasites.
To break the cycle, your rest period should be at least 40–60 days in summer conditions. This gives most stage 3 larvae time to die off before goats return to graze again. Sometimes longer rest periods can be more beneficial for killing off larvae in some climates. It also allows the forage in the pasture to have enough time to regrow.
Aside from timing of grazing rotations, the height of the forage when returning matters as well. Ideally goats should be grazing forage above 8 inches, and not lower than 4-6 inches, where parasites tend to be more concentrated (Andries, K., 2013).
How to use grazing break the parasite cycle
Grazing plans can be built around short grazing periods and long rest periods. Here are some examples. Adjust as it makes sense with your climate, location and context of your farm.
| Element | Target Practice |
| Grazing time | 1–5 days per paddock, ideally 2-3 days, before larvae move out of stage 1 |
| Rest period | 30–60 days depending on climate and regrowth, possibly even longer |
| Grass height | Move goats before pasture is grazed below 4 inches |
| Pasture layout | Small paddocks for tighter control and faster moves |
This keeps the goats ahead of parasite buildup and gives time for any remaining larvae to die before returning
For more detail on planning grazing rotations visit this article here: Planning a Rotational Grazing System.
Multispecies grazing: Another natural tool
Grazing different species together or in rotation helps disrupt the parasite cycle. Goats and sheep share many of the same parasites. However, cattle, horses and even poultry do not.
So when they follow behind goats on pasture, they help clean up leftover forage without continuing the parasite life cycle.
Bonus: Chickens or ducks can also help by scratching through manure and reducing larvae in the soil.
Signs of heavy parasite load
Even with good grazing practices, it’s important to keep an eye on your herd. Signs your goats may need deworming or further evaluation include:
- Pale eyelids (FAMACHA 4–5)
- Bottle jaw (fluid under the jaw)
- Poor body condition or sudden weight loss
- Loose stool or scours
- Weakness or poor appetite
When and how to use dewormers
Dewormers are still an important tool, but they need to be used strategically. The goal is to treat the goats who truly need it, not the whole herd. Overuse is what leads to resistance, which can greatly limit treatment options.
Here are some general guidelines to follow when assessing if a goat, a segment of your herd, or whole herd may need to be dewormed. These are based on recommendations from Langston University and ACSRPC:
- Use FAMACHA scoring every 2–3 weeks in the warm season to monitor anemia (a sign of barber pole worm). Learn more about FAMACHA here.
- Only treat goats with scores of 4 or 5, unless they show other serious signs.
- Use a fecal egg count reduction test once a year to see if your dewormer is still effective. You can often work with your local veterinarian clinic to evaluate fecal samples for you.
- Avoid rotating dewormers randomly. Use effective combinations based on testing, or you could run a risk of worsen resistance.
Wormx.info, the ACSRPC website has a great dewormer chart for goats. We use this as a reference guide for our farm.
Tools to make shorter rotations easier
To rotate your goat herd regularly, it helps to have gear that’s simple to move:
- Portable fencing like the Gallagher SmartFence or netting
- Moveable shade and water setups
- A grazing map or spreadsheet to track paddocks and rest periods
- FAMACHA cards and an animal record system to monitor health
Parasites are part of raising goats, but you don’t have to be at their mercy. By rotating goats often, resting pastures long enough, and watching for early signs of infection, you can manage internal parasites and reduce reliance on dewormers. It’s about being proactive, not reactive.
References and additional reading
- Schoenian, S. Livestock parasitology 101. University of Maryland Extension.
- Zajac, A. (2013). Biology of Parasites. Virgina Tech.
- Dewormer Chart: Goats. (2024). American Consortium for Small Ruminant Parasite control.
- Hart, S. Parasite control with multispecies and rotational grazing. Langston University.
- Poudel, S. (2024). Pasture management techniques to reduce parasite loads in small ruminants. American Consortium for Small Ruminant Parasite control.
- Andries, K. (2013). Summer parasite management strategies in goat. American Consortium for Small Ruminant Parasite control.
- Targeted selective treatment (TST), including the FAMACHA system and five point check. (2024). American Consortium for Small Ruminant Parasite control.
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