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How to Keep Parasites at Bay for Your Cow

Pests and parasites aren’t just annoying—they can seriously affect your cow’s health, milk production, fertility, and more. Here’s how to create a simple, effective plan to protect your herd.

Parasites can impact your cow in many ways, including reducing milk production.

Why Parasite Control Matters

From biting flies and lice to internal worms, parasites come in many forms. Left unchecked, they can impact:

  • Milk production
  • Fertility and calving success
  • Weight gain and body condition
  • Skin and coat health
  • Overall immune function

Whether you’re managing a family milk cow or a small herd, preventing parasites doesn’t have to be complicated—it just takes a clear plan.

Conventional Parasite Control

Many dairy farmers rely on proven products to manage pests:

  • Pour-on insecticides
  • Medicated feeds
  • Insecticide ear tags
  • Sprays and dusts

Internal parasites are typically treated with medications such as:

  • Benzimidazoles
  • Macrocyclic Lactones
  • Levamisole
  • Monepantel
Many dairy farmers rely on products such as medicated feeds to manage pests.

💡 Always follow the dosage on the label and consult your vet for proper use.

Holistic & Natural Approach

If you prefer a more natural or chemical-free approach, consider these options—either on their own or in combination with conventional methods.

Diatomaceous earth can be applied to your cow’s coat or her loafing areas.

Diatomaceous Earth (DE)

What it is: 

A fine powder made from fossilized algae.

How it works: 

Destroys insect exoskeletons, causing them to dehydrate.

How to use it:

  • Dust on your cow’s coat
  • Sprinkle in bedding or around loafing areas

Essential Oils (EOs)

Essential oils such as oregano, thyme, lemongrass, and tea tree offer powerful parasite-fighting properties.

Use with caution:

  • Always dilute with a carrier oil before applying to skin.
  • Use in homemade fly sprays.
  • Some oils may be given orally, but always check with a veterinarian.
Essential oils such as oregano, thyme, lemongrass, and tea tree offer powerful parasite-fighting properties.

Medicinal Herbs

Some cows instinctively choose what they need when given access to a variety of herbs.

Offer fresh or dried herbs—or plant them directly in pasture so cows can self-medicate.

Herbs to consider:

  • Oregano
  • Thyme
  • Wormwood*
  • Garlic
  • Fennel

*Wormwood is not safe during pregnancy; it can cause miscarriage

Apple Cider Vinegar (ACV)

Benefits:

  • Aids digestion
  • Boosts immunity
  • Improves skin and heart health
  • Deters internal parasites

How to use:

  • Add 1–2% ACV to your cow’s water (or a generous “glug glug” per trough)
  • Always choose raw, unfiltered, organic vinegar
One benefit of apple cider vinegar is deterring internal parasites.

Rotational Grazing

Rotational grazing helps break the parasite life cycle and promotes pasture health.

How it works:

  • Move animals between paddocks
  • Let pastures “rest” between grazings
  • Reduce overgrazing and exposure to parasite-heavy plant bases

Considerations:

  • Electric fencing is ideal for flexible setups
  • Rest times vary by climate, species, and land availability
An example of rotational grazing paddocks at Better with Thyme

Final Thoughts

There’s no perfect formula for everyone. The best parasite control plan is one that fits your farm, your philosophy, and your cows.

Whether you choose conventional treatments, holistic remedies, or a smart combination of both—stay consistent, observant, and proactive.

About the Author

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Marie Tieleman, Director of Communications ​Ever Green Acres Farm, Alberta, Canada has written 3 posts.

Marie was born and raised in the Netherlands and has a varied background. Her experience spans psychotherapy, Human Resources, working at a variety of farms and dairies, and rehabilitating troubled horses and dogs. Marie is a skilled cheesemaker, sourdough baker, and inventive cook who is inspired by historical food traditions from around the world. She relocated to Central Alberta, Canada, with her partner, Edwin, in early 2018 to start their homestead on 80 acres. Edwin works as a software developer from home while Marie operates the farm. With the help of Kate, Marie’s best friend and right hand, she makes hay for their cattle and produces much of their own food, including making dairy products, harvesting all their own meat, and tending the large vegetable garden. Maremma Sheepdogs guard the livestock, including Miniature Jerseys, Galloway cattle for beef, dairy goats, horses, Kune Kune pigs, meat rabbits, and a variety of poultry.

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