Ivermectin for Horses, Cattle and Sheep - A Complete Australian Guide to Safe, Effective Parasite Control (2025 Edition)

Date Posted:25 November 2025 

Ivermectin has been one of the most trusted antiparasitic medicines in equine and livestock care for more than four decades. Its broad effectiveness, reliable safety margin and ease of administration have made it a core treatment in Australian parasite-control programs. 

But while ivermectin is exceptionally useful, it is not universal, each species requires its own formulation, dosing strategy and timing.

This guide explains how ivermectin works, which parasites it treats, how to use it safely and how to choose the correct ivermectin product for horses, cattle and sheep. 

How Ivermectin Works

Ivermectin belongs to the macrocyclic lactone class, which acts on specific chloride channels in susceptible parasites. Once bound, these channels stay open, leading to paralysis and death of the parasite.

This mechanism provides broad-spectrum internal parasite control while maintaining a large safety margin when used in the species and dose for which each product is formulated.

Because metabolism varies between horses, cattle and sheep, ivermectin must always be given in species-appropriate formulations.

Ivermectin for Horses: What It Treats & When It’s Recommended

Australian horses are exposed to a wide range of internal parasites all year round. Ivermectin remains one of the most effective treatments for many of these, including:

  • Large strongyles
  • Small strongyles (including resistant strains)
  • Roundworms (especially in young horses)
  • Pinworms
  • Hairworms and threadworms
  • Lungworm
  • The larvae of Gasterophilus (bots)

When administered at 200 mcg/kg, ivermectin paste is considered safe for adult horses, senior horses, pregnant mares and breeding stallions.

For most horse owners, the most reliable choice is a high-quality equine ivermectin paste. A widely trusted option is the Equimec Ivermectin Paste 6.42 g for horses, formulated specifically for equine use and calibrated for accurate weight-based dosing.

Owners managing several horses, whether on agistment, in training or on breeding farms, often choose value pack formats. 

These are designed for long-term programs and frequent dosing based on fecal egg count guidance or seasonal needs. 

The Equimec range includes both a 5-pack and a larger 10-pack for multi-horse management.

Pro Tip:

Most horses weigh more than owners assume. Always measure with a weight tape or scale before dosing to avoid underdosing and potential resistance issues.

 

Ivermectin for Cattle - Why Injectable Formulas Are Preferred

In cattle, ivermectin provides broad-spectrum internal and external parasite control. It is widely used to target gastrointestinal roundworms, lungworms, lice and mange mites, all of which affect weight gain, feed conversion and overall herd health.

Injectable formulations ensure accurate dosing and efficient absorption, making them ideal for cattle in Australian conditions. One of the most commonly used options is the Starmec Ivermectin Injection for Cattle 500 mL, a bovine-specific ivermectin product designed for reliable parasite control across commercial and small herds.

Another (pour on) alternative product for catlle is the Ausmectin Cattle Pour On 

This formulation should not be used in horses or sheep, as concentration, carrier ingredients and metabolism differ significantly.

Pro Tip:
When worming groups of cattle, dose for the heaviest stock in the mob. This prevents accidental underdosing in larger animals.

 

Ivermectin for Sheep - Using a Drench Formulation for Best Results

Sheep are affected by their own distinct set of internal parasites, including roundworms, lungworms and nasal bot. These parasites reduce wool quality, weight gain and overall flock resilience.

For sheep, ivermectin must be administered as an oral drench designed for ovine digestive physiology. 

A suitable product is the IAH Ausmectin Sheep Drench Oral, a formulation created specifically for controlling internal parasites in Australian sheep.

Using a cattle injectable or a horse paste in sheep is not safe and will not deliver correct dosing.

Pro Tip:

Calibrate the drench gun before each session. Small dosing inaccuracies can meaningfully reduce treatment success in sheep.

 

Safe Use, Accuracy & Veterinary Guidance

Across Horses, Cattle and Sheep, Ivermectin has an excellent safety record when used correctly. Success depends on:

  • Accurate bodyweight measurement
  • Using a species-specific formulation
  • Following withholding periods for livestock
  • Integrating fecal egg counts into seasonal planning

Side effects are rare. In horses with heavy Onchocerca burdens, mild swelling or itchiness can occur due to the rapid death of microfilariae. This typically resolves on its own. In livestock, following correct dosing prevents both underdosing and toxicity.

Ivermectin Resistance - A Growing Global Concern

Parasite resistance to ivermectin has increased worldwide due to overuse and routine, schedule-based worming. Resistance has been identified in small strongyles in horses and several gastrointestinal worm species in livestock.

Modern parasite control emphasises:

Strategic fecal egg count testing

  •  Accurate dosing
  •  Good pasture hygiene
  •  Avoiding cross-species use
  •  Evidence-based rotation of active ingredients

These practices protect ivermectin’s long-term effectiveness.

Choosing the Right Ivermectin Product for Each Species

Ivermectin is extremely effective when the correct product is chosen.

The most important rule is simple: Match the formulation to the species you are treating.

For Horses

Use an equine paste designed specifically for horses, such as Equimec Ivermectin Paste 6.42 g for horses

Multi-horse owners may prefer the Equimec 5-pack or 10-pack, which offer the same formulation in larger quantities.

For Cattle

Use a bovine injectable such as Starmec Ivermectin Injection for Cattle 500 mL

Another (pour on) alternative product for catlle is the Ausmectin Cattle Pour On 

For Sheep

Use a sheep-specific drench such as IAH Ausmectin Oral Sheep Drench

Note: Cross-species use is unsafe and ineffective.

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Frequently Asked Questions (Short, Useful & Non-Stuffed)

Is ivermectin safe for pregnant mares?

Yes. Equine-formulated ivermectin pastes are considered safe during all stages of pregnancy when dosed correctly.

Can I use a cattle or sheep ivermectin product on horses?

No. Each species requires a specific formulation to ensure safety and correct dosing.

Does ivermectin kill tapeworms?

No! Ivermectin does not treat tapeworms. A different active ingredient is required.

How often should I give ivermectin to my horse?

Most vets recommend dosing based on fecal egg count results rather than a fixed schedule.

Final Thoughts

Ivermectin remains one of the most valuable antiparasitic treatments in Australian equine and livestock management. 

When used in the correct formulation and at the proper dose, it delivers reliable parasite control and supports long-term animal health.

Combining ivermectin with evidence-based parasite monitoring and species-specific dosing ensures safe, responsible and effective use across horses, cattle and sheep.

Contact us today to learn more about our products!