Parasite Management in Cattle and Sheep

Parasites are considered to be one of the most economically important constraints in raising livestock. They can impact animal productivity by causing: severe scouring, Ill-thrift, reduced growth rates, loss of weight, rough coat, poor milk production and swelling of fluid under the jaw (“bottlejaw”) as a result of liver fluke.

Both internal and external parasites are developing resistance to all dewormers. Therefore we need to be using an integrated management approach encompassing nutrition, pasture management and strategic deworming use.

Major parasites in cattle include:

• Protozoa
• Roundworms in particular the small brown stomach worm
• Tapeworms
• External parasites e.g. lice, bots, ticks and flies

Major parasites in sheep include:

• Protozoa
• Roundworm in particular Barbers pole worm
• Tapeworms
• External parasites e.g. lice, blowflies, nasal bot

Nutrition 🌿

Animals that are provided with adequate nutrition have fewer worm burdens and are able to cope with worm burdens better. They are better able to endure the symptoms of worms, increasing the rate of recovery. Best way to do this is by:
• Rotationally grazing pastures between sheep and cattle. Worms are generally host-specific.

• Pastures that have not been previously grazed by any cattle for at least 4 months.

• Newly sown pastures

• High plane of nutrition – assessing body condition is a good way to determine if livestock are getting enough nutrition value

• Controlled grazing strategy: rest pastures, allow grasses to grow higher therefore better plane of nutrition

Pasture Management 🌾

The Majority of the parasite life cycle is outside the animal, and occurs within the environment. Resting pastures for significant periods allows earthworms, dung beetles other organisms and the environment to destroy parasite eggs and larvae within the environment.

~ Strategic Use of Deworming Products ~

There are three groups of drenches commercially available for the treatment of worms. Due to rising resistance it is important to rotate these classes. The three groups of drenches for worm control in cattle include:

- Group 1 (Benzimidazole or white drenches)
- Group 2 (Levamisole or clear drenches)
- Group 3 (Macrocyclic lactone or Mectin drenches)

A Drenching protocol includes drenching to the average weight range every change of season e.g. Autumn and Spring. It is best practice to change up the brands in order to prevent resistance build-up.