News & Advice

Why do we need to worm our working dogs so regularly?

Apr 4, 2019 | Dry stock, Working Dog

I had a call from a client the other week – his young worker had left, with his dogs, and left behind a drawer full of dog worming pills, so I don’t need any more for a while thanks! And why do we need so many anyway?

While this made me laugh, it is too common a question. How many drawers are out there full of worming pills not getting into our dogs? What are we worming for and why do we need to do so monthly?

Firstly we need to explain what worms our dogs get and what the pills do. I will only mention Droncit and Drontal as they are the pills most commonly used in a farm dog program but there are other brands and types of pills, please call us if you are unsure that you are using the correct drugs.


Taenia ovis is a parasite that relies on two hosts to complete its life cycle. Eggs produced by the tapeworm in dogs are passed in faeces to pasture, where there are ingested by sheep or goats. After ingestion, the eggs penetrate the intestinal tract, are moved around the body in the blood, shift out of the blood to muscle tissues and form cysts that are infective to dogs. The dogs have to eat the infected muscle for the lifecycle to begin again.

The cysts in sheep, if not eaten by dogs, become hard and fibrous or calcified lesions, that become defects in the carcass, called sheep measles.

Sheep measles is the primary reason we worm our dogs monthly, since the lifecycle can be as short as 35 days from when a dog eats infected sheep meat to producing infective eggs. The eggs are infective on the pasture for up to 6 months.

This is also the reason we cook or freeze sheep meat before feeding it to our dogs.
The drug of choice to kill Taenia ovis is Praziquantel – the active ingredient of Droncit, which is the tablet used two months out of every three.

Tapeworms have the intermediate host of a flea and often the only clinical signs we see of this worm is actual visualisation of tapeworms in the dog’s faeces or we see them scooting. Tapeworms can also infect humans if they eat an infected flea.


Roundworms can cause ill-thrift, vomiting and diarrhoea, especially in young dog’s which is why puppies are routinely wormed two-weekly until they are 4 months old. They are caught from their mother via the milk, from the environment and especially other dogs faeces.


Hookworms infect dogs by ingestion of larvae from the environment, by larvae penetrating the skin, or in pregnant bitches through the placenta or through milk. These worms can cause a lot of damage to the lungs, and suck blood in the intestine causing anaemia. If they invade the skin en-mass they can cause skin infections. Young dogs are once again more susceptible, and humans can also become infected.

Taenia ovis, tapeworms, roundworms and hookworms can all be treated using Drontal tablets which have a combination of praziquantel, pyrantel and febantel. This is the tablet given every three months and even if you have no sheep on farm, these tablets are still recommended.

The Vetserve Worming program is a service that sends out the correctly sized tablets needed monthly in the mail. If you have sheep you will receive Droncit for two months, then Drontal the third month. If not, then you will just get the Drontal tablets every three months.

Call your local clinic today if you have any questions about the whys and wherefores of dog worming, or to sign up to the Mailout Program where you can automatically receive the tablets your dogs require to keep them, yourselves and your sheep fully protected.

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