Farmers are warned they should take every step possible to ensure dogs which have not been treated for sheep measles do not get on to their properties.
Sheep measles is the common name given to lesions in sheep meat caused by a tapeworm parasite, the primary stage being a tapeworm which infects dog intestines.
Eggs produced by the tapeworm in dogs are transferred to pasture where they are ingested by sheep.
There is no risk to human health but proliferation of the worms and cysts leads to downgrading of carcasses, or in the worst cases condemning of sheep, with consequent devastating impact on the bottom line.
Dogs should be dosed at least 48 hours before entering properties, Mr Lynch says.