Why do dogs attack farmstock? How do I train my dog so that it will not harass sheep?
The risk of problems is probably greatest with any of the breeds that have been developed for herding purposes, such as collies or similar dogs, because they instinctively seem to recognise the ancestral link, which draws them to the animals. They may then start to eat afterbirths, attacking new-born lambs as well as harrying ewes.

It is really a matter of training your dog to return to you immediately when called, rather than trying directly not to teach it to interfere with farm stock.

You need to be aware of the risk of the danger arising, so watch out for sheep, calling your dog back to you without delay in this situation and placing it on a leash, rather than waiting until the flock is within reach.

Should your dog attack any sheep, you could be held legally liable, and may well be ordered to pay compensation should the case go to court, and your dog will have to be put to sleep.