Instructions
Teach your dog the "off" command so you can stop him from chasing when it is inappropriate. Begin training in an area that is free from distraction.
Put your dog on leash and show him a ball. Throw the ball in front of him where he can see it.
Give the "off" command. Pull firmly on the leash, as soon as the dog starts to go towards the ball. When the dog stops, tell her she is a good girl and give her a treat.
Repeat this several times, tossing the ball and saying "off" until the dog no longer tries to chase the ball.
Release your hold on the leash, but leave the leash attached to the dog's collar and dragging behind her. Repeat the training above several more times. If the dog starts to go towards the ball, pick up the end of the leash and stop her.
Progress to the next step of the training by replacing the ball with an animal. When the animal walks or runs by the dog, give the "off" command. If the dog starts to chase, tug on the leash and say "off" again.
How to Stop a dog From Chasing Other Animals
Many dogs love to chase. Some dogs chase anything that moves, while other dogs pick something specific that they routinely chase, such as cars or cats. Although chasing can be a lot of fun, it should be limited to play time when your dog is allowed to chase a stick or ball that you throw for him.