There are tell-tale signs a canine reveals just before the attack, and you need to know these signs if you have any hope of success in defending against it. When a dog foams at the mouth, it's going to attack; when a dog scratches at the ground, staring menacingly into your eyes, it's going to attack; when a dog howls at the moon, it's going to attack; when a dog barks at you, it's going to attack; and when a dog sniffs the air in your direction, it's going to attack.
First, we're going to look at the attacking Collie and the techniques it implements during the attack. A Collie is a breed covered in a thick coat of down like fur; don't be fooled by this soft, fuzzy facade. A Collie, beneath the cuddly exterior, is an animal quivering with thick muscle and reinforced bone that can be used to savage it's victim in a matter of seconds. The Collie usually foams at the mouth before it attacks, this is due to its diet of mostly milk proteins. the proteins gurgle to the surface when a Collie becomes enraged, producing a milky froth that surrounds the animal's muzzle. If you keep your wits about you, you'll have no problem stopping the animal before it can clamp it's jaws around your throat.
The Collie will first dart away from you after it produces it's froth, giving you the sense that the animal is retreating. It will circle around the house after you've relaxed, hoping to take you from behind, unaware. Simply turn around and wait for it to emerge from the other side. You should have time to procure a branch or garden tool. When the Collie shows itself, only to find you facing it, it will become alarmed and hesitate for a second or two, that's the moment you need to strike. Raise the shovel (or the tool you've chosen), and rush the animal, shouting as loud as you can; or scream, either will do as long as it's extremely loud. The Collie will raise up on its hind legs as though it wants to lick your face or give you a doggie hug, If you falter at this deception, you're doomed. Feint low and let the dog descend toward your exposed head, when the beast opens its maw, immediately drop and roll into the hind legs. the Collie has weak rear legs and will be knocked for a loop, landing on its side or back. Twist up as quickly as possible and bring your weapon down onto the Collie's head. That's it, you've won. If the Animal has survived the initial blow, give it a second, or even a third whack; however many times it takes to finish it off. You'll have plenty of time to do this as the dog will be rendered senseless from your first assault. so don't overdo it, take a few breaths and access the situation, then finish the job once you feel refreshed.
After the job is done call Animal Control to help dispose of the carcass. If you feel up to the task, you can always dump the corpse in a river or leave it the woods to let nature take its course. This is the green option if you're into conservation. A bonfire is another method of animal disposal, but this tends to be only for someone living in a rural setting.
I've included a youtube video to familiarize you with the Collie so you'll be able to recognize the animal once encountered.
Next time we'll discuss how to dispatch the attacking bulldog. This is a unique attack pattern I think you'll find very interesting.