The puppies of large breeds are trained since they are 5 months. A muzzle is chosen according to the size of a puppies head. A blind muzzle, made of a solid piece of leather with holes for air, is supposed to be the most comfortable. A puppy should smell a muzzle before wearing. Put some delicacy in a muzzle and put it on a puppy. Then they take it off after 2-3 minutes and give the delicacy to a puppy and flatter it. Repeating this approach every day, the time of wearing of a muzzle by a puppy should be gradually prolonged. If it is made every time before walking, a puppy is not very depressed with the procedure of putting on of the muzzle and it gets used to it soon. While a puppy grows, a muzzle should be changed several times. Try to put it on in such a place, where a puppy has no chance to hide. Does your dog perform the orders? For example, call it to a kitchen and order “sit”. Put it before feeding for a minute or two and let it know that a muzzle is uncomfortable, but it is not for long and there is something good waiting after. At first a muzzle can be a little loose-fitting in the order to make it possible for a dog to half-open a mouth and take a delicacy. 

Put a muzzle on with a delicacy in your hand, then praise your dog, at once draw it away with a play, pat it, flatter, ask a couple of orders (showing delicacy in your hand) and take a muzzle off sitting a dog . It is better if you do not give a chance to a dog to take off a muzzle itself. Let it know that it is only you who takes a muzzle off and only for a good behavior, no matter what does the dog do good.