There are many reasons why dogs become aggressive toward other animals. Aggression can be a way for dogs to show dominance over other species, or they may become aggressive for territorial reasons. Aggression can even happen when a dog is afraid, or because of natural instincts that they have. Unchecked aggression toward other dogs causes problems and is a major concern for owners.
Let your dog know you are in charge. Use firm training methods to teach your dog you are in charge. Do things like entering a room in front of your dog, not allowing your dog to roam free, keeping them off furniture and making sure you eat before feeding your pet to show them you are in charge.
Socialise your dog with other animals at a young age. Start introducing your dogs to other animals in a controlled environment. Keep them leashed, so easy resolution of dangerous situation is possible. Start teaching them to play with other animals in a non-aggressive manner and punish aggressive outbursts toward other dogs with a timeout or gentle tap on the nose.
Train your dog not to be aggressive toward other dogs at a young age. Do not allow dogs to bite humans or other dogs while playing. Gently tap your pet on the nose and say no in a firm voice to let them know this is bad behaviour. Puppies that are biting dogs while playing should be placed in a kennel away from the group as a timeout for a minute or two. Spraying a puppy in the face with water from a spray bottle is another method to discourage biting. Never play tug-of-war or showcase aggressive behaviour with a young puppy or they will think aggression is an OK behaviour.
Reward proper behaviour with a treat. Many professional dog trainers use a counter-conditioning plan on dogs to break aggression toward other dogs. Give your dog a treat every time a trigger object that causes aggressive behaviour approaches. For example, if you are walking your dog and your dog lunges, growls or tries to bite approaching dogs, give them a treat every time your dog sees an approaching dog. Soon your dog will associate approaching dogs with a treat and your dog will look to you instead of trying to bite an approaching animal.
Make an appointment with your veterinarian. Spaying or neutering a dog can help eliminate aggression toward other dogs. It helps eliminate competitiveness in dogs of the same sex and will help eliminate a dog's need to be aggressive for mating purposes. Sudden aggression in older dogs can be a sign of a medical problem, and a veterinarian will be able to diagnose any medical conditions leading to a sudden onset of aggressive behaviours.
A retractable leash can be useful when introducing your dog to other dogs. It gives your dog more freedom of movement, yet lets you control the situation if necessary. Status or Dominance Aggression can be reduced by neutering your male dog.
Physical abuse of an aggressive dog will not change the behaviour and will lead to more aggressive behaviour from your dog.