Anxiety, is the anticipation of future dangers from unknown or imagined origins that result in normal body reactions (known as physiologic reactions) associated with fear; most common visible behaviors are elimination, destruction, and excessive vocalization (i.e., barking, crying). Separation anxiety is the most common specific anxiety in companion dogs. When alone, the animal exhibits anxiety or excessive distress behaviors.
While it is best to start training your pup at an early age, you can train also train an adult dog to protect your children. It's just a little harder and may take more time. Bear in mind, you instill a sense of loyalty by the way you treat your pup. The more loyalty he feels towards you and your family, the more naturally protective he will be and the easier it will be for you to train him. 
Every dog needs to learn to walk on a leash. Besides the fact that most areas have leash laws, there will be times when keeping your dog on a leash is for his own safety. Learn how to introduce your dog or puppy to the leash, then teach him how to walk properly on the leash. A loose leash walk teaches your dog not to pull or lunge when on ​the leash, making the experience more enjoyable for both you and your dog.
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