There are several reasons for your dog's coat to become knotted. It can be that he is not getting brushed frequently enough or that he been out playing in tall grasses. Or, there are some breeds that just seem to be more prone to tangling and knotting. While shaving your poor pooch seems to be the only answer, keep in mind your dog's coat is his only way to stay warm in the winter, cool in the summer, and to keep his skin protected from sunburn. You should only shave him if you cannot remove the knots or there are too many of them to simply cut them out.
Chances are good that your dog has no idea his coat is full of tangles and even if he does, he probably doesn't care. However, left alone, the knots can turn into mats that can be very uncomfortable for your pup and can hide parasites, dirt, and debris. Be sure you give your pal plenty of time to get used to the clippers before you start using them, to reduce his anxiety.
Shaving a dog with or without knotted hair can be challenging at first, but once you and your dog get used to it, it will go much more smoothly. However, you can avoid having to shave your dog often by spending more time grooming him on a regular basis.