When you groom your dog, pause and take a good look at his paws. Check your dogs’ nails and make sure that they’re not too long and that they are healthy.  If his nails are brittle or break frequently for no reason, it’s a good idea to get this checked out by your veterinarian.  The problem could be mange,  a fungal disease that may be  contagious. It could also indicate a nutritional disorder. Some dog breeds such as Rottweilers and Greyhounds are susceptible to an auto immune disease which can cause brittle nails. If left unattended, brittle nails can break and become painful. Take your dog in for a good physical. If necessary, your veterinarian my draw blood or may prescribe some pet medication or supplements.