I had my dog groomed and about a week later he smelled really bad. Turns out he had a hot spot in the rectum area. I took him to the vet and she shaved the hair from his behind and gave me drops to apply and some anti biotics. He is doing great . I have never had this problem with him before. I am wondering if it was from the shampoo ? Since he is a Heavy coated dog I only have him bathed to a year. Regular brushing is also done.
