Contrary to popular opinion, your pet actually needs regular shampooing during the winter months to keep his skin and coat healthy. In fact, done properly, a bath can help to reduce dryness, matting and related skin problems. Always follow the shampoo with a conditioning rinse or moisturizing treatment.
Don't be tempted to use your own hair care products on your pet. Animal's skin has a different pH from human skin, so choose products specially formulated for pets. If your pet's skin seems especially dry or scaly, he may need a medicated treatment. If you aren't sure which products are right for your pet, consult a professional groomer for product recommendations.
Also note you should be blow drying your dog , especially in the colder months. If your dog is a coated breed you also need to brush and comb at the same time.
Make sure you brush out all the mats before you bath them. If you do not the water will make the mats tighter.