Although each of the five basic dog coat types has its own special grooming needs, the principles of hair growth and the factors which produce a healthy coat are the same for all of them. The coat types requiring the most routine grooming are the curly coat, the wiry coat and any long-length coat.
The main aims of grooming are to remove dead hair and to clean the skin and the living hair. Every dog has several different types of hair on its body. Hair grow in follicle complexes of several hairs per hole. In each follicle, , there is a primary, or guard hair which belongs to the dog's outer coat, and several secondary hairs which constitute the undercoat. Other more specialized and sensitive hairs -- the "tactile hairs" --are the eyelashes, the hair on the external ear, and the whiskers on the muzzle.
MOLTING
Molting is loss of hair and a change of coat which usually happens in spring and fall, lasting 4 to 6 weeks. The new coat grows in 3 or 4 months. The poodle group (non-shedding curly coat) doesn't shed any hair at all.
While your dog is molting, groom it daily. A little dandruff is no problem, but if there is an excess, bathe your dog. In the wild, a molt is provoked by changes in temperature and hours of daylight as winter comes and goes. However, smooth-coated domestic dogs are susceptible slipping into a permanent light molt. The reason isn't certain but it may be connected with central heating, artificial lighting or diet.
Long Coat with Undercoat
Breeds in this group include German Shepherd Dog, Collie, Newfoundland, Old English Sheepdog (Bobtail) and Spitz breeds. Bathe after each molting. Brush and comb the coat forwards over the head and shoulders before combing it back; brush the flanks in the direction of the "lay" of the coat. Comb the dense undercoat, especially during molting. Use a fine comb under the chin and tail and behind the ears. If the dog needs an additional bath between the two "major" seasonal ones, use a dry shampoo.
Many Old English Sheepdog owners keep their coats clipped to about 1 in. Like this, the dog is more comfortable than it would be poorly groomed. Even when groomed, it can be very uncomfortable on a hot day or in a centrally heated house. Grooming the dense coat takes up to an hour per day.
Silky Coat
Breeds in this group include Afghan Hound, Yorkshire Terrier, Maltese, Lhasa Apso, setters, spaniels and Pekingese. If neglected, these coats quickly become a mess. They all need frequent brushing to avoid mats, and relatively frequent baths. Afghans, setters and spaniels need to be stripped of dead hair every 3 months, followed by a bath. Spaniels' coats need a trim at the same time. Trim Yorkies and Maltese about 4 times a year. Some show specimens (particularly Afghan Hounds and Yorkshire Terriers need their hair oiled and wrapped in curling papers before a show).
Spaniels require special attention to feet and ears. Hair growing between the toes can become matted. Excessive hair on the ear flaps and in the ear canal can lead to diseases. Keep country spaniels well trimmed in these areas as their coats have an uncanny attraction for grass which work their way to the ear canals and can penetrate the skin between the toes.
Non-Shedding Curly Coat
Breeds in this group include Bedlington Terrier, poodles, Kerry Blue Terrier and some other breeds. These dogs don't molt, but hair growth is continuous, so they need a clip every 6 to 8 weeks. Give short parts of the coat a thorough brush every couple of days. Longer, fluffier parts of the coat need combing first. Most of the dead hairs of this type are secondary hairs, so neglect usually results in a "felt matting." The same type of hair occurs in the dog's ear canals and shed hair may be retained. So check the ears frequently to make sure they don't become plugged with wax and hair.
Puppies first clip should take place at 14-15 weeks old. The noise of clippers can frighten a young puppy, especially if it has to go away from home to be clipped. Accustom the puppy to the noise by gradually bringing an electric razor close to it and holding it against the puppy's skin.
Smooth Coat
Dogs with this type of coat have short, fine coat. Breeds in this group include Whippet, Boxer, smooth-haired Dachshund. Labrador Retrievers and corgies have longer, denser coat types. This is the easiest group to groom. The longer coats require a comb and a bristle brush, while a hound glove is sufficient for the short coats.
Wiry Coat
Breeds in this group include most of the terriers -- West Highland White Terrier, Sealyham Terrier, Cairn Terrier, Norwich Terrier, Lakeland Terrier, Airedale Terrier, wire-haired Dachshund and the schnauzers.
These dogs need regular combing to avoid mats. The coat should be stripped and plucked every 3 to 4 months, followed by a bath. Alternatively, machine clip every 6 to 8 weeks. Use scissors carefully round eyes and ears. Puppies are given their first trim around the head and tail at about 4 months.
EXTREMES
This group includes several breeds with distinctive coats. There are some breeds with very little hair, like Mexican hairless and Chinese Crested Dog. Although minimal, this hair still needs combing and brushing. Breeds like Hungarian Puli and the Komondor have dense, corded coats which should be oiled and twisted as they grow to maintain the cording. Breeders and your veterinarian can give you specialized information on dealing with any particular unusual coat.