A dog's coat is an important characteristic and sign of the breed, an indicator of the health of the animal. It also performs decorative functions and protects the dog from the cold. Dog breeds are even distinguished by the length of the coat, so they are divided into long-haired, short-haired and those with medium-length coats.
The structure and function of the dog's coat
Hair or coat is one of the characteristic features of the class of mammals, which includes dogs. Initially, it performed only the function of protection from the cold, but as a result of human selection activities to breed various breeds, wool, or its absence, began to perform a decorative function as well, becoming one of the characteristics of the breed.
The coat of most breeds consists of different types of hair. They can differ in their structure, development and purpose and are divided into undercoat, guard and cover hair. The undercoat consists of downy hairs - thin, soft and short, as well as semi-downy hairs, which are more rigid. These are integumentary hairs, it is from them that most of the dog's coat consists. The undercoat plays an important role in heat conservation and is especially developed in those breeds that were bred in the northern regions.
The guard hair determines the appearance of the dog and its color, it consists of less dense, but longer and thicker hairs. The guard hair guide is located along the spine, on the dog's face and back. The dog's covering hair consists of two groups - tactile and dressing hair. The tactile hairs are the eyelashes on the eyelids and the mustache that grows next to the nose. Not all breeds have long dressing hair, they are clearly visible, for example, in Shepherd Dogs and Collies. The coat, typical of a particular breed, begins to form from the age of three months.
Dog hair structure
Each hair-strand consists of a shaft and a root. Desensitized rod, consisting of dead cells, protrudes above the surface of the skin. The root is located in the hair follicle, its bulb is located in the upper layer of the skin. In the bulb, there is a continuous process of cell regeneration, which causes hair growth. When the bulb dies off, the hair falls out, and after a while, a new bulb forms on the hair follicle that remains in its place and a new hair begins to grow. In dogs, a massive change of hairs that make up the coat occurs twice a year, due to the change of seasons.
The surface of each hair is covered with a cuticle, inside there is a medulla containing pigment, which determines the color of the dog. The condition of the cuticle is an indicator of the health of a dog, a properly selected diet for it. In a healthy dog, the coat is shiny, covered with a thin layer of fat secreted by the ducts of the sebaceous glands located in the upper layer of the skin.
