Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds.

Collie breeds have spread through many parts of the world (especially North America and Australia), and have diversified into many varieties, sometimes mixed with other dog types.

[1] Alternatively it may come from the related word coolly, referring to the black-faced mountain sheep of Scotland.

Collie-type breeds are also known for their sensitivity and awareness of emotions in people;[4] they may require gentler handling than other types of dogs.

Working collies display a keen intelligence for the job at hand and are instinctively highly motivated.

All collie dog breeds have proved to be highly trainable, gentle, loyal, intelligent, and well suited as pets.

The novels of Albert Payson Terhune, which were very popular in the United States during the 1920s and 1930s, celebrated the temperament and companionship of his early AKC collies.

More famously, the temperament and intelligence of the Rough Collie were exaggerated to mythic proportions in the character Lassie, which has been the subject of many films, books, and television shows from 1938 to the present.

While the dogs who played Lassie on-screen were from AKC lines, the actual Tootsie looked nothing like them, although she did come from a collie breeder.

[9] In addition, the intestinal functional system of this breed is also very fragile, and compared with similar medium and large dogs, they are easy to receive food stimulation, which leads to vomiting and excretion abnormalities or gastrointestinal diseases.

Therefore, breeders need to ensure strict hygiene for dogs to eat fresh ingredients, and rich nutrition.

[11] Canine familial dermatomyositis is an inherited idiopathic condition affecting the skin and muscle and in rare cases the blood vessels.

The condition causes dermatitis throughout the body and proceeds to myositis which in severe cases leads to megaesophagus.