I love dogs, especially collies!  Are you a dog lover?
I am a dog lover actually. Collies are some of my favorite dogs. It's amazing how they are used as a herding dog.
What is a herding dog?  I am unfamilier with that term.
Herding dog
A herding dog, also known as a stock dog or working dog, is a type of pastoral dog that either has been trained in herding or belongs to breeds developed for herding.
Herding behavior.
All herding behavior is modified predatory behavior. Through selective breeding, humans have been able to minimize the dog's natural inclination to treat cattle and sheep as prey while simultaneously maintaining the dog's hunting skills, thereby creating an effective herding dog.
Dogs can work other animals in a variety of ways
collies became very fashionable. In the 1960s, the collie was much taller and bigger than it is today. Decades ago, collies were used for herding but they were replaced by Border Collies, it caused some collies to lose their herding instinct.
Temperament.
While often used as a working, herding dog, many are kept as family pets, as they are friendly and good with children. This type of dog is also friendly with other dogs and even non-canine pets.
Height, weight.