A Yorkshire Terrier's tail can be docked at any age but is often done when puppies are only days old. Older puppies or adult Yorkies can still get them docked as long as they can find a licensed veterinarian that will handle the procedure. Though docked tails remain a breed standard according to some clubs (including the AKC) in the U.S., there are other clubs that have changed this to only allowing natural tails, especially those in countries such as Belgium, German, and Switzerland where the procedure is illegal.
Most non-surgical tail docking is done within the first few days of a puppy's life. The nerve endings have not fully formed yet and so the amount of pain experienced by the dog is minimal. As the puppy grows, they gain pain receptors in the tail and the likelihood of them experiencing extreme discomfort during the docking process heightens.
Methods of tail docking
There are two procedures used to dock a puppy's tail. The first involves cutting off circulation to the top portion of the tail until the lack of blood flow causes it to "die" and fall off. This process is done within within two or three days after a puppy is born. The other procedure involves the surgical removal of the top portion of the tail and must be performed by a veterinarian. If done within the first week of a puppy's life, little to no anaesthesia needs to be used. If they are older, the procedure will be more painful and they must be fully anesthetised.
Anaesthesia can be dangerous when used on puppies. Too much of it can make them seriously ill or even cause their death. If a Yorkie is not taken in for a surgical docking procedure when they are only a few days old, it is recommended by veterinarians and breeders that they not be taken in until after at least ten weeks. This gives them time to grow and become healthy and strong enough to handle the use of anaesthetic.
When Yorkies were first bred, they were used to hunt rodents and other animals that live in tunnels. Docking their tails kept them from getting injured or broken in tight spaces. Over time, these dogs stopped being used as hunters and served more as companion animals. Docking their tails, while a breed standard of the AKC and other kennel clubs, became a cosmetic enhancement only.