My friend went to Germany and asked when he came back why many German dogs had no tails. In fact, they did not have tails, but had tail-cut surgery. Some people say that tail-cutting surgery can reduce the chance of dog injury, but this statement is obviously not supported by the public, and many European countries are currently banning this surgery.
Since the tail-breaking surgery does not bring much benefits to dogs, why do many dogs have tail-breaking? Generally speaking, most of the tails that perform tail-breaking surgery are working dogs, because their tails are redundant for work, and they may not be able to continue work due to injuries, so the working dogs will be cut off shortly after birth. Similarly, the ear cutter can be seen. Nowadays, many pet dogs have their tails broken purely because of their aesthetic reasons.
In addition, a long time ago, some European countries (not only Germany) would impose corresponding taxes on dogs, but if they were a working dog, they could be exempted from paying this tax, so many people cut off their dogs' tails in order to avoid taxes.