To in 20. Century in Germany usually living animals were sold at butchers for slaughtering. The butchers were forced to drive the bought cattle of the market - or partly also directly of the farmers - to their slaughterhouse. For this purpose the butchers held themselves large, strong, courageous dogs, which driving the battle cattle took over. Beyond that the dogs were by their durable and strong figure also in a the position small load trucks, the butcher trucks, to pull.
Also it was usually, if the butcher with relatively much money went to the market to be attached in order to buy cattle, the purse its dog to collar in order to make sure in such a way that nobody stole the money.
An example of one with the butchers at that time very popular dog race are the Rottweiler, which is brought also again and again since this time with the term "butcher dog" in connection.
General it is to be said however that accurately defined "dog races" as such a product late 19. and 20 Jhd. are. Depending upon task were size and a character of a dog importantly; whether it had a certain appearance, was completely unimportant.