Cropping of the ears made sense when the dogs primary purpose will make those ears susceptible to injury. Like in the case of the Great Dane. Originally War Dogs and then adapted for hunting larger size game, like wild boars. The boars tusks would catch on the ears and that is why they started cropping the ears on Great Danes.
I find it difficult to believe that some people still try to make the argument that it is in the dogs best interest. I find that hard to believe as labs have just as many problems with their ears and I have never seen a lab with cropped ears.
Hans
www.lucysdoghouse.net