Buying horses...

Juan and Jose were shopping for horses. When they'd each found the horse they wanted, they were in a quandary.
"How will we tell which horse is yours and which is mine?" asked Jose.
"I know. You crop your horse's ears and I'll leave mine as they are," answered Juan.
"No, that would hurt the horse."
"Okay. I'll cut my horse's tail and you keep your horse's tail long."
"Nooooo! Horses need their tails long to brush flies off."
"I know. Branding! I'll put a big X on the rear of my horse. And you put a big Y on yours."
"No, no. My horse is too beautiful to mark up like that."
"I've got it," said Jose. "You take the black one. I'll take the white one."