Bet ya didn't know.......

this is kinda like expressions...."whats got your goat?", or where does the word **** come from.

I discovered while doing research on my fainting goat(long story) that horse trainers kept goats as companions for race horses. If an less than honest opponent wanted to cause the favored horse stress they would steal the goat. Hence "whats got your goat" or "who's got your goat". The horse would be stressed from missing its companion and not perform well. Of course this could all be bullshit but it sounded logical to me. :)