Every writer needs a good editor

I got about three pages into the novel I'm currently reading (Moon Pies and Movie Stars by Amy Wallen) before I hit a major blooper:  black and white Jersey cows.  Granted, the book is fiction, but that doesn't excuse getting your context wrong. So if you're going to name a breed, for Calliope's sake, don't screw it up by making it the wrong color!  If you don't know something, don't try to