horse: I don't know why, but I never seem to win the close races
He doesn’t win races because the other horses necks are longer and thus they cross the finish line. It isn’t a joke based on “neck and neck” or “wins by a nose” It’s simply the idea that a longer horse (in this case because he has a longer neck) will win races. It’s not about a particular idiom.
July 17, 2015