I'd guess you shot low. Sounds like you grazed his brisket and/or leg. White hair there? Check. Brown hair there? Check. Meat there? Check. Fat/grease there? Check. If you hit him high, and had hair and meat but no decent blood, you wouldn't have likely found the first drop of blood, even if he stood at a spot for several minutes. They don't have white hair on their backs either.