Horse trainers, racing-industry officials and vets expressed concerns Wednesday with Kentucky’s proposed out-of-competition drug-testing rule at a second public hearing at Keeneland. At the public meeting Tuesday at Churchill Downs, attendees asked whether the rule somehow can be temporarily implemented to cover the Breeders’ Cup in November and then be rewritten to more fully address concerns. The Kentucky Horse Racing Commission wants to have an emergency regulation to allow testing virtually any time, anywhere for illegal blood-doping agents, growth hormones and nerve-blocking venoms. But questions have been raised. For instance, David Switzer, executive director of the Kentucky