A witness tells us 86-year-old Barker had been shooting when he went down. We're told Barker was conscious when help arrived.
Barker's rep tells us Bob had a reaction to a blood thinner medication which caused him to pass out -- and that he was taken by ambulance to Cedars-Sinai Medical Center. Bob was checked out, released, and he's back home now ... according to the rep.
Remember to have your pet spayed or neutered.
UPDATE: Barker's rep says he just spoke to Bob who now says he was dehydrated. Bob says he's going to take it easy at home for a while.