No, I think to release all the other cows first you have to kill the Cow King then perform a purification ritural, that's presuming that you aren't cut to death by a herd of stampeding, halberd wielding Hell Bovine.
Scratchit: But he's a cripple!
Blackadder: He's not a cripple, Mrs Scratchit. Occasionally saying "Phew! My leg hurts!" when he remembers to wouldn't fool Baldrick!