Bossy is a cow that is milked once a year. That milk is made into cottage cheese.
In the episode "Dr. Three-Brains", Dr. Two-Brains' original plan was to steal the cottage cheese; Glen Furlblam, trying to outstand Dr. Two-Brains, tries to steal both Bossy and the cottage cheese.
Glen tries to ride Bossy as an escape, but fails. When Glen tries to use the black-out ray, Bossy hits him with her tail, causing Glen to fall off.