As they had done with other live action TV series, Filmation originally intended to produce an animated adaptation of M*A*S*H. However, M*A*S*H producers refused to authorize such an adaptation.
Ironically, the show debuted when two characters from M*A*S*H parodied on the show (Blake/Flake, Trapper/Trooper) had just been replaced.
"M-U-S-H" stood for Mangy Unwanted Shabby Heroes.
M-U-S-H was a series of 6 minute long cartoon shorts that were part of Uncle Croc's Block (1975). Most of the characters were based on characters from M*A*S*H (1972): Bullseye, Trooper Yoe, Cold Lips, Major Hank Sideburns, Colonel Flake and Sonar. It was never made clear exactly what the dogs were doing in Upper Sibonia; although rifles were shown occasionally, the dogs were never seen fighting. Nor was M-U-S-H a hospital as none of the main characters were doctors or nurses. In the opening credits, the dogs were referred to as peace officers.