Paul McGear howling a loud "Woooo!" during a recording of "Oh Darling" at their studio. Listen to him sing: https://www.youtube.com/watch?v=NdGLEVKwHPU

Paul always seems to use "Woo!" along with all the other assorted barking noises before the guitar solo. Max goes for the growling "OWW!" as if someone has stepped on his tail. LOL