"Porky's Poppa" contains one of the first ever references to ACME in a Warner Brothers cartoon. In this case, Porky's Poppa orders an ACME mechanical cow via telephone. And true of ACME products to come, said robot causes considerable mayhem.
Bessie's boyfriend (shown in a pin up) is named Bull Bontana, a play on professional wrestler Bull Montana.
Although foot-and-mouth disease is a serious malady, it's made light of here by showing Bessie with her hoof in her mouth (a play on a popular saying).
The loopy black duck looks like a very early version of Daffy Duck.
The vanishing cream sight gag was popular with animators through the years. However, vanishing cream didn't bestow invisibility, it only 'vanished' into the skin (by absorption) while cold cream was meant to retain its texture and remain on the skin surface.