Sinkin' in the Bathtub (1930) was the first of the Looney Tunes series. It stars Bosko, a relatively unknown cartoon character later to be eclipsed by characters such as Porky, Daffy Duck, and Bugs Bunny.
This short is derivative of the contemporary Mickey Mouse series, which was at the height of its popularity in the early 1930s. Gags such as the cow shaking its utter in disgust or the goat which accompanies Bosko to his girlfriend's home are directly taken from Disney works going as far back as Oswald the Lucky Rabbit in the late silent era.
That being said, Sinkin' in the Bathtub is a cute but not essential short. A better introduction to Bosko would be Bosko's Picture Show (1933), which is funnier and very pre-code in its sensibilities.