Based on

Movies like Milk and Money (1936)

Porky's father is going to lose his farm. Porky goes to town with his horse and works a milk route, with a warning that if he breaks a bottle he's fired. As he's delivering, cats follow along behind draining the bottles. Meanwhile, Hank Horsefly follows them into town. He stings Dobbin, who crashes and breaks many bottles. They happen upon a horse race and accidentally enter; the horse is merely plodding along until it gets stung again.