This cartoon has been credited as being the inspiration for Chuck Jones' rakish style of humor. Prior to this, he had been making cartoons in the Walt Disney style that were softer, with more gentle overtones such as Sniffles the Mouse. With this cartoon he realized that he had a gift for slapstick comedy.
The title is a play on the term 'draft horse', which is a term used to describe a large working horse. Then, since this was released in the early part of World War II, it is also a play on The Draft, where men (in this case a horse, actually) were conscripted into the war effort for military service.
Although American troops were busy overseas, the home front was just as important. Scrap drives, victory gardens, munitions factory work and more were all part of the stateside war effort provided by everyday citizens.
The 4f draft horse is shown knitting for the troops at the end of the short. The sweater he holds up has a large V, for victory, on its front.
The horse is knitting a sweater for "bluejackets." A bluejacket is an enlisted man in the navy.