This might seem a little obvious but it just occurred to me the other day. Bojack is a horse, horses used to be animals that were used all the time. But as time went on people used them less and less with the rise of automobiles. Eventually horses fell out of popular use. I could see this maybe being an analogy for Bojack, his rise to fame and then his fall into insignificance. What do you guys think, was it intentional?
Initially, it was just that the character designer loved horses. However, the show plays with the symbolism of horses, especially in regards to what they mean in regards to class. His father was working class, busting his ass to make not much, which reflects the legacy of horses being used for hard labor. His mother and her affluent background reflect the way the upper class views horses: as a status symbol. Beatrice making her debut is one of the most direct animal actions (for want of a better term) in the show. She is made to go out and make a spectacle of her extravegant dress and refined breeding, which has significance in both the horses of the affluent and the affluent themselves.
Bojack is both work horse and show pony.