Anybody who finds it easy to make money on the horses is probably in the dog food business.

Jones’s quip plays on the long-standing belief that betting on horse races is a near-certain way to lose money for most people. If someone claims it’s “easy” to profit at the track, the joke suggests their gains are illusory—or that they are profiting indirectly from others’ losses. The punchline, “in the dog food business,” implies they are so unsuccessful at horse betting that the only reliable outcome is ending up with “dog food” (a comic euphemism for a cheap, humiliating fallback). More broadly, it satirizes get-rich-easy claims and warns that apparent effortless profit often masks risk, self-deception, or a business model built on others’ gullibility.