Old horse
A horse past its working years — earned rest, the dignity of a long service finished.
An old horse in a dream is the dream's image of a creature past its working years, kept on for the service it gave. The old horse is not productive in the way it once was, and it is not discarded. The dream brings the old horse when something in your life — a long-serving worker, an elder, a tool that has been with you for years — has reached the age of earned rest. An old horse in good pasture is the dream affirming that the rest is being honoured. An old horse worked to exhaustion past its time is the dream noting that the service is being extracted past what was promised, and the creature is being asked to give what it does not have.