Otho had proved only moderately successful on the race-track until 1767, the last year of his racing career, when he had several victories at Newmarket. This portrait with a mounted jockey, beside one of the rubbing-down houses at Newmarket, was presumably commissioned to celebrate these achievements.
Stubbs was often limited to painting standard horse portraits for proud owners. However, even in conventional subjects such as this, he raised the genre to a poetic level. His subtle atmospheric effects evoke the tension of racing, as the storm-clouds hint that the sunlight in which the horse and rider stand may be fitful.