The death of Keepara Lass is the third in South Australia this year. Overall, there have been 13 jumps-related racehorse deaths this year.
The latest death has added more fuel to calls by animal welfare groups for an end to jumps racing.
Racing Victoria suspended the sport in May following three deaths at the Warrnambool carnival. It later resumed jumps racing with safety changes, but promised a full review at the end of the season.