Animal rights activists have renewed calls for a ban on jumps racing after a horse was euthanised in Adelaide.

Trenchtown suffered ligament damage in a race at Morphettville on Saturday, said the Coalition for the Protection of Racehorses.

The horse's death came one month after it fell during a steeplechase at Bendigo.

"There are serious questions to be answered as to why Trenchtown was allowed to race after a fall when not cleared by a vet, and then a month later has been killed," said campaign director Elio Celotto in a statement.

The organisation says Trenchtown is the fourth horse to die in a jumps race so far this year.

In February, Thoroughbred Racing SA decided to reduce the number of hurdle races held during 2015, effectively overruling the South Australian Jockey Club's call for an end to jumps racing in Adelaide.

The RSPCA and SA Racing Minister Leon Bignell also support a ban.

Victoria is the only other state that still allows jump racing.