There has been no improvement in the condition of Black Caviar's little brother who is suffering from the life-threatening hoof disease laminitis.

Affectionately known as Jimmy by his owners BC3 Thoroughbreds who paid an Australian record $5 million at the Easter yearling sale, the colt remains at the Werribee Veterinary Clinic.

A half-brother to champion Black Caviar, Jimmy was originally treated for a spider bite but a reaction to the antibiotics brought on laminitis in his two front feet.

BC3 issued an update on Twitter on Friday, thanking people for the messages of support.

"We are overwhelmed with the response," BC3 said.

"Jimmy was radiographed today and there is no improvement in his condition.

"He remains stable and comfortable, surrounded by the best veterinary team at Werribee.

"We will now play the waiting game over the weekend and do not expect to have any further news.

"For now our focus is on him and giving him every chance."

Although the chances of the colt being able to race are limited, if he can be saved is a valuable breeding proposition.

He is by multiple Australian champion sire Redoute's Choice out of Helsinge who, in addition to the unbeaten Black Caviar, has also produced another multiple Group One winner, All Too Hard.

By Casino Prince, All Too Hard was retired to Vinery Stud earlier this year.