Emperor has a new spring in his step

When the super sire was found injured in his paddock of cows at Winchelsea, Victoria, his owners at Murdeduke Angus decided to try a knee reconstruction rather than shoot him.

"He's a wonderful animal and we've sold a lot of semen from him quite widely," said owner Bruce Wilson.

Dr James Vanner from the Geelong Veterinary Practice said they anaesthetised the bull in the paddock and diagnosed a ruptured cruciate ligament, probably sustained while "doing his job".

Emperor was sedated in the trailer and then walked to a secure room alongside the surgery, where he was anaesthetised by three Melbourne University vets before being intubated once he was on the ground and carried by two gantry cranes into surgery (pictured).

"Initially, we thought we could grow some cells to inject into the joint, but it was too unstable," Dr Vanner said.

"We opted for something known as the tightrope technique.

"We used 700-pound (about 307 kilograms) breaking-strain Marlin fishing line and two stainless steel plates either side of the joint.

"Holes were drilled through the bone and the fishing line was doubled through - so he's got double the strength of a 700lb line there."

Three surgeons - Dr Vanner, his colleague Dr Simon Pearce and Melbourne Uni's Dr Liz Walmsley - conducted the surgery, which cost about $5000.

While under anaesthetic, they removed 40 "adult" cartilage cells from the joint which Clone International's Dr Richard Fry will take back a few stages in development and grow to 20 million cartilage cells, which will then be injected into Emperor's stifle joint in about 10 days to help improve his recovery.