Staff at Ranch Hand Rescue feared they would have to put down three-legged Midnite when he first arrived at the sanctuary for farm animals in North Texas.

Law enforcement officers had rescued the miniature horse, born minus a hoof and coffin bone in his right rear leg, from a neglectful owner before handing him over to the charity rescue centre.

However before Midnite could be put to sleep, Bob Williams, who runs the sanctuary, had a brainwave whilst watching televsion.

"One night we were watching a news story and what happened was ... we saw they were building prosthetics for humans, and we thought if it can be done for humans can it be done for a horse?," said Mr Williams.

Mr Williams asked a local company that specialises in creating artificial limbs for humans about the prospect of making a fourth hoof for Midnite, and the firm duly undertook the challenge.

In the beginning all involved in the project simply hoped the new limb would save Midnite's life by allowing him to walk.

However, after his second fitting, that hope proved to be rather modest as Midnite took off at a canter, the prosthetic limb an astounding success.