The incident which landed owner Roslyn Condie in the court at Dumfries took place last September when the postman was delivering to an address in Mossdale near Castle Douglas and was bitten on the leg and left with a puncture wound.
Sentence had been deferred for six months when she appeared in court earlier this year and Sheriff Brian Mohan told Condie he would give the dog a chance and not order its destruction.
But on her latest appearance she was near to tears as she told the court that it had put to sleep a short time after her previous court appearance.
Condie, of Forrest View, Mossdale, had admitted being the owner of a dog which was dangerously out of control.
The court had heard that there was concern in the hamlet over the dog which had on occasion escaped from the garden of its home.
But it was stated on behalf of Condie that she had had Nipper since it was a puppy and described it as very affectionate, though she had kept it muzzled when taken out and the fences had been made escape proof.
She was fined £150.