Paula Wilson, 15, said that her daughter Ashley had been lying in a bouncing chair at her feet when their English bull terrier - a breed not covered by the Dangerous Dogs Act - grabbed the baby by the head, inflicting terrible injuries.
She was having an evening meal on 22 December in the kitchen-diner of their home in Penwortham, Preston at the time of the attack.
"Ashley was playing around in the chair. . . She had a rattle with ducks on over the chair and Dodger [the dog] went underneath it and pulled them off and grabbed hold of her," she said.
Paula's mother, Valerie Randolph, said she was in the next room when she heard Paula telling the dog to get down.
"I thought he was jumping up on the table," said Mrs Randolph. "But seconds after that we heard a growl and a noise and Paula shouted `Mum, the dog has got the baby'.
"The dog was over the top of the baby chair and had hold of Ashley by the head. Paula had her hands over her face and I put myself between Paula and the baby. I was afraid it would be distressing for her," she added.
"I had to get the dog off by just trying to command him to let go and pulling his mouth open without any tugging."
She received wounds to her arms as she pulled the dog away.
Two police officers were called to the house just after 9pm. They took the child to the Royal Preston Hospital without waiting for an ambulance. She died two hours later.
Dr Edmund Tapp, a consultant pathologist, told the inquest in Preston that the cause of Ashley's death was brain injuries with cuts and bruises. She was the fourth child in five years to die after being savaged by dogs.
The family had owned the dog for two and a half years and when the baby was brought home there were no signs of any problems.
Detective Inspector Graham Bamber, who had led the investigation, told the coroner: "With the baby they clearly exercised caution, but the dog has betrayed that trust. For three and a half weeks it had done nothing wrong, but in a 30-second moment in time this tragedy happened."
Recording a verdict of accidental death the coroner, Howard McCann, said that Ashley's death was "one of the most tragic I have ever had to deal with".
He added: "I don't pretend to understand the psychology of dogs but here we have a situation where the dog has been around for some time.
"The lesson is to be aware of the problems of dogs with young babies. As far as this family were concerned they were aware. It just goes to show that on one occasion a dog such as this can turn nasty and attack a child."
The dog was destroyed in accordance with the wishes of the family. Lancashire Police said they had received about 20 calls offering the animal a home.Reuse content