Posting under the username Winelover93, she wrote: "My 8 month old loves dog food more than his baby food! I let him crawl around the flat I find him next to the dog's bowl scoffing his face.
"I take it out his mouth bring him into the living room then I realise he has more curled up tight in his hands."
One wrote: "Take the dog food off the floor. Our dog is fed once a day whilst the baby is safely in her high chair".
Another added: "That is revolting. Jesus. Feed the dog separately. In the bathroom or wherever you can with a door closed between the baby and the dog."
Meanwhile, one mother suggested it was dangerous to "free feed" the dog with her baby around, writing: "You're also running the risk of the dog starting to resource guard it's (sic) food - which is absolutely not a safe situation for a baby to be in".
Responding to the criticism, the baby's mother later explained that she left dog food out as she has a chihuahua and "he doesn't eat all at once", but said she would take on board the advice.
One Mumsnet user did later back up the baby's mother, saying she had experienced a similar problem with her child with cat biscuits.