Reports confirm that the dog was owned by the mother's boyfriend who is currently in prison. The dog was kept in a cage that was too small for it, and not exercised. It appears that the child's cries acted as a trigger to the dog who attacked the child, with fatal results.
Although this is a deplorable situation, we must be wary of 'revenge' sentencing, which is not how the law works.
There is no doubt that this was a lethal combination of circumstances - an inadequate mother and grandmother left saddled with a brutal dog in which they had no interest, and the lack of intelligence in realising that a dangerous dog and a small child is not a good combination.
But, dispassionately, it has to be seen in the context that no malice was intended, and these women must live with the guilt of this baby's death for the rest of their lives.
So I believe the law has acted appropriately, even though I entirely side with the outrage of people who believe that something more should have been done, but that is in order to assuage our grief and anger, and that is not how the law is applied.