Dog and child are inseparable friends. Animals are not only the same species, but one species can respond to the emergence of a baby in the house quite differently. It all depends on how stable the animal psyche, how it’s curious and driven, he doesn’t have a stresses, as perceives any new thing.
Perhaps the pet will show the usual curiosity: “What is it?” Then he will get acquainted with the new object, sniff and lose interest. This is the most welcome reaction. Dogs in General are more emotional than cats. Some are afraid of the baby.
Some show active interest, trying to lick the baby, quickly respond to the groaning, weeping, worried, trying to participate. With a cat can be a problem, even if it behaves inappropriately: attacking feet, shows aggression, etc.