D.B.
When my twins were born we left blankets they had slept in on the floor for our cats and dogs to investigate and to get accustom to their scent. Also we place the twins in the car seat carriers, set them on the floor, sat next to them and then let the animals investigate them. Thankfully we did not have any issues, but some pets are more "sensitive" than others and yours may just need a little more time or some extra attention (I know that can be hard w/ a newborn)
Best of luck!
Also we put a screen door on their bedroom, so the animals could not get in but we could still hear and check on them w/out having to open the door.