Signal is how I keep in touch in Ukraine. Good for Signal

I was taught that same thing. Mammals are born with a "sterile" intestinal tract that will gather bacteria from the world around it shortly after birth. Can't claim any knowledge about baby guts, but with puppies, we give them a dose of probiotics then put them on their dam for first milk. We know bad stuff gets in there but we want our good stuff to get their first and start populating the tract. Interesting stuff on this sub.