Hi Rich. It would seem that one could collect uncontaminated samples of amniotic fluid and detect bacteria from meconium passage. Also, examination of intestinal lymphocyte type and distribution would contribute to valuable insights, because there is continuous communication between the gut microbiome and lymphocytes in intestinal villi. My examination of late term abortion foals (I was an equine internist and researcher) would suggest a microbiologically “quiet” gut until birth. The horse placenta differs from the human placenta (more impermeable) so blanket extrapolations are not appropriate. The key, as you mention, is what happens during and shortly after birth. And then out into the world we go, exposed to everything under the sun.