Kristi,
We don't give our newborns probios unless there's a medical problem. And the vet advises with that.
We give a child's enema to the foal if it hasn't pooped about an hour after first nursing. We use the Fleet infant and administer the full amount VERY gently. HOWEVER, our favorite enema for a newborn is "homemade", but using the Fleet applicator. Our homemade consists of -- filling half of the bottle with mineral oil, half with warm water, and a DROP of liquid soap. We were given this "recipe" by a vet years ago.
Just for the record, their "first poop" is often encouraged by taking in colostrum.
We don't worm a new foal, but we do worm the dam immediately after birth with Ivermectin. The new mother gets the wormer, some banamine, and a dish of grain as soon as she's back on her feet. The wormer gets passed onto the foal through the milk. The foal is then given a first gentle wormer (either Panacur or Safeguard) when it's about 2 months old.
Just what we do.......