3 1/2 week old puppy vomiting

Question
We have a liter of 5 pekingese puppies. They are 23 days old. All playful and nursing well. One of them today sat up and did that gagging thing and looked as if he was about to vomit. Nothing came out though. He did it several more times within 30 minutes, but nothing came out. Also, when I picked him up he had gas. Not to be funny, but it just smelled like regular dog "gas". Then he laid down and went to sleep. They aren't on any food yet, just nursing. Last week I did give them some of the newborn mother's replacement milk. They didn't drink very much of it though. I looked at his rectum and it's not dirty (from diarrhea). Although he could have and the mother just licked it clean, not sure.  I'm just very worried about him. Mother has all shots done and is on Heartworm Preventative. I'm just praying that it's not a disease like parvo. We have other dogs. They have not been around the puppies or even in the room and they are all UTD on shots too and healthy. Please help! Thanks.

Answer
Hi. He simply could've gotten something in his throat he was trying to hack up. Vomiting at this age could meana  few different things. If he continues this, I would take him straight in ot the vet. I really don't think it's parvo, could be something simple. Maybe a trip to the vet for a stool sample may be in order though. Good luck.