This morning I found the end of my dog's collar on the floor and could not find the rest so I suspect that he ate it. The part he ate contained no metal but I'm very worried!! So I fed him this morning, got home from work around 3 ish, he seems fine to me- if there is pain or anything I wouldn't know it. He was playful and I took him for a short walk. I see no abnormalities with him but I will continue to check his poop and monitor him.. Is this serious??