I just wanted to mention the fact that you regularly give your dog milk ... unfortunately, milk is not good for
dogs, so I would stop this straight away.
Dogs are commonly lactose intolerant, for one thing, and while humans have specific enzymes to break down lactose (apart from those humans that are themselves lactose intolerant), dogs do not have enough of these enzymes, and the lactose often therefore causes diarrhea and/or digestive upset.