Well I'm assuming its bad for dogs because I've never heard of anyone giving dogs milk. I know that with my mom's cats they get diahrea.
Anyhoo my nephew was over the other day and left his glass of milk on the floor when he went to go rinse his plate off. We came back into the living room to see Rory had her nose in his glass which is REALLY strange. She is the best about not begging and I can leave food sitting on the coffee table with her right there and she wont even attempt to get at it. She is really good about this because I never feed her human AT ALL. If anyhting she is wary when I offer her treats but with the milk she was freakin out!
I went to pour it in the sink, she put her paws on the counter and I've never seen her do that before, she then proceeded to go around sniffing everyone's glass and actually begging. I wasnt to happy about this. After every dinner we give her one of her regular treats for being good and not begging and she wanted nothing to do with it. That is a first, she wanted milk really really bad.
I checked her stools the next morning, they were fine and last night she was begging for milk while we ate.
I dont plan on giving her milk even if you all tell its not bad but I know a lot of you give vanilla ice cream as treats. She has had it maybe twice but didnt go crazy for it like milk