The dogs cold nose is an old joke,probably set to music by some smart arse writer with more skill than I have.

Noahs Ark developed a leak and the dog stopped it with his nose until it got too big so Mrs Noah stopped it with her shoulder until it got too big, then Noah sat on the hole until they got some patching on the outside,which explains why a dog has a cold nose a woman will give you the cold shoulder and a man always stands with his back to the fire.