When my Great Danes got older (every one of them between 10-13 years old) slept on occassion they would lose their bowl just a bit and I would find small amounts of poop dried up on their blankets. It is normal because as they get older they close their full control just a little bit while they are asleep. Not always just sometimes but as they got older and closer to rainbow bridge it got much worse. We released Beast Dog to rainbow bridge in 2013 and she was still having some great days but she would lose her bowls just while she was walking. We knew it was time. Nothing to worry about for now but just know as they get older the reoccurence does happen more regularly.
By the way, I rescued a Great Dane last night, his name is Ralph. He is 2 years old, gets along great with the girls, is two foot taller than the girls (lol) but bonded with our daughter Kristana instantly. No aggression issues, just neglect from having to fight for his life with an Alpha male. He is under weight by about 25 pounds but he will come around. He gets his shots tomorrow morning and neutered on Monday. I don't think Kristana will be giving him up; he has already claimed his spot in her bedroom to sleep, Ruby sleeps with her, and Amber likes the livingroom. He fits in great with our private zoo.

He is also the same color as the cows

Good stuff!!