Horlicks is the classic sleepytime drink, they even advertise it as a bedtime drink. It's warm, milky and malty. When my dad was in hospital recovering from a heart attack, all he wanted was a nice cup of Horlicks. We decided he was regressing to his childhood a bit.
What show were you watching? It's not something you would ever normally give to a dog, were they trying to get the dog to sleep?