The Dhyana sloka in the Bhagvad Gita, says: Sarvo Upanishado gaavo: All the Upanishads are the cows: Dugdha Gopala Nandana: The one milks them is Krishna the cowherd boy: Partho Vatsaha: Partha or Arjuna is the calf (for whom the cow produces milk) Sudhir Bohkta: the wise are the enjoyers of it; Dugdham Gita Amritam Mahat the milk of immortality, the great nectar of immortality.