"In the Tenth Canto, 21st Chapter, 13th verse of Śrīmad-Bhāgavatam there is an appreciation by the gopīs of the inertia of the cows in Vṛndāvana. The gopīs saw that the cows were hearing the sweet songs vibrated by Kṛṣṇa's flute and were appearing to be drinking the nectar of these transcendental sounds. The calves were stunned, and they forgot to drink the milk from the milk bags. Their eyes seemed to be embracing Kṛṣṇa, and there were tears in their eyes." NOD 30
http://prabhupadabooks.com/nod/30
