A man is certainly most miserable who takes care of a cow that gives no milk.
The example of the milkless cow is significant. A gentleman never kills a cow, and therefore when a cow becomes sterile and no longer gives milk, one must engage in the laborious task of protecting her, since no one will purchase a useless cow. For some time, the greedy owner of a sterile cow may continue thinking, “I have already invested so much money in taking care of this cow, and certainly in the near future she will again become pregnant and give milk.” But when this hope is proven futile, he becomes neglectful and indifferent to the health and safety of the animal. Because of such sinful neglect, he must suffer in the next life, after having already suffered because of the sterile cow in the present life. The example of milkless cow is given to illustrate the uselessness of laboriously studying Vedic knowledge that does not glorify the Supreme Personality of Godhead. Śrīla Jīva Gosvāmī comments that the spiritual vibration of the Vedas is meant to bring one to the lotus feet of the Supreme Lord, Kṛṣṇa. Many processes for achieving the Supreme Truth are recommended in the Upaniṣads and other Vedic literatures, but because of their innumerable and seemingly contradictory explanations, commentaries and injunctions, one cannot achieve the Absolute Truth, the Personality of Godhead, merely by reading such literature. If, however, one understands Śrī Kṛṣṇa to be the ultimate cause of all causes and reads the Upaniṣads and other Vedic literature as glorification of the Supreme Lord, then one can actually become fixed at the Lord’s lotus feet. For example, His Divine Grace Śrīla Prabhupāda translated and commented upon Śrī Īśopaniṣad in such a way that it brings the reader closer to the Supreme Personality of Godhead. Undoubtedly, the lotus feet of Lord Kṛṣṇa are the only reliable boat by which to cross the turbulent ocean of material existence. Even Lord Brahmā has stated in the Tenth Canto of Śrīmad-Bhāgavatam that if one gives up the auspicious path of bhakti and takes to the fruitless labor of Vedic speculation, one is just like a fool who beats empty husks in hopes of getting rice. Śrīla Jīva Gosvāmī recommends that one completely ignore dry Vedic speculation because it does not bring one to the point of devotional service to the Absolute Truth, Lord Śrī Kṛṣṇa.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Eleventh Canto, Chapter 11 – Text 19.
