Although Pṛṣadhra had committed the sin unknowingly, his family priest, Vasiṣṭha, cursed him, saying, “In your next life you shall not be able to become a kṣatriya. Instead, you shall take birth as a śūdra because of killing the cow.”
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तं शशाप कुलाचार्यः कृतागसमकामतः । न क्षत्रबन्धुः शूद्रस्त्वं कर्मणा भवितामुना
taṃ śaśāpa kulācāryaḥ kṛtāgasamakāmataḥ | na kṣatrabandhuḥ śūdrastvaṃ karmaṇā bhavitāmunā
SB 9.2.9