स य एवमेता रेवत्यः पशुषु प्रोता वेद पशुमान्भवति सर्वमायुरेति ज्योग्जीवति महान्प्रजया पशुभिर्भवति महान्कीर्त्या पशून्न निन्देत्तद्व्रतम् ॥ २.१८.२ ॥
In plain words
He who knows the Revatī verses thus woven upon animals comes to be rich in animals, reaches his full span of life, lives long, becomes great in offspring and cattle, great in renown. Let him not speak ill of animals: that is the vow.
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
पशून् न निन्देत्, तद्व्रतम् ॥
In plain words
One must never speak ill of cattle; that is the observance.
Close to the Sanskrit
He should not criticize cattle, that is the vow.