kasmān na bhavatā gaur ityetasya nāgaurityeṣo 'pohalakṣaṇaḥ śabdārtha ucyata iti vākyārthaḥ /
Why do you not state that the meaning of the word 'gaur' [cow] is characterized by the exclusion [apoha] in the form of 'not non-cow'?