It is well enunciated in Tamil Saivite Literature by the popular Thevaram Poem penned by Saint Thirugnanasambandar where he starts with praying for the welfare of Vedic brahmins and cows.
வாழ்க அந்தணர் வானவர் ஆனினம்
வீழ்க தண்புனல் வேந்தனும் ஓங்குக
ஆழ்க தீயதெல் லாம்அரன் நாமமே
சூழ்க வையக முந்துயர் தீர்கவே
The same is repeated in numerous Sanskrit texts and murdering a cow is listed as one of the most nonredeemable sins. On the contrary nurturing cows can clear us of worst of sins. What better espousal of this cause can we find other than in the words of Kanchi Sankaracharya maha swamigal
https://www.kamakoti.org/tamil/3dk40.htm
https://www.kamakoti.org/kamakoti/stotra/acharyascall/bookview.php?chapnum=56
See also :