कल्पान्तरे विश्वासटिप्पन्यः

It came to be a prime duty of the king to protect cows from slaughter in his domain.
(गोब्राह्मणेभ्यश् शुभमस्तु नित्यम् …)
Shivaji cut off hands of cow killers, gangAdevI decries wanton cow slaughter by the mlecCha-s.

keraLa

Duarte Barbosa, a 16th century Portuguese writer : “The King then asks him if he will maintain the customs and rules of the other Nayres (Nairs), and he and his kinsmen respond ‘ Yes.’ Then the King commands him to gird on his right side a sword with a red sheath, and when it is girt on he causes him to approach near to himself and la, his right hand on his head, saying therewith certain words which none may hear, seemingly a prayer, and then embraces him saying ‘ Paje Gubrantarca, that is to say ‘ Protect cows and Bramenes (Brahmins)” [GB]
A similar oath was made by Samuthiris or Zamorins, the Nair kings of Calicut before their royal coronation “At Yagneswaram he is met by Vemaneheri Namputiri, a descendant of Melattur Agnihotri. The Eralped (Zamorin) gives him an ola (text), promising to protect Brahmins, temples and cows.” [Ar]
It is interesting to note that Aithihyamala, a 19th century work detailing many folklore and legends of Kerala also records an incident in which the famous 18th century Raja of Cochin, Rama Varma Shaktan Thampuran executed a Muslim who had killed a cow. The Raja also refused to observe Shivaratri vrata since the Muslim had killed the cow on that day.