Lord's pet animals

Nanda Maharaja had 900,000 cows. Visvanatha Cakravarti gives this description of the 

cows  of Vrindavana. Krishna knew every cow by name. If any cow was missing Krishna  

immediately chase after the missing cow and call her by name. The cows were divided into

 herds by color, either black, white, red, or yellow. In each color there were 25 further 

divisions making a total of 100 herds. There were also eight herds of cows that were spotted 

or speckled or had heads shaped like a mridanga or that had tilak marks on their foreheads.

 There was a total of 108 different herds of cows. Each of the 108 herds had a herd leader.

"Thus when Krishna calls out, 'Hey Dhavali' (the name of a white cow) a whole group of white

 cows comes forward, and when Krishna calls 'Hamsi, Candani, Ganga, Mukta' and so on, the

 

twenty-four other groups of white cows come. The reddish cows are called 'Aruni, Kunkuma,

 Sarasvati, etc., the blackish ones 'Shyamala, Dhumala, Yamuna, etc., and the yellowish ones

 are Pita, Pingala, Haritaki, etc. (Srimad Bhagavatam 10.35.19 purport)



"As described in the Brahma Samhita (surabhi apbipalayantam), Lord Krishna on His planet,

 Goloka Vrindavana, engages in tending the surabhi cows. These cows are the Lord's pet 

animals." (Srimad Bhagavatam 8.8.2 purport)