SB 10.24.21
krsi-vanijya-go-raksa
kusidam turyam ucyate
varta catur-vidha tatra
vayam go-vrttayo ’nisam
Translation:
The occupational duties of the vaisya are conceived in four divisions: farming, commerce, cow protection and moneylending. Out of these, we as a community are always engaged in cow protection.