I want to buy this cow.

Good dairy deal only if the milk is real and the udder is clean. Before paying, milk her in your presence, do a CMT test on all four quarters, and ask the lactation month. If she is in month seven or eight, that eight liters can fall fast. Check age, body condition, and vaccination papers too. For a purchase above fifty thousand, take a Pashumitra or vet. If you want, I can help you judge whether this cow is worth the price.