Have Angela Deth or Chisel in your party, and use the Brute Force skill on the cows at the infected farm, Canyon Of The Titan, or in Damonta (after saving the herd). You can find up to ten cows at the agricultural center. However, they will be attacked by rabbits. If quickly launch an attack against the rabbits, you can save five cows. To see the cows, you must first help the agricultural center.