The Cow lives in the Forest and Swamp biomes.
It gives you Beef and Leather when killed. You can also obtain Milk with the Bucket.
You can use Fences and Gates to create a cow pen. Buy the Rope from the Farmer or the Traveling Merchant and feed Wheat to the Cow to lead the animal to the pen.
The Cow can be mated using Wheat. You need at least 2 cows to start breeding them. You can give them Wheat by hand or through the Feeding Trough.