You'll find the cow barn between the horse barn and your fodder silo. If you are playing as the girl main character, you'll start out with one cow in your barn. If you're playing as the boy main character then you won't start with any animals.

You will need at least 6 patches of grass growing in the cow pasture behind the barn. Once you have that, you can go to the Farmer's Union and buy a cow. Cows cost 5000 G each and you can choose between a male or female cow. Right after you buy it the cow will be in your barn. Don't forget to feed it before you go to bed!

Cows grow in three stages: calf, young cow, and adult cow. You can only sell adult cows back to the Farmer's Union for 5000 G. It doesn't make much sense to buy a cow, raise it until it's an adult, then sell it back for the same price you bought it for. Since breeding cows to produce more cows doesn't cost you any money, you can sell those ones instead. There are 4 different cow colors. There's brown with big spots, brown with small spots, black with big spots, and black with small spots.

Every day (when not unhappy or sick) adult cows will produce milk. The affection level of the cow determines how much milk it will give. Cows with 0 to 3 hearts will produce small milk, 4 to 7 hearts will produce medium milk, and 8 to 10 hearts will produce large milk. There is no way to produce golden milk like in the first Harvest Moon game for Gameboy.

Only the girl can use the Milker that is needed to collect the milk. To use the Milker equip it, walk up to one of your cows, and then press the A Button. The milk will pop up over your head when you've finished. If you're playing as the boy then have your girl partner do the milking by selecting "M-E-W" or "Anything".

Besides milk, you can also ship butter and cheese. After you have shipped enough milk, the machines will appear in Lucus' Tool Shop. When you buy the machines they'll appear next to the fodder bin when you first enter the cow barn. To use them just milk a cow, carry the milk to the machine, then press the A Button to toss the milk onto the machine. You'll then be carrying butter or cheese, and you can press the B Button to put it in your rucksack. Any size milk will create cheese and butter.

If you're playing the boy version then you can buy the butter and cheese books from Lyla's Book Shop so your girl partner can make them without having to buy the machines. Your partner will randomly make the butter and cheese on her own.

Like horses, you can enter cows into a contest at the Farmer's Union. Not a cow race of course, but a judging contest. Go to the Farmer's Union and select the cow graphic in the lower right corner. You'll be asked if you want to register your cow. The better your cow ranks, the more widespread your fame will be for being such a good farmer. It's a good idea to only register cows that have 10 hearts. Only adult cows can be entered so no calfs, young cows, or pregnant cows. You can only register a cow once too. Unlike the horse race, you do get your cow back.