There are three classes of animals in Harvest Moon 64: pets, livestock, and wild animals. Pets and infant livestock can't get sick, hurt, and are basically immune to everything. You can't grow new grass in winter, but if you had fully grown grazing grass in Fall, cows and sheep can reach it through the snow.
Pets[edit]
There are two pets available: a dog and a horse.
The dog comes with the farm, and can participate in the Dog Race every year on Winter 19. You must visit the Green Ranch during the first Spring to get a horse, but it can participate in any of the Fall or Spring horse races. Once it matures, you can use your horse as a portable shipping crate.
Whistling your dog 
or your horse 
increases their affection by +1, once per day, regardless of how far away you are. Picking up your dog, talking to your horse, and riding your horse each increases their affection by +1, once per day. Rick sells a brush that can increase a horse's affection by +2, once per day. The horse's affection decreases by -1 every time you sleep. The dog either gains +1 or loses -1 affection, depending on if there was food in the bowl when you went to sleep the night before.
Livestock[edit]
Livestock is bought from Ann's father at Green Ranch. The coop holds up to six chickens and the barn holds a total of eight combined cows and sheep.
Chicken[edit]
- Buy: 1500G
- Sell: 500G
Chickens will give one egg per day if fed the day before and not still sick or starving from prior conditions. You can sell each egg for 50G or put it in the incubator for three days to hatch a new chick. You can sell a sick chicken for the same price as a normal one. Unless it is raining, chickens can find food outside and don't have to be fed.
If there are any chickens left outside during a typhoon, there is a 100% chance it won't be there in the morning. When an animal dies, there is a small funeral cutscene in the small graveyard of West Flowerbud Village. Being friends with the Harvest Sprites doesn't change whether or not they feed your animals during bad weather.
Cow[edit]
- Buy: 6000G
- Sell: 6500G + (500G for M; 1000G for L; 2000G for Gold)
Cows can be milked once per day, and will give a different amount of milk depending on their affection level. You can only use a milker once per day, but you can use a bottle as many times as you want to extract milk. A cow will permanently give gold milk if it wins a Cow Festival (Fall 4):
| Affection | Milk Size | Sell Price |
|---|---|---|
| 0 - 150 | Small | 100G |
| 151 - 220 | Medium | 150G |
| 221 - 255 | Large | 300G |
| Win Cow Festival | Gold | 500G |
Cows have five condition types: 00 is Normal. 01 is Happy. 02 is Mad. 03 is Sick. 04 is Dead. When a cow reached "Happy" mood, it will be immune to any other condition changes for three days. A cow that is mad and is unfed will remain mad and never die of starvation. Sick cows and sheep will not heal on their own. You have to buy some medicine from the Green Ranch for 1000G each. Otherwise, cows and sheep remain sick until they die on the seventh day.
Normally, hitting an animal with a tool causes a severe affection loss. However, if a cow is mad or sick when hit with a tool, it gains +20 affection per swing. Hitting a sick cow can change the cow's status to mad, curing its sickness.
A cow will win the Cow Festival if it is at 240 affection or higher and you have placed at least 60 milks in a shipping bin before entering the Green Ranch screen. Actions can be performed once per day to increase the cow's affection:<
| -- | Happy (01) | Normal (00) | Mad / Sick (02/03) |
|---|---|---|---|
| Talk | +2 Aff | +1 Aff | +0 Aff |
| Brush | +4 Aff | +2 Aff | +1 Aff |
| Milk | +2 Aff | +1 Aff | +0 Aff |
Sheep[edit]
- Buy: 4000G
- Sell: 4200G + (400G for 100-199 aff; 1000G for 200-255 aff)
Sheep can be sheared and the wool can be sold. You can sell sheep back to the Green Ranch, but not if it is sheared. Wool grows back seven days after being clipped off.
- Regular Wool - 900G
- High-quality Wool - 1,800G
Sheep have three condition types: 00 is Normal. 03 is Sick. 04 is Dead.
| -- | Normal (00) | Mad / Sick (02/03) |
|---|---|---|
| Talk | +1 Aff | +0 Aff |
| Brush | +2 Aff | +1 Aff |
| Shear | +2 Aff | +1 Aff |
Wild Animals[edit]
Wild animals are mostly used to create atmosphere. There are different wild animals for each season, such as snakes and monkeys in summer and butterflies in spring. Wild animals can be picked up and shown to people, but have no other real purpose.