At the very start of the game, you will obatain a puppy which will grow into a Dog in fall when you take care of him.
If your Dog has enough affection to you, you could actually join in the Dog Race.
Taking CareIf you want to get too hard taking care of your Puppy, picking him up and down would be alot more easier.
You will begin with a 10 Affection Points with the Dog. Some activities may decrease or increase the affection of your dog towards you.
The exceptional activity here is attacking your Dog with a tool. You can repeat doing this and the effect will not await for the next day.
Remember that the effect of the activity only works for a day so repeating the activity will render it useless.
|Activity||Affection Point per day|
|Picking him up and down||+2 Affection Points|
|Whistling at him and having a respond||+2 Affection Points|
|Ignoring him for a whole day||-1 Affection Point|
|Leaving him outside when the weather is not clear||-5 Affection Points|
|Attacking your Dog with a tool||-10 Affection Points|
At the very start of the game, you will see your Puppy going around. Since the affection of him towards to you is still only 10, the whistle will be useless this time. So, you need to find him and let him stay for your house until the whistle take effect.
DogYour puppy will grow into a Dog in fall.
Won will come by and sell you a ball, when you buy it, you can use it to your dog so it's intelligence will increase.
Your dog has a secret intelligence that will start out in 0 and it will never decrease. If you use the ball and throw it, your dog will pick it up for you. After that, your Dog's intelligence will increase by 3. 
The effect of the ball will only increase for a day so repeating it will be useless. The more the intelligence of the Dog, the more it will do good in the Dog Race.
Also, the minimum days of your dog to have a maximum affection to you is about 60 days. And for your Dog's intelligent, it will take by 85 days.
In the second year Spring, Barley will come by to your farm to visit your Dog and will take it to his Ranch. After some days, he will return your Dog and after some weeks, Hana will give birth to two puppies which you will decide if you will give it to Stu or Harris.