The dog, known as Baby Girl, was found tied to a fire hydrant and rescued by a charity last week. The animal rescue center did not share the details of the note, but it did say that the dog has diabetes mellitus, also known as canine diabetes, which can lead to high blood sugar.
It was discovered on a residential street in Green Bay, Wisconsin.
The Wisconsin Humane Society suspects its previous owner had struggled to provide the care and attention he needed, the Daily Mirror reports.
The girl requires daily glucose monitoring, a restricted diet and insulin injections at home due to her health problems.
A spokesman for the Wisconsin Humane Society said: “It can be an expensive disease to manage, which requires a monthly purchase of insulin and potentially other medical supplies.
“In total, this can cost hundreds of dollars a month, depending on your veterinarian’s assessment and the cost of supplies in your area.”
Explaining how the owner’s decision to give up her pet was an “act of desperation,” the charity thanked her for asking for help and trying to do better with her dog.
Speaking directly with the owner, the spokeswoman said: “First of all, we are very sorry that you had to separate from your best friend.
“It simply came to our notice then.
“We see your love in the bag that you carefully packed with all your favorite things.
“We see your love in the way you secured the belt so that it would not be hit by a car.
“We see your love in the way you placed her in the middle of a neighborhood where she would be quickly found.
“We see your love in how the girl looks happy and healthy.
“And we see your love on the note you left, asking someone to help you when you can no longer.”
Thanking the owner for putting Baby Girl first, the charity welcomes anonymous renditions without asking any questions.
“We see that you did what you thought was best for your beloved puppy and we are grateful for your compassion,” they added.
“She is safe, she is receiving a lot of attention from our team.
“We wish you all the best and hope that if you see this, you can rest a little calmer knowing that your baby girl has a bright future ahead.”
A few days after being taken in by the animal charity, Baby Girl secured a new home, and its previous owner could not be happier.
The spokeswoman added: “The international response to this puppy’s story has been overwhelming and the eagerness for kindness for its previous owner has really filled our hearts to the brim.
“We have been in contact with the previous owner and were grateful for the opportunity to connect with her and honor her wishes for the girl to find a new home.
“We passed on support resources that have been offered to her from this generous community. She expressed her gratitude and happiness to know that the girl would soon find her next loving home.”