After a diagnosis of cancer, Marian Hailey-Moss was worried about who would care for her dog, Ruffy, and her three birds, so she had a lawyer create a trust for her pets.

NEW YORK — When Marian Hailey-Moss was diagnosed with breast cancer last summer, the first thing she did was set a date for her mastectomy. Then she called a lawyer to create a trust fund for her 14-year-old dog and her three birds.

“I was very scared what was going to happen to me,” said Hailey-Moss, a psychotherapist in Manhattan. “I thought, who is going to take care of the animals? — because I have no family here.”

Hailey-Moss, 66, is divorced and has no children, but she does deeply love her pets. There’s Spiffy, her cockatiel, Winkin and Blinkin, her “challenged” love birds — challenged because they were born with deformed legs, not because they are not in love — and Ruffy, her terrier mix. “She’s just full of life,” Hailey-Moss said. “She’s slowed down a little now that she’s older, but she still may outlive me, you never know.”

Hailey-Moss set aside $24,000 for her pets. She named the administrator at Animal General, the veterinary clinic where she takes her pets, as both the trustee and the caretaker for the birds. Her dog walker is slated to take care of Ruffy.

In a nation that loves its pets, it is becoming increasingly common for owners to create trust funds for their animals, stipulating who should take responsibility for the pets and providing specific instructions for the care of the animals. Creating a trust fund that has an animal as the beneficiary is now legal in 39 states.

“There is a growing number of attorneys all across the country who are realizing that people have as much feeling for their pets as they do for their family members, and in some cases more,” said Peggy Hoyt, a trust and estate planning attorney in Oviedo, Fla. Hoyt, who has three horses, five dogs and five cats, is the author of the book All My Children Wear Fur Coats.

“If you think of an elderly person who lives alone with their cat or dog as their sole companion,” she said, “then they are probably closer to that pet then they are to any other human being.”

Since animals cannot speak out against abuse, neglect or the insufficient distribution of funds, Hoyt says it is crucial that pet owners carefully consider who will manage the money, who will care for the animals and who will enforce the trust. Sometimes, she said, it is a good idea to create what she calls an animal care panel, a group of people close to the pet who are charged with ensuring that decisions are made in the animal’s interest. A panel might include family members, friends and the animal’s veterinarian.

“Hopefully you build in enough safeguards with the animal care panel to protect the animals,” she said.

In addition, Hoyt said, instructions about how to care for the pet should be included in the trust. Hoyt recommends that her clients keep a notebook filled with all of the pet’s details, including its name, age, birth date, feeding routine, likes and dislikes, and any special medical concerns.