Dr. Kim Culbertson, a Twin Cities veterinarian, worked for the Animal Humane Society for a decade, witnessing scores of happy adoption tales. She saw her share of heartache, too.

"Tens of thousands of animals came through the door unwanted, injured, homeless," she said. "And there was no concerted effort to prevent it."

Now there is, thanks to Culbertson and her small, very busy crew. Culbertson is founder of MN SNAP, or Minnesota Spay Neuter Assistance Program, a two-year-old nonprofit. SNAP owns the state's first mobile unit, which provides low-cost, high-quality, spay/neuter services to rescue groups, shelters and low-income pet owners.

On Tuesday -- World Spay Day -- Culbertson, two fellow vets and 10 staff members hope to spay or neuter about 90 animals. In addition, more than 25 Twin Cities vet clinics will perform the procedures, donating the fee proceeds to MN SNAP "to show their support of this issue," said SNAP board member Britt Gage.

We all should show our support.

While SNAP has spayed or neutered nearly 14,000 dogs and cats (and many rabbits) since its inception, its workload remains immense. One study estimated that 90,000 pets are put to death annually in Minnesota due to overpopulation. Cost of spaying or neutering, which averages $300, often is a barrier.

SNAP surgeons charge only $40 to $70.

The mobile clinic operates seven days a week by appointment (go to www.mnsnap.org or call 612-720-8236), averaging 35 surgeries a day. It travels wherever it's invited, from people's driveways, to college campuses and community centers, to an armory in Brainerd.

The truck will make seven trips to Indian reservations in 2012. In addition, a PetSmart grant will allow MN SNAP to assist qualified pet owners in north Minneapolis, where the highest number of animals are surrendered annually.

The most exciting news for Culbertson's crew is that SNAP will take over a surgery suite in early March at Minneapolis Animal Care and Control four days a week, providing upwards of 7,000 additional surgeries annually.

Wrapped in a tiny pink sweater, 2.9-pound Jasmine the Chihuahua was snoozing away blissfully in the SNAP truck last week, unaware that she was part of the impressive effort.

"It's a much-needed service," said Dr. Lisa McCargar, a vet who joined SNAP two months ago. "People drive up to two hours to our clinics."

Culbertson agreed. "People are extremely grateful," she said. "We get hugs, tears, cards, cookies. We all thought this would be good for the animals. Then it dawned on us that this was also good for owners. Pets are cherished family members."

gail.rosenblum@startribune.com • 612-673-7350