They started arriving the night before, determined to be among the first in line when the doors opened in the morning. With their dogs by their sides and cats cozied in carriers on their laps, families settled in to wait for the sun to rise on the Spayathon™ for Puerto Rico, the largest known spay/neuter collaboration in the world.
An HSUS-led coalition of more than two dozen organizations has already sterilized and vaccinated nearly 25,000 animals since the initiative began last summer—and they’re not done yet. With the support of Governor Ricardo Rosselló and First Lady Beatriz Rosselló, the initiative will most likely reach a total of 30,000 pets by the time it wraps in May.

To make it happen, expert teams of veterinarians, vet technicians, animal welfare advocates and volunteers set up no-cost clinics in sports arenas and other large spaces across the island. Over the course of several days, the teams spay/neuter and vaccinate hundreds of pets and send their families home with pet food, leashes, toys and other supplies—all for free. The program includes training for local veterinarians, who will keep all of the equipment brought in for the clinics, allowing them to sustain the effort long-term.
Sterilizing 30,000 cats and dogs will prevent the births of approximately 200,000 puppies and kittens in the first year alone.
ASPCA
“This is the first time high-quality, high-volume spay/neuter of this magnitude has ever been done anywhere in the world,” says Tara Loller, HSUS senior director of strategic campaigns for companion animals and the creator of the Spayathon. “I am extremely proud of this work—it’s truly been a dream of mine since I stepped foot on Puerto Rico in 2014.”
To carefully and quickly sterilize hundreds of animals each day, the teams follow strict safety protocols and meticulously devised procedures. While each clinic wants to serve as many animals as possible, “quantity never trumps quality,” says Lindsay Hamrick, HSUS director of public policy for companion animals, who worked as a team leader during the first two rounds of the Spayathon (the third round completed in February and the final round will be in May).
Workers at each clinic ensure that animals have enough safe space between them in line and throughout the registration process, and provide water both for people and pets. Families stay with their pets through the veterinary examination, not leaving their side until they’re nodding off from the anesthesia and reuniting with them as soon as they start waking up.
“We make sure the families are with their pets as much as possible,” says Kari Nienstedt, HSUS senior director of council engagement and a Spayathon team leader. “It’s less stressful on the people and the animals, which makes it safer for everybody. The last thing the animals remember and first thing they notice when coming out of surgery is that they’re with their family, which is great.”


After a vet tech evaluates the animals and gives the green light for them to go home, families receive a rabies vaccination certificate, pet supplies, recovery instructions and access to follow-up care in case they have any medical concerns after the clinic closes.
The hours are long—with staff arriving before 6 a.m. and not locking up until well after 9 p.m.—but the rewards are many, Nienstedt says.
“We know what this means in terms of how many animals we’re helping now and how many litters that’s preventing in the future,” she says. “There certainly are challenges, but the cohesion and collaboration among the partners is unbelievable. We’re all on the same team with the same goal.”
There certainly are challenges, but the cohesion and collaboration among the partners is unbelievable. We’re all on the same team with the same goal.
Kari Nienstedt, The HSUS
Story after story
Ask Loller, Hamrick or Nienstedt which encounter has had the most impact on them, and the answer is the same: There are too many to list. The elderly man who strapped his cat’s carrier to his bicycle and rode 20 miles to the nearest clinic. The woman who waited all night at the front of the line and, instead of resting, picked up a broom and started helping the staff clean while her dog was in surgery. The woman who bedazzled her cats’ cardboard carrier so they’d travel in style. The man who came back every day after his pet’s surgery to help translate at the registration table. The man who spontaneously broke into a speech of gratitude in the waiting area, drawing cheers and applause from the 100 or so people nearby.
Every day, at each of the eight locations, there were lines around the building full of people who had gone to extraordinary lengths—traveling long distances, missing work, forgoing repairs to homes still damaged from the hurricanes—to make sure their animals got the care they deserved, Nienstedt says.
“Every single one cared enough about their animal to spend a significant amount of time waiting in line—without exception, every person who came through the door,” she says. “How loved these animals are.” Here are some of their stories:
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