It is the second week of January and you are building the annual report. You pull the number you are proudest of first. Four hundred and twelve surgeries. More than last year, more than the year before that, paid for with a grant you fought six months to get, a raffle, and two Saturdays you are never getting back.
Then you pull intake. It went up.
You sit with that for a minute, because somebody on your board is going to ask, and the honest answer is the one you do not want to say out loud. You are not sure the spay/neuter money is doing anything. You have heard your entire career that sterilization is the foundation. You have been doing it. The line has not moved. Maybe the money belongs somewhere it shows.
Do not move it. The program is probably fine. What is broken is the clock you are reading it on.
Most people in animal welfare treat spay/neuter as a volume problem. Do more surgeries, see fewer animals. It is a reasonable belief, it is how nearly every program gets funded, and it is how nearly every program gets reported. It is also why good programs get killed two years before they were ever going to work.
Spay/neuter is not a volume problem. It is a dose problem running on a biological clock, and hardly anyone is measuring it that way.
The number almost nobody runs
Beverly Ashton volunteered with Huntsville's spay/neuter effort after the city started funding it, then founded PAALS, a low-cost spay/neuter clinic in neighboring Limestone County, Alabama. She works from a model that turns access work into something you can put in a county budget
The unit is surgeries per 1,000 residents, per year. What it predicts is shelter intake, not the pet population. Nobody counts the pets in a county. Everybody counts what comes through the shelter door, and that is the number a commissioner is looking at anyway.
Three to four surgeries per 1,000 residents a year and intake keeps climbing. You are not keeping up with what is being born.
Five to six and intake holds steady, meaning you stopped the growth and gained nothing back.
Seven to eight, with eight as the target, and intake falls. Hold eight per 1,000 for five years and shelter intake gets cut roughly in half.
She derived those thresholds from three communities that landed in the same place around the same time: Huntsville, Alabama, Indianapolis, Indiana, and Jacksonville, Florida. It is field-derived operational guidance, not a peer-reviewed study, and it should be treated that way. It also assumes the rest of the picture holds still. Limestone County, where Ashton runs PAALS, is the fastest growing county in Alabama, so the target there has to be recalculated every year against a bigger denominator. Run your number annually, not once. It is also the only version of this math I have seen that a county commissioner can act on.
Now go run your own number. Annual surgeries, divided by the residents you serve, times 1,000.
Most programs land somewhere between two and four. That is not a failing program. That is a program dosed to lose slowly, funded and reported as though it were dosed to win.
Here is what that arithmetic looks like on real ground. Blount County, Alabama has about 60,000 residents and took in roughly 2,270 animals in 2025, about 38 per 1,000 residents, well above the rural average. At eight per 1,000, Blount needs about 480 surgeries a year. Not 480 total. Four hundred and eighty every year, for five years. Across the seven counties Animal-Angels Foundation serves, the same math comes to roughly 9,400 surgeries a year. The first time I ran that number I understood why nothing in our region has moved. Nobody is anywhere near dose.
Why year two was always going to look like this
Even at full dose, the calendar makes you look wrong before it makes you look right.
A cat reaches sexual maturity somewhere around six to nine months. Gestation runs about 64 days. A queen can produce multiple litters in a season. Spay a female cat in March and you have not prevented a single intake this year. You prevented the litter that would have come in the fall, the litters those kittens would have had the following spring, and every litter behind them. The first generation you erased would have reached your intake desk about a year out. The generation behind it, two years out. Year three is where the curve starts to bend, because year three is when the compounding you prevented would have arrived.
And you cannot see any of it. Absence does not show up on a dashboard. There is no field in your software for kittens that were never born. The only way that work becomes visible is comparing one year against a year several behind it, which is close to the one measurement no program is set up to make.
Beverly’s version of the curve is blunt about it. Years one and two, you will not see much. Year three, intake starts to fall. By year five, it is halved. Anyone promising a first-year drop is selling something.
Which means the two years when a spay/neuter program looks like a failure are the exact two years the biology guarantees will look like a failure. That is also when funders get nervous, boards start asking hard questions, and the line item moves to something with a photo attached.
You are not standing on flat ground
There is a second reason the needle feels stuck, and this one is recent.
In March 2025, Guerios, Clemmer and Levy published a follow-up study in Frontiers in Veterinary Science tracking 212 high-quality, high-volume spay/neuter clinics from January 2019 through June 2023. Those clinics performed 1,217,240 surgeries in the 2019 baseline year. The pandemic cut that by 13 percent in 2020, 3 percent in 2021, 6 percent in 2022, and 1 percent in the first half of 2023. They never rebounded. They were doing fewer surgeries per quarter in the follow-up period than they had done in 2021.
Extrapolated across the roughly 3,000 spay/neuter clinics in the country, the authors put the national deficit at 3.7 million surgeries. Their own caveat is the part that should stop you. That figure does not count the litters those intact animals went on to produce.
Shelter Animals Count found the downstream signal in its Altered Status Data Report, built on animal-level data covering more than 2.2 million cats and dogs from 262 organizations across 47 states. Between 2019 and 2023, the share of dogs arriving at shelters already sterilized fell from 33.2 percent to 22.3 percent. For cats it fell from 27.9 percent to 22.0 percent.
So the sector is not standing still and getting worse results out of the same work. The ground moved. A clinic performing the same number of surgeries in 2025 that it performed in 2019 is losing, because the unsterilized population it draws from grew underneath it. You are not disappointed because spay/neuter stopped working. You are disappointed because the field is three and a half million surgeries in the hole and running the same pace it ran before it fell in.
And we oversold it
There is one more piece of this, and this one belongs to us.
For decades the movement printed a number on flyers. One unspayed cat and her offspring produce 420,000 cats in seven years. In October 2006, Carl Bialik went looking for the source of that figure for The Wall Street Journal and could not find one. His own consultation with veterinarians and wildlife specialists produced a range closer to 98 to 5,000.
Even the low end of that is a serious number and a good argument for the surgery. But we spent twenty years advertising the fantasy version, and when a program puts in five honest years and does not produce a fantasy result, the people who paid for it conclude the work failed. The work did not fail. The promise failed. We wrote the promise.
What it looks like when the dose holds
Huntsville is the local proof, and it is worth being precise about it, because the story usually gets told wrong.
Between 2009 and 2014, citywide shelter intake in Huntsville fell from about 10,000 animals, more than 70 percent of them euthanized, to about 5,000. Over that stretch, according to Beverly Ashton, the city funded spay/neuter at $100,000 a year for five years and doubled it to $200,000 in one of those years. Surgeries ran about $100 through SNAP, with a separate fund covering families who could not manage even that. The city has kept funding spay/neuter since. The year-by-year figures after 2014 are not something I can put a number on.
Here is the part that usually gets left out. Spay/neuter was not the only thing that changed. The No Kill movement came to Huntsville and lobbied the city and its residents hard, and they were convincing. What the shelter adopted was a multi-part plan, and sustained spay/neuter money was one piece of it. Another was field practice. When an animal control officer picked up a stray, the officer had to check lost and found posts and ask neighbors whether anyone knew the dog before hauling it to the shelter. Another was a heavy push on large adoption events.
So Huntsville is not proof that dose alone cuts intake in half. It is proof that dose, held for five years, inside a system that also stopped counting findable owners as strays and worked the outflow end, cuts intake in half. That is the more useful lesson anyway, and it is the same one the end of this piece lands on.
Five years. Sustained money. A price low enough that nobody had to choose between the surgery and groceries, and a backstop for the people who still could not.
Huntsville did not find a better surgery. They found a way to keep paying for the same surgery after the excitement wore off, and they built the rest of the plan around it. That is the whole trick, and it is boring enough that it almost never gets copied.
Measure these five instead
Stop putting this year’s surgery count next to this year’s intake count. That comparison will punish you every single year for work that is doing exactly what it is supposed to do. Measure these instead.
1. Dose. Annual surgeries divided by residents served, times 1,000. Under five and you are losing ground. Five to six and you are holding. Seven or eight and you are gaining. This one number tells you more than your total surgery count ever will.
2. Duration at dose. Consecutive years you have held that number, reset to zero for any year the funding lapsed. This is the metric that predicts your outcome, and it is the one nobody tracks.
3. Coverage, not volume. What share of intact animals in your two or three highest-intake ZIP codes did you actually reach. Pets for Life found 88 percent of pets unsterilized in the underserved communities it worked in. Four hundred surgeries spread evenly across a county is a rounding error. Four hundred inside three ZIP codes is a program.
4. Altered status at intake. What percentage of animals arrive already fixed. This moves years before total intake does, which makes it your early signal that the dose is landing. Shelter Animals Count now publishes national figures you can benchmark against.
5. Intake by age cohort. Under six months versus adult. Spay/neuter shows up in the kitten and puppy line first. If juvenile intake is falling while adult intake holds flat, your program is working and what is left is not a reproduction problem.
The part the surgery cannot fix
One more thing, and it is the reason dose alone will not finish the job.
Roughly 30 percent of national intake is owner surrender, and the research on why is consistent. Cost first, then housing, then behavior. No surgery prevents an eviction. No surgery covers a $600 emergency bill on a Friday night. Spay/neuter shrinks how many animals arrive in the world. It does nothing about the reasons families let go of the ones already asleep on their couch. Run one layer and you will fix the litters while you keep losing the families.
That is not a reason to pull the spay/neuter money. It is a reason to stop asking one program to carry a job that takes two.
Year two is not a verdict
If you are two years in and the chart looks flat, you are not looking at a failed program. You are looking at year two.
The question in front of you is not whether to keep funding it. It is whether you are dosing high enough, inside tight enough geography, to still be running it in year five, when the number finally shows up.
Join the shift to prevention.
Donate to Prevention and fund what happens before the shelter.
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Sources
Ashton, Beverly. Founder, PAALS (Limestone County, Alabama), and volunteer with the Huntsville spay/neuter effort. Dosage model and five-year curve, thresholds derived from Huntsville, Alabama, Indianapolis, Indiana, and Jacksonville, Florida. Field-derived operational guidance captured in conversation June 2026, corrected by Ashton August 2026. Huntsville intake decline, city funding history and multi-part shelter plan per Ashton.
Guerios SD, Clemmer G, Levy JK. The pandemic’s cruel aftermath: progressive decline in spay/neuter capacity. Frontiers in Veterinary Science, March 21, 2025. doi:10.3389/fvets.2025.1558235
Shelter Animals Count. Altered Status Data Report, 2019-2023. A program of the ASPCA. https://www.shelteranimalscount.org/altered-status-data-report/
Shelter Animals Count. 2025 Annual Data Report. A program of the ASPCA. https://www.shelteranimalscount.org/2025-report
Bialik, Carl. Trying to Herd a Cat Stat. The Wall Street Journal, October 12, 2006.
Blount County, Alabama animal census reports, 2025 intake figures, compiled at BlountAnimals.com/shelter-data.html
Humane Society of the United States, Pets for Life. Community sterilization findings, 88 percent of pets unsterilized in underserved communities served.
Pizano, Sara. The Go-To Guide for Animal Services, 2026. Owner surrender share of intake and cost-driven surrender findings.
Hello-what about the idea that we are not
reaching the right people. I failed miserably to reach the people at the root of the problem. They put up roadblocks-they didn’t want to neuter Sparky, they wanted Fifi to experience having puppies, etc. Most failed to show to appts, refused help, and rural ACOs either are apathetic or understaffed.
Beautiful breakdown of what it actually takes to affect real change. An area to explore are the outrageous ‘low cost’ prices offered by humane societies - it’s almost like they really don’t want spay and neuter to succeed.