Twelve months of recorded matings with no pregnancy is where guessing stops being cheap. The workup is 6 steps, takes 3-6 weeks end to end, and costs roughly $400-1,200 per cat in US practice. Run them in order. Skipping the $90 swab to jump straight to hormones is how a cattery loses 2 years on the wrong cat.
Why 12 months is the right threshold
Count exposures, not heat cycles. A queen bred on 3 separate heats across 12 months with no litter has a real problem; a queen bred twice in 14 months may simply have been mistimed. Queens are seasonally polyestrous and, above 12 hours of daylight, cycle every 2-3 weeks from late January to September. Below 10 hours of light most stop cycling altogether, which is normal and not infertility. Then count the other side: 1 tom failing with 6 queens points at him, and 6 toms failing with 1 queen points at her. Write both numbers down before any test.
Step 1 and 2: the log, then the physical
Build a table of 12 months of dates: heat start, mating days, whether a mating was seen completed, and any return to heat 21-25 days later. A queen that comes back into heat on day 21 is not automatically infertile — early embryonic loss produces the same calendar, and it is a different diagnosis with a different plan. The physical then covers 6 things: body condition score, weight trend, vulvar discharge, mammary glands, teeth and gums, and coat. A score of 4/9 or lower suppresses cycling in some queens, and a low-grade dental infection is a plausible enough cause that it gets fixed before anything expensive starts.
Step 3: the swab and its 48-hour culture
Take the swab before mating, never after, because semen and normal flora make a post-mating culture unreadable. A guarded swab reaches the lab within 24 hours; the culture reads at 48 hours. Ask for 3 things on the report: colony counts, organism names, and a cytology note on neutrophils. A pure heavy growth of 1 organism alongside neutrophils is worth treating. A mixed light growth of 3-4 organisms usually is not, and treating it costs $60-150 and buys nothing but resistance. Mycoplasma and Streptococcus canis are the 2 worth naming specifically, since both need different handling from a routine coliform.
Step 4: progesterone every 2 days
One sample proves nothing. Bleed every 2 days starting from the first day of standing heat, so the curve shows direction rather than a single point. Ovulation in the queen is reflex, follows a successful mating by roughly 24-48 hours, and the corpus luteum then holds progesterone for 60-65 days if a pregnancy is present. Values below 1.0 ng/mL on day 4-6 mean ovulation did not happen, which changes the plan to timing rather than treatment.
| Day from first mating | Progesterone (ng/mL) | Reading |
|---|---|---|
| 0-1 | under 1.0 | Pre-ovulatory; mating window still open |
| 2-3 | 1.0-2.0 | Ovulation underway |
| 4-10 | 2.0-6.0 | Luteal tissue working |
| 10-25 | over 6.0 | Consistent with pregnancy or pseudopregnancy |
| day 6 | under 1.0 | Ovulation failed; re-time the next cycle |
Do not treat a flat curve at home. Any hormonal decision belongs to the vet, on prescription, after the curve and the ultrasound agree.
Step 5: ultrasound at day 21-25, plus the tom
Ultrasound at day 21-25 shows fluid, and by day 28 a heartbeat; radiographs only become useful after day 45, when the skeletons mineralize. A negative scan at day 25 with a documented ovulation moves the diagnosis to early loss or failed conception, and the questions change. The tom gets 3 checks: testicular size and symmetry, a semen evaluation where a lab offers one, and a review of his last 12 months of litters. A stud used every day for months can drop sperm quality, so most are rested 2-3 days between matings, and a full spermatogenic cycle takes 30-60 days to recover.
Step 6: genetics on both sides
DNA does not explain infertility, but it decides whether the pair should be bred at all. Run the breed-relevant panel on both cats: HCM, PKD, PRA-b, SMA, and blood type. Two carriers of the same recessive condition is a stop. Blood type matters more than most breeders expect: a type B queen with a type A tom can produce neonatal isoerythrolysis, which looks like fading kittens at day 2-7. Results take 10-14 days, so order them on day 1 of the workup, not at the end.
Six weeks, in a workable order
Week 1: log, physical, swab, DNA panel posted. Week 2: culture back at 48 hours, progesterone series started at the next heat. Week 3-4: second and third progesterone samples, ultrasound at day 21-25. Week 5: tom assessed, semen result in. Week 6: sit down with 1 page of results and decide. If the queen is cycling and the tom is clear, the next step is a re-check at 2 cycles rather than more tests.
When to stop, and what a second opinion buys
Set a ceiling before you start. Two full cycles of workup, about 18 months and $2,000-2,800, is where most breeders stop and either retire the queen to a pet home or change the pairing. A second opinion from a theriogenologist costs $150-350 and is worth it at 1 specific point: when the progesterone curve says ovulation happened and 2 ultrasounds at day 25 were negative. That combination has a short list of causes, and a specialist reads it faster than a general practice.
Four things to do this week
- Write the 12-month mating log, with counts for both cats.
- Book the physical and the pre-mating swab for the next heat, not this one.
- Order the DNA panel today, since it takes 10-14 days.
- Put the expected spend into the cost calculator and set the ceiling.
Read which tests are worth ordering before you pay for a panel you do not need, and compare the pair against the pairing rules for genetic testing — a bad pairing produces infertility-looking repeats that no swab will fix.
Terms mentioned in this article
Frequently asked
How long should we keep trying before starting the workup?
Twelve months of recorded matings on at least 3 heats is a reasonable trigger, and 6 months is early unless the queen is over 6 years old or has never conceived. The exception is a queen with a history of returning to heat at day 21 every time, which suggests early loss and deserves the workup sooner. Write the dates down from the start, because memory is unreliable after 2 seasons.
Can a single progesterone test rule out ovulation?
No. One value tells you the level at that hour and nothing about direction, and a sample taken on the wrong day can read low in a cat that ovulated normally. The useful pattern is 3 samples at 2-day intervals starting from the first day of standing heat. If the series stays under 1.0 ng/mL through day 6, ovulation did not happen and the plan shifts to timing.
Is the swab painful, and does it need anesthesia?
A guarded vaginal swab is a short procedure and most queens tolerate it with gentle restraint, though some need a light sedative by prescription. It should be taken before mating, and the sample goes to the lab within 24 hours because the culture reads at 48 hours. Ask for colony counts and cytology, not just a list of organism names, or the result cannot guide a decision.