Inspired by this post on another website. If I have have a cat pee on a pregancy test kit, will it tell me if she’s pregnant? What about other mammals?
I’m aware that birds and lizards don’t really urinate in the same way we do, and indeed don’t really get pregnant in the same way we do, but would it also work for them?
For what it’s worth, my own cat is spayed.
Pregnancy tests test for a hormone called HCG, and the H stands for human, so I’m going to say no.
Say what? Sperm + egg. It’s the same basic setup in all vertebrates.
I believe most pregnancy tests use an antibody to bind hCG. I’d have to review the actual mechanisms of detection, but antibodies that detect proteins in one species can often recognize a similar protein in another.
I’ve actually done this in assays called Western blotting and immunocyto- and immunohistochemistry. The amino acid similarity between a hormone in one species to another in my case was about 65%.
So the answer is maybe. If you get a positive result it probably worked. If it’s negative, the cat might not be pregnant, the assay doesn’t recognize cat CG, or the test failed.
Uhm, only in viviparous ones. Lizards and birds lay eggs.
Don’t hit yourself that hard!
True with regard to sperm and ova, but they lay eggs and don’t have placentas that produce the hormone tested for in mammals.
ETA: Ninja’ed
Chorionic gonadotropin is the hormone used in humans that helps with alerting the mother’s reproductive system that it is pregnant and to stop cycling and get into pregnancy mode (simplification).
Different species use different hormones and methods to let the mother’s reproductive system know of the change in status from non-pregnant to pregnant. Not all of them use CG. I think horses use equine chorionic gonadotropin, with a similar end result, albeit different pathway (I think).
IIRC, cats and dogs don’t release an equivalent of hCG. Therefore, the test would not be useful.
In the documentary Godzilla, Matthew Broderick shows us how to test the pregnancy status of a giant mutant lizard using off-the-shelf kits. 
Interesting about cats and dogs. I was keeping it simple about the hormones. Birds get by with just the gonadotropins LH and FSH, for example.
A quick Google search seems to indicate you can buy ELISA kits for cat CG, but maybe they’re not useful for pregnancy status.
IIRC, human kits can work for horse. They taught an animal physiology lab in my department and used pregnant mare’s urine as the samples tested with a off-the-shelf pregnancy kit.
Curiosity made me take a second look at this and it does look like cats and dogs do not produce CG.
I actually know someone whose lab has used for a long time OTC pregnancy tests for use in testing if chimps were pregnant. So they at least work for out nearest relatives.
Yea, it would make sense, as the reproductive system is similar in primates. Not so much with other species.
IIRC, the corpus luteum in dogs, which secrete the hormones that would keep the uterus in pregnant condition, normally persist in the bitch’s ovaries, pregnancy or not, and they remain functional for a really long time. If the bitch becomes pregnant, the corpus luteum would continue working for most of the pregnancy (it is the default state). By the time it stops working, pregnancy is almost over and the hormones it produces are no longer required.
I forget the mechanism in the cats.
HCG can be used as therapy for some conditions, due to its effects on the reproductive system and hormone disruption it causes.
Unfortunately, my theriogenology textbook is in storage due to my moving. 
In my experience, a non-spayed cat who has reached sexual maturity almost always is either pregnant or nursing. (grin) When in doubt, spay.
An queen is going to be constantly either pregnant, nursing or in season, absent medical intervention. It’s the last bit that’s the real reason to spay.
Cats don’t really have any way to end their oestrus cycle,aide from pregnancy and birth, so once they enter the cycle, it continues until they fall pregnant. Queens in season are really prone to uterine infections. The longer the season lasts, the more chance of a fatal illness. Basically, if your queen ain’t spayed, she’s either gonna die if you don’t get some medical assistance, or she’s going to be pregnant.
I was thinking of this, but couldn’t remember the movie.
All:
Actually,I have had this idea for an SF story. The alien begins the story being pursued by the US Govt because they inadvertantly gave a sample of DNA that was then found to be alien DNA by the Govt…cue Bourne.
Here is an actually pee test for mares that is supposed to be pretty accurate: http://www.foalguard.com/marepregnancytestkit.htm
I don’t know if it works on humans or not.
For most other livestock, they test blood work for Pregnancy-Specific Protein B (PSPB).
Human pregnancy tests can sometimes come up positive from livestock, but it is a fluke of chemistry and not a reliable way to determine if the animal is pregnant. (In MOST cases, the human test will be negative even for a pregnant animal, because the hormone tested is typically very low or non-existent in livestock.)
They do have a short interestrus between cycles, and they are slightly photoreceptive (they cycle more frequently during longer day periods than during short day periods).
The worst is the ferret, the cycle without mating makes them anemic.
In both cases, they’re induced ovulators. They do not ovulate unless they are mated. Cats, IIRC, have a way of re-setting and going back into cycle (hence the interestrus). Ferrets suck at that, so they get stuck in a hormone mileu that makes them anemic.
I used to know a cat breeder. Cats are induced ovulaters, with the barbs on the tom’s penis causing ovulation. The breeder showed me how she would induce ovulation, thus temporarily ending estrus, in a cat she did not want to breed. She basically used a swizzle stick as a dildo. Seriously.
If I had a nickel for every time I heard that excuse …