Yeah, if you want to know if your livestock is pregnant, I’d used an appropriate test.
My original point in this thread was to reply to the speculation that a test for hCG wouldn’t work in another species because the “h” stood for human. It turns out that in the case of cats and dogs, it wouldn’t work because they don’t have CG. In the case of horses, it may work because they do have CG. There are antibodies that can recognize the same proteins across several species (and I’m using same protein in the sense of an ortholog). I know this because I’ve done cross-species immunoassays against protein targets and not just between mammals.
As a practical matter, the physiology lab used human over-the-counter kits instead of a horse kit because they were cheaper and they wanted to save money. The kit in your link was almost $40 versus less than $10 for a OTC human kit. IICR, students were given unlabeled urine samples from pregnant or non-pregnant mares and they were to use the kits to determine the status of the mare their sample came from. Whatever brand they used was accurate enough to do that in this particular example (a lab that is offered every year, so I imagine they have a large sample size going back for years to determine the accuracy of the kit they use).
