Yes Daddy, No Mommy

What to make of UC Davis lab report that says 2022 foal is NOT out of his dam?

Report confirms stallion. But somehow dam is “excluded as possible dam?” Icelandic. Dam has one coming 4yr registered offspring .

I think the first thing I would do is repeat the testing with new sample(s) to rule out any contamination, damage, lab error, etc.

I’m assuming there’s no possibility of something weird like an embryo transfer where things got crossed with two different dams?

Was the foal being tested against a current sample from the dam or is her DNA on record? Could there be an error with the DNA on record?

Also mare could be a chimera… if all other error is ruled out, maybe something to look at.


One coming 4 yr old was confirmed out of dam with dams recorded DNA. There is one unrecorded coming 9 year old. He was an unplanned import “bonus baby.” Maybe time to test that one and see what comes up there.

If the dam is a chimera, this could occur. If a repeat test shows the same result, that could be something to explore.


I’m eager for updates on this story if/when they figure it out! What an interesting result.


Did the mare and foal come from a farm with multiple mares and foals? Could foals have been switched/stolen by the mares? Or if the 2022 foal has already been weaned, again, was he weaned with other foals? I know a lot of Icelandics are bred in herds which are sometimes large - foal swapping isn’t common, but it happens. Maybe it’s a simple case of misidentification. (Not simple to resolve, I’m sure, especially if they’ve already been imported, but simple in terms of a reasonable answer.)

If the mare foaled while with you and you’re certain that the mare is, in fact, the mother of that foal, then I’d go with chimera. What do the mare and foal look like?

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Either the dam swapped foals with another mare shortly after birth, or the mare is a chimera. If UCD still has the samples, you could ask for a re-test.

UCD actually just goofed in a way in color test I recently saw (like recent, last few weeks). The foal had to be homozygous Dun by way of tested parents both being DD. However, the results came back as “dd”.

Years ago that might have been an accepted way to denote “not dun at all”, but with the discovery of nd1 and nd2, it’s not (not to mention the foal HAD to be DD).

UCD simply didn’t capitalize the results. All that is a roundabout way of saying - maybe it’s a mis-type on their end, rather than a faulty test.

If you need to test for chimera after you ask them about the results, you’ll need to pull hairs from the mare from various body parts - mane, tail, even body if you can (ouch), but ask UCD what they want out of that