Looks like any number of the hundreds of mid-term abortions I've posted over the past 30 years. Nothing grossly abnormal about it that I can see... other than...it wasn't ready to be born yet. At that stage of development, they're all kind of 'juicy'...
In this vicinity and at that stage of gestation, I'd bet you a Coke that it's a Neospora abortion, but without a diagnostic workup, that's merely playing the odds.
Freeze back an ear? Sure... doesn't take up much space in the freezer... and until you start counting 'one', there's no record of or way to define a defect. Had one show up in my own herd... Angus sire we'd purchased was evidently the 'founder' of the Angus SCN defect... but until I had the third affected calf born, I didn't start freezing back samples... but by the time #9 or 10 had arrived, I had quite a bit of material stored back for the geneticists to work with.