ZooAmerica managed to breed the species a few years ago, but only have one animal now.
As did Beardsley, though I'm not sure the calf survived very long as they seemed to drop down to a single male very quickly after the birth (I think a first for New England?).
I'm not saying Pronghorn can't live and even breed outside their native range, they can (the nominate subspecies moreso than the SSP subspecies peninsularis). It just seems as though they do not thrive as well.
~Thylo