Rhino conservation question

[Mr. 16 gauge]

With all the hullabaloo over the taking of a black rhino in Namibia by a sport hunter, I was reminded of seeing a TV program (documentary? I can't remember) on conserving rhinos, and one group (I believe they were hunters/sportsmen) were trying to bring captured rhinos here to the States (it was somewhere in Texas, IIRC) and raise them on ranches, with the idea of repatriating them back to Africa once their breeding programs took off. This was decades ago, so the details are quite hazy.......but I'm wondering if this idea ever became a reality, and if not, why not? Seems to me that (at least on the surface), it would be a good idea.....animals would be protected from poaching, well managed, good vet care, etc. Seems like if it would work for species like black buck antelope, it should work for rhino. Were there unforseen problems? I do remember them doing an interview, and there was a rhino in the pen behind the interviewers (I would assume for "effect"), but that was the last I heard of it.
I have no intention or desire to hunt a rhino, but I would like to be armed with facts, as I'm sure I'm gonna catch hell from the antihunters at work. I was baited last night into a 'discussion" at a dinner meeting....didn't fall for it, though. (it was about plains game hunting in Africa; I was just too tired, and a bit wary, to launch into a diatribe).
Thanks for any light you can shed on this...........it's much appreciated.