I wanted to use the growth rate to evaluate my care. It seems that the isn't any data out there on rhino growth rates...captive or otherwise. Sounds like a mission to me (dumdadum)! I'll be sure to post anything I find.
By the way, I found it pretty stressful (to the animal) to get accurate length measurments. So I stuck to weight. This is strange because Orson lets me do anything to him. I can turn him on his back...he'll even eat while I hold him in a closed hand!