I have not tried a vertical as I wanted to include the whole body of the adult, but I will give it ago. Did you crop at the rear of the youngster and leave a reasonable amount of room out front?
Excellent light and details in the fur Ken. Like the head angles. Be good to see variations on crops, but that's for interest rather than preference as like this as presented.
Ken, I like both the original and your repost with the entire calf. Details, light, and comp work very well. A very fine image of one of my favorite antelope.