I noticed that Marwell Zoo in the UK has a herd of Nyalas with adult males that are castrated and look just like the females. Is this true for all spiral horned antelopes that if you have a breeding bull and want to bring in a new male to breed but keep the old bull and castrate it it will revert to the females' coloration? It seems like castration also not only changes the color but also additional characteristics like the longer hair on the back, neck and beard.
(Pic via Flickr)
(Pic via Flickr)