My fellow Zoochatters ... breeding at 14 - 16 is just that they are able to reproduce, yet this is far removed from the natural state where bulls do not sire offspring before late twenties and early thirties. Only at this age are they in their prime and are accepted by the mature and any cycling cows ... When bulls are younger they are just not perceived as a good suitor by your average elephant cow.
By and large what happened / happens in captivity is just an unnatural state of affairs and has only developed as all alarm bells went of ... say 3+ decades ago at the realisation that without any functional breeding groups in elephants both African and Asiatic elephants would eventually disappear from zoos in another 4 decades. That trend has been broken up in some Continents, yet is not as yet far from the ideal picture perfect frame.