@Cordialemente,Dottore .... I was referring to a very long time ago!
I know it is close to home and please do not take it as critique. It was the state of affairs years ago with Italian zoos in general. Since, the 2000's the situation has much improved if not massively and some fine new modern zoos have come up. I actually value some of the city zoo's like yours and Parco Natura Viva among the best over the mundane safari parks (Fasano and Pombia).
For bongo Le Cornelle has maintained a nice herd. End 2018 they held 3 females. I assume Le Cornelle have now acquired a bull to breed (I did see some footage of a youngish calf on the site). Any news on their bongo is hard to come by though on their website or FB (I gave up).
At the moment there are still only 3 females, but the plan is different for the near future
If you want to come again to Italy, tell me when...and we can meet somewhere visiting colleagues in the zoos of Northern Italy, even in my institution.