@docend24: From my point of view & experience, medical training can be a great alleviation for both animals and staff. In the best case, I don't have to knock the animal down, corner it or wrestle it to the ground for routine and minor procedures. If well done, this means less stress and risks for both animal and staff and makes some new forms of husbandry possible. It can even help to avoid problems and achieve better treatment, like teaching apes to bring lost items or their youngs to the keeper. The training seems even to be appretiated by the animals themselves-otherwise they wouldn't approach and follow the commands. Especially in terms of "intelligent" species, may they be primates, parrots or Komodo Dragons, such training might even serve as mental exercise to fight boredom. And by doing so, the zoos can actually really contribute in terms of education and scientific research-see observations on Cuban crocodile behaviour and intelligence. To achieve such positive conditioning, the learning patterns have to be repeated, using different training devices such as staffs. "Poking" is clearly the incorrect description of the zookeeper's careful usage of his staff in the video.
Animals in a zoo exhibit don't live in an impenetrable stasis field where nobody has access. The zoo staff has to work out-and inside the exhibit and quite often, with the animals themselves. Therefore, training alleviating the necessary work for all involved is, "imho", wise and reasonable.
If You don't want to see such training, better watch animals in the wild-or just visit the exhibit outside the training sessions, to see their "natural beauty"...
