Four springboks, transported from Hamilton Zoo to Wellington Zoo, have died from a combination of "capture myopathy" and heat exhaustion.
While two were found dead on arrival on August 9, the other pair died within the following 17 days.
Hamilton Zoo manager Stephen Standley said the animals had
suffered stress which caused a natural breakdown in their muscles, which he referred to as "capture myopathy".
This was brought on by the springboks' capture and containment.
The animals, four of about 32 in captivity throughout New Zealand, were transported by road inside special crates, Mr Standley said yesterday.
Hamilton Zoo staff had been responsible for taking the springboks to Wellington and had stopped every hour to check their state, but this had not been enough to prevent the tragedy.
"They were concerned about one animal but it was thought it would calm down en route."
The animals' body temperatures had built to levels that had exhausted them, and capture myopathy was not a condition that was easily reversible.
Lessons had been learned, Mr Standley said. "It's a topic of discussion at a zoo forum at the moment. Its focus will be improved systems for catching and transporting antelope."
It was a natural reaction for any African antelope to run when it was chased, he said.
"They were tranquillised, but not sedated."
The dead antelope were described as four castrated males. Mr Standley said no springboks had been imported to New Zealand for at least t seven years.
Most of the remaining springboks lived at zoos in Auckland and Christchurch.
