Dozer was born on April 27 and, due to his tiny size and delicate nature, has had to be hand-reared from day one to ensure his survival.
Now visitors will get the chance to see him when he celebrates his ‘should-have-been-birthday’ on June 24.
Maxine Bradley, zoo curator, admitted: “This is not something that we would normally celebrate.
"However, Dozer is not a normal calf and he has truly surprised everyone, including our vets, Robson & Prescott’s, who have been shocked by his survival since day one.
“It has been an incredibly tricky and difficult rollercoaster for us as we explored the unknown territories of premature calves.
"There is practically no information available for calves born this early, so every day brought a new challenge. We just can’t believe he is still with us.”
The calf spent many nights travelling home with the keepers, as he needed frequent feeds throughout the night and he needed to be kept warm as he was not able to thermo-regulate and keep himself warm.
The zoo also had to come up with an alternative size of teat for his milk bottle as his mouth was simply not big enough to fit around the normal calf-sized teats.
Lucy Edwards, head keeper, added: “We were happy to keep going with him as he had so much will to live, if he kept trying, we did too. Some days were so difficult and we thought we were going to lose him and the next day he would be up and running around, he kept us on our toes!”
A typical calf to a highland cow is born after a gestation of 280 days and weighs about 30-32kg.
Dozer was born after a gestation of no more than 227 days and weighing only 8kg.
"That such a calf should be born alive so prematurely is incredible and certainly not something the vets in our practice have ever experienced,” said Sam Prescott of Robson & Prescott.