Doing this job is the Centre for Wildlife Rehabilitation and Conservation which has completed a decade of its existence in the state.
Director of Kaziranga National Park, N K Vasu, told PTI, "The rehabilitated rhinos are released back to the wild in the Manas National Park in an effort to refurbish the rhino population there after it suffered a near wipe-out a decade ago due to insurgency."
Vasu said the calves were bottle-fed formula milk every two hours until they were around two months old and around a month later they were given bits of grass to nibble at and eventually multigrain supplements.
Initially housed in the indoor nursery for stabilisation for varying periods of time depending on age, the calves are later transferred to one-acre outdoor paddocks within the centre, he said.
Unlike elephant calves that suckle for about three years in captivity, rhino calves get weaned off milk by about 18 months of age and they also start nibbling blades of grass much earlier than elephant calves.
While at CWRC, the calf undergoes treatment for injuries and is carefully nursed back to health by resident vets and keepers and once weaned, the calves are ready for rehabilitation to the release site, Vasu said.
A spacious "Boma" (a temporary enclosure) spread across 33 acres has been created at the Bansbari range in Manas where the rhinos are confined till they attain sexual maturity. After about three years of acclimatisation, the rhinos are let out remotely monitored round-the-clock with the help of radio transmitters.
As of May 2012, the forest department in association with IFAW and WTI have successfully released three rhinos in Manas and two more in Boma. Seven more calves are being nursed at CWRC and they will all be eventually moved to a suitable release site, Vasu said.
About three quarters of the world's population of greater one-horned rhinoceros is shared between India and Nepal, and Kaziranga National Park is the host to more than 2,200 of them.
The Chitwan National Park in Nepal has the second largest population of rhinos which is less than one fourth of the population in KNP.
Vasu said annual floods in the Brahmaputra plains resulting in the habital loss of rhinos and hunting of the animals for their horns have fragmented the rhino population into a few isolated pockets along its historical distribution range.