"It's gruesome," a source at the reserve, who wanted to remain anonymous, told Die Burger .

"It just f***ing blood. They didn't even use a chainsaw to take off her horn. They used a machete or something to hack it out."

Joe Cloete, the managing director of the Schamwari group said the killing was a tragedy.

The last time a rhino was killed at the reserve was in December 2008.

The rhino cow and her male calf had bee shot with a tranquilliser.

The source said the calf survived because its horn was neatly sawn off. The rhinos were found beside a waterhole.

By Monday afternoon, the calf's chances of surviving looked good, Cloete said.

"He is under the supervision of our vet Dr Johan Joubert and will be taken to our animal rehabilitation centre, " Cloete said.

Last week, the World Wildlife Fund said the number of rhinos poached in South Africa had reached a record high.

Statistics from SA National Parks show that 341 animals have been lost to poaching so far in 2011, compared to a record total of 333 last year, the fund said in a statement.

Two more rhinos were killed in Mpumalanga at the weekend.

The latest Eastern Cape killing would bring that number to 344.

Three of the five rhino species globally are critically endangered.