JOHANNESBURG — The killing of dozens of lions on a South African farm last week has led to increased scrutiny of the country's policy allowing the annual export of 800 skeletons of captive-bred lions to meet demand in Asia for bones.

The SPCA animal protection group in Bloemfontein is preparing to file a formal complaint alleging abuse by the farm's owner and foreman, said Reinet Meyer, a senior inspector for the group. She said a total of 54 lions were killed at the farm over two days.

Meyer also said she saw two lions that had been kept in transport crates for several days, and described the conditions in which the lions were kept as "totally unacceptable."

The killing of captive-bred lions is not illegal in South Africa if permits are in order. Conservationists, however, say enforcement of regulations governing the lion bone trade is weak and that the legal market could threaten Africa's wild lions by spurring demand for skeletons.

Authorities in Free State province are investigating allegations of misconduct on the farm where the lions were killed.

"All permits relating to this matter have been suspended until further notice," Dirk Hagen, a provincial official, said in a text message to The Associated Press.

African lion bones started to become a substitute for tiger bones in traditional medicine in China and Southeast Asia after tiger populations dwindled and stronger conservation measures were put in place to protect them.

Legal exports of South African lion skeletons increased from about 50 skeletons in 2008 to nearly 600 several years later, and South Africa last year announced an export quota of 800 captive-bred lion skeletons.

There are several thousand wild lions and roughly 8,000 captive-bred lions in South Africa, according to Andrew Venter, executive producer of "Blood Lions," a documentary that explores lion breeding in the country.

Many captive-bred lions are killed by paying clients in a practice described by critics as "canned hunting."