South African police say they are investigating the illegal donkey skin trade after seizing 5,000 hides in a recent raid east of Johannesburg. Police suspect the skins found at a farm in Benoni, last week, came from illegally slaughtered animals whose hides were destined for China.

They described the raid as a major breakthrough against smugglers. Trade in donkey skins is worth millions of dollars, with hides prized in China for supposed medicinal properties.

The gelatine in the hides is used as a medicinal tonic, with some believing it can slow down menopause in women.

It is also used to try to treat conditions such as insomnia and poor circulation.

The raid in Benoni followed a tip-off from a woman who had complained about the smell of rotting meat.

Police did not make any arrests at the farm but have said the raid provided important new information about a syndicate suspected of slaughtering the animals and transporting the meat and hides, without them being certified disease-free.

South Africa’s Mail & Guardian newspaper said Chinese nationals were suspected of involvement.

Agencies