As African swine flu - better known as 'pig ebola' - continues to ravage Chinese pig farms, triggering a massive surge in pork prices, we've written about how consumers' search for alternatives to the dietary staple has turned duck farmers into millionaires overnight.

But duck isn't the only protein alternative that Chinese consumers are buying up in droves as pork prices have climbed nearly 70% over the past year, to near-unprecedented levels.

As China Dialogue, a China-based English-language publication, reports, surging demand for Donkey meat and skin in China is rapidly depleting donkey stocks in Kenya. If demand continues to climb, animal rights activists warn, the Kenyan Donkey could soon disappear from the East African country.

Over the past five years, four new donkey abbattoirs have opened up in Kenya to help meet rising demand in China. This, of course, predates the 'pig ebola' outbreak, as the Communist Party and state-backed agribusiness has struggled to source food for China's 1.4 billion consumers even under normal conditions.

Though most US consumers would probably cringe at the thought of eating donkey, their meat is considered a delicacy in China. Their skins are also processed into a traditional remedy called ejiao that's used to treat everything from anemia to dizziness. Ejiao has also grown in popularity alongside China's growing prosperity.

According to a report by the African Network for Animal Welfare, the slaughterhouses are operating at less than half of their capacity, as demand from China has already depleted the donkey population from around 1.8 million animals in 2009 to roughly half that level - about 900,000 - today.

Some activists have warned that Chinese demand is making the Kenyan donkey trade 'unsustainable'. Like other forms of livestock, donkeys are slow to reproduce, with gestation periods of 11-14 months.

The rising demand has also caused the price of donkey meat to soar. Today, one donkey can fetch a price of between 15,000 to 25,000 Kenyan shillings ($145-$242), up from 6,000 to 8,000 shillings ($58 to $78) four years ago. Males typically cost more.

This could create serious problems for the local economy. Many Kenyans rely on donkeys for transportation, particularly in the northern part of the country, where donkeys pull carts that carry water, firewood and other supplies. Higher donkey prices mean these staples are increasingly out of reach for the average merchant or farmer.

The Kenyan government is facing criticism for not exercising more oversight of the abbattoirs. Some believe the government could have implemented breeding programs to ensure that donkey stocks would keep up with rising demand. Others believe it's too late for any remedy short of calling for a total ban on the trade in donkey meat and ejiao (though it's unlikely Beijing would let that happen).

As the the swine flu outbreak worsens, news reports earlier this week claimed that Beijing is on the verge of releasing some of its emergency pork reserves as the number of pig casualties from the swine flu crosses 100 million, equivalent to one-third of China's pig population.

That doesn't bode well for the donkeys.