Animal activists urged the government Thursday to ban the slaughter of donkeys for use in Chinese medicine, a practice which has soared in recent years and decimated African populations of the animal.
Donkey skins are exported to China to make a traditional medicine known as ejiao, which is believed to improve blood circulation, slow ageing, and boost libido and fertility.
It was once the preserve of emperors but is now highly sought after by a burgeoning middle-class.
People for the Ethical Treatment of Animals (PETA) said an investigation inside Kenyan slaughterhouses showed animals being cruelly beaten by workers, or dead after long truck journeys from neighbouring countries.
"PETA is calling for Kenya to join many other African nations in banning the slaughter of donkeys. There is simply no need for this cruelty, (the medicine) is not even something that has been shown to be effective," said PETA spokeswoman Ashley Fruno.
China is increasingly looking to Africa to satisfy demand as its own donkey population has nearly halved in recent years.
Several African countries have banned the export of donkey skins and closed Chinese-owned slaughterhouses, meaning thousands are now trucked long distances into Kenya from countries such as Ethiopia and Uganda.
"There are virtually no laws against the abuse of animals on farms or in slaughterhouses in Kenya, so none of the violence captured in the footage is punishable from a legal standpoint," PETA said in a statement.
The government has not responded to a request for comment.
John Kariuki, the manager of a slaughterhouse where alleged abuse was observed, said: "Whoever saw donkeys beaten inside my slaughterhouse is a liar and should look for something else to talk about."
Alex Mayers of the UK-based animal welfare organisation The Donkey Sanctuary said stories about the trade first began emerging in 2016, with tales of people waking up in the morning to find all of their donkeys had been stolen in the night, often skinned a short distance away.
"It started to happen across all corners of Africa, then even wider to Brazil, Peru, Pakistan, all over we were seeing the same photos, the same stories."
An investigation by the body in 2017 found the donkey skin trade was inhumane and "completely unsustainable", he said.
As the main export is the skin, "it doesn't really matter if a donkey is beaten or bruised by the time it is slaughtered, there is no incentive at all to keep donkeys in good welfare," said Mayers.
In Tanzania, there had been cases of slaughterhouse workers using sledgehammers to kill donkeys, he added.
"We've seen cases in Botswana where donkeys have been rounded up and machine-gunned. In South Africa slaughter operators have admitted using hammers to kill the donkeys, or... skinning them alive."
Mayers said the unprecedented movement of donkeys for slaughter was also being linked to disease spread, with Nigeria and Senegal having registered their first-ever outbreaks of equine flu this year.
In East Africa, there were an estimated 2.4 million donkeys, and between Kenya's four slaughterhouses and illegal traders, an estimated 2,000 donkeys were killed daily, he added.
If this continues, donkeys in the region could be wiped out in four years, said Mayers, adding donkeys were not like cows or goats that could be intensively bred.
Highly susceptible to stress, they do not do well in large groups and have a long gestation period of 12 months.
"The harder you try to reproduce them, the less successful it's likely to be, which is why China has not managed to sustain its own population."
Another Equine charity, Brooke, said it had noted 60 incidents of donkeys being stolen from Kenyan homes per week, at huge economic loss to their owners.
"Donkeys are not only key in helping with household tasks , they also enable owners and their families to make a living through a variety of commercial activities, for instance transport or agriculture," spokeswoman Megan Sheraton said.
A 2015 study by Brooke estimated the economic value of a donkey in Kenya at up to (Sh220,000) $2,200 per year.