Donkeys immune to botulism?

I just read a World War II anecdote about botulism toxin being smuggled into China for use on Japanese officers by the resistance. To insure the plan would work, the local resistance tested the poison on donkeys, and abandoned it when the donkeys showed no ill effects. Ironically, the story went, donkeys are one of the only animals immune to botulism.

Is that true? Are donkeys immune to botulism? A quick google search brings up general warnings for all equines.

If they were they aren’t any more:

(PDF Warning)

Vultures are broadly immune to several infections found in rotting carcasses, including botulism, cholera and even to anthrax.

Sadly, what they’re not immune to is a veterinary drug used to treat cattle that is poisonous to vultures. Indian vulture crisis - Wikipedia

Vultures are broadly immune to several infections found in rotting carcasses, including botulism, cholera and even to anthrax.

Sadly, what they’re not immune to is a veterinary drug used to treat cattle that is poisonous to vultures. Indian vulture crisis - Wikipedia

You can say that again!

Chronic Hysteresis. It happens.