Donkey milk even exist). In addition, the flavour and appearance of donkey milk have been found to be attractive to children. Equid (donkey and horse) milk can be considered a suitable substrate for probiotic beverage production. The use of fermented equid milk is an ancient tradition in central Asia, like koumiss or airag, a fermented mares milk very popular in Asia and Russia; but there are also traditional variants made from donkey milk. In Mongolia, where koumiss is the national drink, people have a saying that ‘kumys cures 40 diseases’. It is said that Cleopatra, Queen of Ancient Egypt, took baths in
Organic milk certified in order to be marketed as organic. In general, these laws require that livestock be allowed to graze on pasture, be fed organic certified feed (which may not include byproducts of animal slaughter), and that the animals not be treated with drugs (although it is also illegal to withhold necessary drugs from a sick animal in order to maintain that animal's organic status). Studies have examined chemical differences in the composition of organic milk compared with conventional milk. These studies generally suffer from confounding variables, and are difficult to generalize due to differences in the tests that were done,