Donkey milk (or ass milk, or jenny milk) is the milk from the domesticated donkey ( Equus asinus). It has been used since antiquity for cosmetic purposes as well as infant nutrition.
Hippocrates (460–370 BC) was the first to write of the medicinal use of donkey milk and prescribed it for numerous conditions, including poisoning, fevers, infectious diseases, edema, wounds, nose bleeds, and liver trouble.Hippocrates. The Genuine Work of Hippocrates. Vol. 1. Sydenham Society 1843 In the Roman era, donkey milk was a recognized remedy; Pliny the Elder (23–79 AD) in his encyclopedic work, Naturalis Historia, wrote extensively about its health benefits, i.e. to fight fever, fatigue, eye strain, weakened teeth, face wrinkles, poisonings, ulcerations, asthma, and certain gynecological troubles.Pliny the Elder. The Natural History. Book XXVIII "Remedies derived from living creatures". John Bostock 1855. However, it was not until the Renaissance that the first real scientific consideration was given to donkey milk. Georges-Louis Leclerc the Comte de Buffon (1707–1788) mentions the benefits of donkey milk in his Histoire naturelleLeclerc GL. L’Histoire naturelle, générale et particulière, avec la description du Cabinet du Roy. Tome Cinquième. P. Duménil 1835; 40. and Pauline Bonaparte (1780–1825), Napoleon's sister, is reported to have used donkey milk for skin care. In France in the nineteenth century, Dr. Parrot of the Hospital des Enfants Assistés spread the practice of bringing motherless babies directly to the donkey's nipple (Bulletin de l’Académie de médicine, 1882). Donkey's milk was sold until the twentieth century to feed orphaned infants and to cure delicate children, the sick, and the elderly. For this reason, there were many donkey farms in Italy, Belgium, Germany, and Switzerland. In the twenty-first century, donkey milk is largely used in the manufacture of soaps and moisturizers, but evidence shows it has possible medical uses to treat infants and children with cow's milk protein allergy (CMPA) as a natural "formula" for infants.
Donkey milk production differs greatly from that of conventional dairy species, especially in terms of milk supply, which is much more limited. The equid mammary gland has a low capacity (max 2.5 L) and a part of the milk production should be left to the foal. Milking may be carried out two or three hours after separation from the foal.Doreau M (1991) Le lait de jument. INRA Productions Animales 4 :297–302. Donkeys should be milked three times a day from 20 to 90 days after foaling.Doreau M, Martin-Rosset W (2011) Animals that produce dairy foods – horse. In Encyclopaedia of dairy sciences (2nd ed.), Fuquay JW, Fox PF & McSweeney PLH, eds., San Diego, CA, USA: Academic Press, volume 1, pp. 358–364. A female produces between 0.5 and 1.3 litres of milk a day for about 6–7 months. The variability of donkey milk production is due to many factors, such as individual milkability, nutrition, genetics and management of reproduction, in addition to milking management.
Generally, a donkey farm for milk production is small, and has rarely more than ten heads or so. The largest donkey farm in Europe is found in northern Italy. The Montebaducco donkey farm in Quattro Castella, a comune in Emilia Romagna, Italy, has 800 donkey heads.
+ Composition of donkey's, mare's, human and cow's milk (g/100 g) |
6.6–6.8 |
3.1–3.8 |
3.5–3.9 |
4.4–4.9 |
12.5–13.0 |
2.46–2.80 |
0.55–0.70 |
0.1–0.19 |
77.23 |
17.54 |
5.23 |
The casein to whey protein ratio in donkey milk was lower compared to the value in cow milk.
Non-protein nitrogen (NPN) accounts for an average of 16% of total nitrogen in donkey milk, which is close to values reported for human milk (20%) but higher than those of domestic ruminants (5%).
The amino acid profile of the donkey milk proteins shows a very similar percentage of essential amino acids (36.7 to 38.2 g amino acid /100 g protein) than in human milk proteins (40.7 g amino acid /100 g protein).
In donkey mammary secretion, defatted or not, growth factors and hormones have also been determined. Donkey mammary secretions contain human-like leptin at levels close to human milk (3.35 e 5.32 ng/mL milk). The bioactive peptides insulin-like growth factor 1, ghrelin, and triiodothyronine were also found in frozen donkey milk. These molecules and many others present in human milk, are increasingly receiving attention from a nutraceutical point of view because of their potential direct role in regulating food intake, metabolism, and infant body condition.
In terms of energy, donkey milk has a high lactose content but a low average fat content. To use it in infant nutrition before weaning, donkey milk should be fortified with a source of fat (sunflower oil); particular attention must also be given to essential fatty acids. Omega‐3 and omega‐6 fatty acids, particularly docosahexaenoic acid (DHA), are known to play an essential role in the development of the brain and retina. Intakes in pregnancy and early life affect growth and cognitive performance later in childhood, ensuring adequate intakes of fat, essential fatty acids, and DHA through these life stages is crucial. Cost-effective dietary sources of these fatty acids are needed to ensure adequate essential fatty acid and DHA intakes in these populations. The integration of these substances can take place with supplements of essential fatty acids (omega-3; omega-6) and vegetable oil certified for babies. It is important to exclude spores that can pass the gastric mucosa in the first 4 months. For children who are not allergic to cow or goat milk, a part of the fat can be compensated naturally by adding 1–2% of cow or goat butter. In any case, the integration of fats and essential fats can be done through the integration of donkey milk with artificial formulas for infants.
From the point of view of hygienic-sanitary safety, like all milk, donkey milk and its ingredients must be pasteurized before taking. The process of pasteurizing donkey milk deactivates bacterial and viral contaminants.
Donkey milk contains immune-enhancing compounds (in particular lysozyme and lactoferrin) to help protect infants from disease. In addition, the flavour and appearance of donkey milk are attractive to children.
Raw milk can be kept for 3 days at refrigerator temperature starting from the day of milking. To prolong conservation, raw milk can be frozen for up to 2–3 months. In any case, it must be thawed in the refrigerator and pasteurized before use.
Analysis of freeze-dried donkey's milk has demonstrated that the natural colour, flavours, nutrients, and bioactive substances of fresh donkey milk are retained. Spray-drying is another way to dry products, in which the milk is heated and vitamins and other important bioactive substances may get lost. In contrast, Freeze-drying does not require chemical preservatives and can be either consumed directly or re-hydrated easily. However, this method for is costly, and is practiced only by a few companies.
This product is easy to find in Italy, where it was for the first time put on the market.
A recent scientific study on a cream containing lyophilized donkey milk showed different benefits for the skin. These results are related to the effectiveness of donkey milk components like proteins, minerals, vitamins, essential fatty acids, bioactive enzymes, and coenzymes which provide balanced nourishment and proper hydration for the skin. In particular vitamin C content in donkey milk is almost 4 times more of cow's milk. Since donkey milk contains more lactoferrin than cows milk, and a considerable amount of lysozyme, it has the potential, when properly formulated, to reduce skin problems such as eczema, acne, psoriasis, and herpes by calming the irritation symptoms as reported by some authors.
Some authors have preliminarily evaluated whether the use of a face cream made from donkey milk affected the perception of some sensory aspects. The results showed that treated cream was appreciated by dry skin consumers for the following sensory aspects: spreadability, total appearance, smoothness, moisturisation, and total effectiveness. The overall judgement also resulted highest for face cream made with donkey milk.
Donkey milk is used in the manufacture of soaps and creams. DonkeyMilkSoap.com A list of online shops selling donkey milk soap.
This was also the case for Poppaea Sabina (30–65), second wife of Roman Emperor Nero, who is referred to in Pliny's description of the virtues of ass milk for the skin:
"It is generally believed that ass milk effaces wrinkles in the face, renders the skin more delicate, and preserves its whiteness: and it is a well-known fact, that some women are in the habit of washing their face with it seven times daily, strictly observing that number. Poppaea, the wife of Emperor Nero, was the first to practice this; indeed, she had sitting baths, prepared solely with ass milk, for which purpose whole troops of she-asses used to attend her on her journeys."
In his poem Medicamina Faciei Femineae, Roman poet Ovid (43 BC–18 AD) suggests beauty masks made with donkey milk.
Pauline Bonaparte (1780–1825), Napoleon's sister, is reported to have used ass milk for her skin care.
Herodotus in the 5th century BC mentions it as a nutritious drink. Hippocrates (460–370 BC), the father of medicine, described the medicinal virtues of donkey milk. He prescribed donkey milk for numerous ailments, such as liver problems, edemas, nosebleeds, poisonings, infectious diseases, the healing of sores, and fevers. In Roman times, donkey milk was used as a universal remedy. Pliny the Elder (23–79 AD), in his encyclopedic work Naturalis Historia, described its many health benefits, ranging from its use as an anti-venom or as a relief for external irritations (itching) to the use of it in a pomade (ointment) for the eyes. He states that donkey milk is the most effective as a medicine, followed by cow's milk, and then goat's milk. During the Renaissance, donkey milk was the subject of the first real scientific consideration when Francis I, king of France, on the advice of his doctors, used donkey milk to recover from a long illness. There are many testimonials on the effectiveness of donkey milk. The French naturalist Georges-Louis Leclerc (1707–1788) underlined the benefits of donkey milk in his Histoire Naturelle.
Some effects have been supported by systematic and scientific studies starting from the mid-1800s, especially by Russian doctors.
Donkey and mare's milk are very similar, and it is assumed they have similar properties.
The beneficial effects of equid milk, from the first historical sources to the present day, are aimed at:
It was generally described as a food capable of regenerating a weakened, emaciated, impoverished organism in an unusually short time, allowing the body to achieve better resistance. It was used by the Asian (Mongolian) equestrian peoples often as the only source of food for long periods and during high physical exertion, without the body developing symptoms of deficiency. Under Genghis Khan, the Mongols established a large empire. They moved on their horses across the steppes, deserts, and mountains and covered large distances, and for long periods they lived mainly on the milk of their mares, both fresh and fermented (kumyss). Around 1850, various Russian doctors observed the habits of the shepherds of the Baskirian steppe. They reported that the Basic and Tatars spent the winter in very unfavorable environmental conditions, with temperatures down to minus 60 °C, severe winter storms, and very little or no food. Weakened nomads regained their strength unusually quickly as soon as they fed on mare's milk. Russian doctors observed in the 19th century that tuberculosis was practically non-existent among the steppe nomads. Doctors attributed it to fermented mare milk as the staple food of the steppe people. When this became known in Russia, a migration of tuberculosis patients from Russia to the steppes began. The treatment was initially "wild", without medical supervision. From 1850 the first sanatoriums were founded and treatments were oriented along systematic, medical-scientific lines, however, the importance of kumyss treatment of tuberculosis in Russia lasted until about 1970, then it was gradually replaced by modern medicine. However, Kumys' treatment was the most effective tuberculosis therapy for many years. Treatment with kumyss & mare's milk has been extended to many other diseases in Russia and Kazakhstan over the decades. Language barriers and cultural differences still prevent exchange between the Western cultural area and these cultures today, however, Russia and Kazakhstan are still conducting scientific research on the effects of equine milk and kumyss on humans.
Postnikov, a Russian doctor who dedicated his career to the research and use of horse milk in the mid-19th century, summed up its effects in three words:
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