The production of milk from horses and donkeys could develop into a promising extension of the equine industry, according to researchers.
Equine milk products are consumed by an estimated 30 million people worldwide, Nicoletta Miraglia, Elisabetta Salimei and Francesco Fantuz reported in a review published in the open-access journal Animals.
Even so, consumer recognition of equine milk and its derivatives remain limited.
This emerging niche market, they say, raises questions on appropriate management strategies for mares and foals, mainly related to nutrition, environmental issues, food security and animal welfare.
Miraglia and her colleagues set about reviewing available scientific literature on the key issues around equine milk production.
The trio noted that the nutritional and therapeutic peculiarities of equine milk have been known since ancient times, and were described by Hippocrates and Herodotus in the 5th century BC.
In Central Asia, the consumption of the traditional drink koumiss, or airag, is considered a popular remedy for a variety of diseases. The traditional use of donkey milk is also reported in China and South America for the treatment of many illnesses.
Recent scientific findings on the composition of equine milk and its potential health-promoting properties have increased interest toward its use for human consumption, they say, especially for sensitive consumers such as children with allergies to cow’s milk protein, as well as immunocompromised or debilitated people.
Horse and donkey milk are closer to human milk in terms of both protein and lactose content than cow’s milk. However, as a food for infants, it does not have enough calories and requires supplementation.
The review team traversed a wide range of properties identified in equine milk, including a range of bioactive compounds, which point to the desirability of equine milk.
They say milk yield is affected by many factors, including farming systems, nutrition, feeding strategies and the type of milking, individual milkability, the stage of lactation, the size and body condition of the animals, and genetics.
The core of the dairy equine enterprise shows important differences from conventional dairy species.
Firstly, dams and foals live together until weaning, which occurs at seven months or later. The mothers won’t start to be milked until 20 days after foaling.
Since the equine mammary gland is characterized by small volume, milk harvesting can be carried out many times a day. In the steppes of Central Asia, mares are milked 4 to 5 times a day. In more intensive dairy farms located in Europe, mares and jennies are frequently milked, depending on consumer demand, up to eight times a day.
Milking is carried out at least 2 hours after foal separation from the mother.
“It must be noted that milk ejection is not reported to be affected by the presence of the foal during milking in the dairy donkey farm, while it is recommended in the dairy horse farm for a complete oxytocin release.
“In this regard, the selection for milkability of mares would greatly improve the milking routine, reducing the labor costs.”
Milk harvested per milking session is reported to range within 500ml to 2000ml for mares, and 200m to 900ml for jennies.
In intensive farming systems, adapted sheep milking machines are used.
In Italy, the price of donkey milk ranges from €9 to €15 per litre of raw milk, and €14 to €17.5 per litre for pasteurized milk. Powered milk is €27.5 to €36 per 100 grams. No prices were given for mare’s milk.
The authors went on to explore animal management, concluding that in-depth studies are still required, especially in terms of nutrition and feeding.
“A better understanding of nutrient requirements of the dairy equid at pasture in heterogeneous and marginal areas will boost the interest toward endangered equine breeds, their milk, and their habitat,” they said.
“Among the innovations for sustainable agriculture, the production of equine milk and derivatives with high nutritional value and health-promoting properties should be therefore considered a promising extension of the equine industry for the modern and future society.”
Miraglia and Salimei are with the University of Molise; Fantuz is with the University of Camerino
Miraglia, N.; Salimei, E.; Fantuz, F. Equine Milk Production and Valorization of Marginal Areas—A Review. Animals 2020, 10, 353.