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Overview of Milk of Non-Bovine Mammals (Second Edition)

Young W. Park,1 George F.W. Haenlein,2 and W.L. Wendorff 3

1 Agricultural Research Station, Fort Valley State University, Fort Valley, GA, USA

2 Department of Animal and Food Sciences, University of Delaware, Newark, DE, USA

3 Department of Food Science, University of Wisconsin-Madison, Madison, WI, USA

1 Introduction

The First Edition of Handbook of Milk of Non-Bovine Mammals, compiled information on the availability, composition, and technology of milk produced from domestic non-bovine mammals throughout the world, has been a success, so much so that it has been translated into two additional languages, Spanish and Chinese. Therefore, a Second Edition has been recommended by Blackwell-Wiley Publishers. We welcome the addition of W.L. Wendorff to the editor team, who is an international authority on cheese technology and dairy sheep besides representing the leading US dairy state Wisconsin. We also welcome several new expert co-author contributors: Mariana Marques de Almeida from Portugal, Golfo Moatso from Greece, Samir Kalit from Croatia, Elizabetta Salimei from Italy, Ying Ma and Shenghua He from China, Leorges M. Fonseca from Brazil, Benedicte Coude from France, Mian Murtaza from Pakistan, Shane Crowley from Ireland, David Thomas, John Lucey, Mark A. Johnson, and Pat Polowsky from Wisconsin, USA.

The First Edition of Handbook of Milk of Non-Bovine Mammals, published in 2006, covered the eight domestic non-bovine milk-producing species: goats, sheep, buffalo, mare, camel, yak, reindeer, human, as well as sow, llama, and other minor species. This Second Edition, after reviewing and updating the First Edition has added the milk of donkeys, zebu, and mithun species. Since 2006 much new information from research with these species has become available and two significant new publications from the international Food and Agriculture Organization in Rome, Italy (Kukovics, 2016; Muehlhoff, Bennett, and McMahon, 2013), have added emphasis on the importance of non-bovine domestic species for providing people in areas of difficult climate and geological conditions with essential nutrition and sustainance. "There is huge scope for developing other dairy species . and that alpaca, donkey, moose, reindeer and yak milk should be used to counteract high cow milk prices ." in the developing world (Muehlhoff, Bennett, and McMahon, 2013) has been stated in this latest authoritative FAO publication.

Dairy goats in particular have led in increasing numbers (66% during the last 20 years worldwide versus 14% for dairy cattle), because they are profitable for poor households by valorizing low quality forage, tolerate water shortage, and enhance rangeland biodiversity (Kukovics, 2016). Non-bovine commercial dairy products mean the reality that in many parts of the world the Western ideal milk-producing cow needs help from other domestic mammals, which are better adapted to adverse conditions of climate and geological environmental conditions. The knowledge of their productivity and composition of their products has not been published much in the Western world and non-Western scientists working with these mammals have not been heard much in the English literature. This Handbook, however, aspires to amend this situation by focusing on these other important milk-producing domestic mammals, the value of their products, and their future potential. As the FAO book stated, "there is huge scope for developing other dairy species ." (Muehlhoff, Bennett, and McMahon, 2013).

It has also been learnt that the Nordic countries, Norway, Denmark, Sweden, Finland, Iceland, and Greenland have invested $112 million for 2015-2018 in four new interdisciplinary Centers of Excellence to improve and develop animal products more and better for human nutrition and health in those adverse arctic regions of the world in order to sustain their human populations (Nordforsk, 2005). This is in addition to a research program by the University of Alaska at Fairbanks with reindeer in cooperation with the California Polytechnic Institute (Alaska, 2014).

As consumers in modern societies are seeking for diversified, sophisticated, and nutritious foods, more and more people in developing and developed countries have an interest in knowing about the composition and constituents in dairy products as they relate to human health (Campbell and Marshall, 1975; Smith, 1985; Park and Haenlein, 2006). Not many people paid much attention or knew much about good and bad types of fat and fatty acids until recently. Today's nutrition labels on food products indicate levels not only of protein, fat, carbohydrates, sodium, calcium, and vitamins but also of such special ingredients as saturated, unsaturated, omega-3, conjugated, and trans-fatty acids. This open knowledge leads to interest into which dairy products may be superior to others and which animal feeding system, such as pasturing versus barn feeding, or which animal species produces a more suitable or preferable human food to others. In terms of milk for infants or sick patients, they need to know which milk is closest to human milk and best for babies, which milk creates less allergies, which one is better tolerated by people with gastrointestinal ailments, which dairy product causes no lactose intolerance symptoms, or which species of milk and dairy products have better digestibility (Park and Haenlein, 2006).

2 Evolution of the Bovine and Non-bovine Dairy Industry

Throughout history, in search of socioeconomically feasible and nutritionally superior sources of food, man has domesticated some milk-producing dairy species, and selected and bred them to produce large volumes of milk in excess of the necessary amounts needed to nourish the animal's own offspring. This surplus production of milk beyond nourishing the young has become the foundation of the modern dairy industry. In North America, Europe, Australia, and New Zealand, the dairy industry is one of the most integral enterprises and important national economies among all agricultural production businesses (Park and Haenlein, 2006).

Even though the dairy cow has been the predominant domesticated animal species for dairy production in developed countries, the goat, sheep, water buffalo, yak, camel, mare, reindeer, as well as some other minor mammalian species have been domesticated, kept, and bred for milk production in regions of the world where the difficult environment required special adaptation, and for which many of the non-bovine mammals are better suited (Park and Haenlein, 2006).

The knowledge on anatomy, histology, physiology, and biochemistry of milk component synthesis and their secretory processes in the mammary gland is essential for the efficient production, maintenance, and utilization of milk for human consumption. Greater understanding of this will provide dairy producers with the integral and necessary capacity to improve management and environmental conditions of their dairy animals for higher efficiency, greater quality, and larger volumes of milk production. Such knowledge would also give dairy producers opportunities for affecting the composition of milk to meet more functionally the nutrition and health needs of people (Park and Haenlein, 2006).

Milk is one of the most nutritious natural foods and has been a basic component of the human diet since early history. Milk drawn from the lacteal glands is highly perishable and is adversely affected by improper practices of feeding and handling of the animals, handling of milk during and after milking, cooling, transportation, pasteurization, processing, packaging, processing equipment, and storage (Le Jaouen, 1987; Peters, 1990; Park, 2010). Through understanding of the basic science of lactation in domesticated mammals, the milk production volume and quality can be maximized for effective utilization and processing of milk products for human consumption.

Western animal science has demonstrated and developed tremendous genetic resources in dairy cows; where 50 years ago they produced about 12 kg of milk per day today many have evolved through genetic selection to produce 50 kg of milk per day. Likewise Western dairy sheep and dairy goats have evolved from producing 1 kg of milk per day to as much as 10 kg of milk per day during the last 50 years (Haenlein, 2007). This is the challenge to the developing world dairy science to which this Handbook wants to help catch up with the most up-to-date knowledge and to recognize scientists in the developing world. Overall there are three major challenges facing progress in non-bovine dairying:

1. The size and metabolic activity of the mammary gland must increase through genetic selection, especially in mares, donkeys, camels, and reindeer.
2. The size of the teats and their placement on the udder must become more practical for manual and machine milking procedures, especially in dairy sheep.
3. The milk let-down reflex via the oxytocin hormone release must become habituated to the human presence and their stimulation without the need to have a calf or foal present.

3 Composition and Secretion of Milk of Minor Species

The milk composition data of at least 194 mammalian species have been identified in a comprehensive review (Oftedal, 1984), while relatively few studies on non-domestic species were found to...