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Cattle have been domesticated since the Neolithic Age, but did Stone Age farmers select their cattle? And what about the thousands of years between first domestication and the modern era, how much selection has taken place? In a newly published study, Utsunomiya and colleagues have brought together cattle genetic data from around the world to reveal those regions of the genome that light up with the hallmarks of selection.

One cell, all by itself, can make milk. A single cell makes a very tiny amount, however, while more of them working together make a copious supply (or so we hope). That some mothers are not able to make enough milk is exactly what motivated scientists at Cincinnati Children’s Hospital Medical Center and University of California, Davis to determine what genes are turned “on” to make milk.

The placenta and the mammary gland may be separate organs, but they are better viewed as part of a coordinated team, charged with transferring nutrients, immune factors, and other bioactive components to the developing offspring. The placenta manages the first 40 weeks, but if the baby is born prematurely (<37 weeks gestation), the mammary gland works overtime to produce milk with higher concentrations of components that should have come from the placenta.

Milk is a wonderfully complex fluid that is not only nutritious but is also physiologically proactive. Recently, David Dallas and his colleagues from University of California at Davis used a cutting-edge approach to probe the depths of milk composition. The initial results revealed that human breast milk contains proteins which are digested into peptides, some with antibacterial properties.

Working out means losing liquid, for some of us more than others. The lost liquid needs to be replaced, particularly if you intend to exercise more on the same day. A whole industry has been built around creating sports drinks to rehydrate athletes—and those of us who can only dream of becoming athletes—quickly and effectively. But for all these branded drinks’ isotonic technicalities, hyperactive coloring, and celebrity sponsorship deals, they tend to come second on rehydration tests behind humble, old milk!

Weaning in primates is a fascinating process in which ingestion of mother’s milk, as a proportion of daily dietary intake, incrementally declines as the infant ages. From moment to moment, this exquisite negotiation of nipple access between mother and infant can vary in relation to food availability, maternal style, and the compelling power of the infant demand (a.k.a. weaning tantrum). And lots of other factors can influence the weaning process, too.

Allomaternal nursing, the practice of infants suckling from a female not their mother, takes many forms. This behavior is not unique to humans and is widespread among mammalian species. Allomaternal nursing is thought to increase the fitness of females and infants, which would be favored by natural selection, but little research effort is directed to the topic. More recently, modern technologies of plastic containers, cold storage, and rapid shipping have created opportunities for milk sharing and milk selling widely among women. Some researchers and clinicians consider this unregulated trade of human milk a cause for concern–especially the risk of disease and toxin transmission to developing babies. Before that, though, let’s consider allomaternal nursing through historical,

Dairy farmers everywhere would rejoice if scientists discovered a way to breed cows that continually produce milk. The answer to this biological riddle may lie in the study of other milk-producing animals. Weird animals produce milk with various lactation strategies. Some produce all of their milk in just a couple days while others produce milk over five years. Some produce copious amounts of milk for a couple days and then not again for several weeks. By comparing the lactation strategies of different animals, researchers can identify exciting new methods of milk production.

Wouldn’t it be great if there were a nontoxic cancer treatment that effectively killed tumor cells without causing any harm to healthy cells in the patient’s body? Or how about a chemical that could make antibiotics effective against bacterial strains that have become antibiotic resistant, such as pneumococci or MRSA (methicillin-resistant Staphylococcus aureus)? Solving just one of these tasks would be a medical miracle, and yet a team of American and Swedish researchers has shown that both are possible. Even more amazing is that the solution to these two seemingly disparate medical issues comes from the same molecule, a protein-lipid complex found in human breast milk called HAMLET (human alpha-lactalbumin made lethal

Pick up any textbook that runs through the sugars in milk, and you will read that human milk is unusual. It contains more oligosaccharides (medium-length sugars) than the milk of other mammals, and, in particular, most of its oligosaccharides have some subunits of fucose, a small sugar. Farmyard mammals, in contrast, do not make oligos out of fucose. At least, that was the conventional wisdom. But the distinction is now invalid.

Milk has evolved to sustain life through supporting the growth and healthy development of infants. A recent article in the prestigious journal Science reported a breakthrough in our understanding of what lies behind the cellular mechanism of the growth “switch”.

Type 2 diabetes describes a condition where cells that would normally respond to insulin by absorbing glucose from the blood stop doing so, allowing blood glucose to rise to unhealthy levels. It is closely associated with obesity. Various studies link the regular consumption of low-fat dairy products to reduced odds of developing type 2 diabetes. Not every study finds this effect, but in those that do, the question is: why?

‘Slow down, Mama!’ In contrast to breastfeeding, which allows infants to feed on demand, bottle feeding enables parents to provide set volumes of milk to babies. Latest evidence shows that breastfed babies control their appetite better than formula-fed babies, and although the mechanisms through which this occurs are not yet clear, it has been shown that this has long-term effects on appetite regulation and weight control into adulthood. Perhaps it is time to start seriously considering breastfeeding as an intervention window against the obesity epidemic.

Does dairy make you fat? Being rich in lipids, it should, right? But some evidence suggests that the calories in dairy are somehow easier to burn up than they should be. While the effect is subtle (and certainly not apparent in every set of data), it is sufficient for physiologists to wonder about potential biochemical explanations.

The production of milk by the mammary gland is a key adaptation of mammals. But simply producing the milk is not enough; that milk needs to get from the mammary gland to the nipple to be ingested by the infant. But how is this movement of milk accomplished? An amazing hormone called oxytocin. How did oxytocin, and therefore milk letdown, it evolve?

The list of proteins in cow’s milk just keeps getting longer. Tim Reinhardt and colleagues have now discovered nearly 3000 unique proteins in cow’s milk (1). While that would be a story by itself, they also reveal evidence for web-like nets that immune cells secrete into milk when pathogens are present. Yes, milk is cooler than fiction.

Milk enthusiasts probably all share a favorite bacterium: Bifidobacterium infantis, the species that coevolved with humans and promotes a healthy infant gut. Breast milk contains many other kinds of bacteria, but recording the full species register is a surprisingly tricky task. Recently, a team of Swiss researchers did the most complete job yet.

The last time I read Mary Roach was on holiday, in the evenings that followed long hikes up, along, and down tabletop mountains in southern Venezuela. I read aloud from Stiff: The Curious Lives of Human Cadavers because my tent buddy was too careful a packer to have allowed himself the additional mass of a book. As he sensibly tended to sore blisters and swollen bites, I enriched the moment by, for example, loudly vocalizing Roach’s prose about the precise details of how and when death occurs in people who are unlucky enough find themselves inside planes that explode in the sky. This time I’m digesting Gulp: Adventures on the Alimentary Canal in the tearoom of the University

Babies are well protected and nourished while still in the mother’s womb, but what happens after they are born when they are suddenly exposed to a challenging environment full of new and invasive bugs? The mother steps in again by providing breast milk. This magical dynamic fluid contains not only the necessary nutrients for the optimal growth of the infant, but also activated immune cells. Two breakthrough studies show that these immune cells selectively migrate into colostrum and milk.

Last month in SPLASH!, we learned that early life conditions can influence a cow’s future milk production (see Katie Hinde’s article). But how does this happen? Why does the amount of energy available to a female fetus or calf influence how much milk her mammary gland produces later in life?

In a world filled with harmful bacteria, viruses, and parasites, it seems quite paradoxical that a human infant would be born with an immature and inefficient immune system. That is, of course, until you realize the infant benefits from mom’s immune system hard at work in mucosal surfaces. The process of transferring immunity, also known as passive immunity, begins during pregnancy with the transfer of Immunglobulin G (IgG) cells from maternal to fetal circulation through the placenta. At birth, the mammary gland takes over, providing numerous types of immunogloblulins (antibodies) and other immune factors.

For many years, researchers have known that breastfed infants gain some protection from certain viral infections. Occasionally, however, viruses like HIV, a kind of herpes called cytomegalovirus, and HTLV-1, which is linked to leukemia, are transmitted in breast milk from mom to babe. Explaining why infection occurs in some mother-infant pairs but not in many others remains a pressing question. Lately, a series of papers has implicated the complex and highly variable jumble of carbohydrates found in breast milk. In most cases these appear to protect infants from viral infection. But, on rare occasions, they may facilitate it.

Maternal nutritional conditions during pregnancy are known to have substantial impacts on infant development. This was most clearly demonstrated by research into the outcomes of infants from the Dutch Hunger Winter of 1944. Because determination and differentiation of cell lines occur during embryonic development, nutritional conditions and other environmental insults early during pregnancy can substantially alter offspring phenotype, including behavior and general health.

With the development of genomic tools for dairy cows, what value do studies of lactation genomics in mice and other animals hold for dairy innovation? A recent study reported in the January 2013 issue of Physiological Genomics is the latest in a series of studies of lactation in mice that have involved scientists affiliated with the IMGC.