You know the slogan “milk does a body good.” But amid new research, scientists might soon be able to tell you how and why – then produce better milk.
Researchers at UC Davis, among others around the country, published a study on Apr. 24 that marks the end of an initial 18-month scientific effort, but the beginning of what some believe might lead to healthier, cheaper and more ecologically friendly milk.
The paper outlines the portion of genes – a combination of chemical “letters” that code for physical traits – of the genome (the complete set of instructions for all biological processes) that is responsible for milk and milk production in cattle as well as six other species of mammals.
The study, “The Bovine Lactation Genome: Insights into the Evolution of Mammalian Milk,” coordinated with the milestone publication of the entire cattle genome sequence – research that involved 300 scientists in 25 countries.
The sequencing of the cattle genome will now allow scientists to better identify the constituents of cow milk and further understand the similarities and differences between it and human milk, said Dr. Monique Rijnkels, assistant professor of the department of pediatrics at Baylor College of Medicine, in an e-mail interview.
The bovine lactation genome study identified 197 milk-protein genes and at least 6,000 milk production genes within the cattle genome.
Researchers examined cattle, human, dog, mouse, rat, opossum and platypus data for an understanding of species-specific milk and milk production strategies. Scientists found that milk secretion proteins remained very similar across species, but the nutritional components of milk diverged significantly from species to species, shedding light on the evolution of milk and lactation.
“Milk is the only food that has evolved specifically to provide nutrition and health to growing mammals,” said Dr. Juan Medrano, professor of animal genetics with the UC Davis department of animal science, in an e-mail interview.
“We can now better learn how milk and its components specifically affect the healthy development of babies and how it can also serve as healthy food for adults,” Rijnkels said.
The availability of the cattle genome sequence and the identification of the milk and milk production genes will not only provide better information about its properties, but scientists will now be able to identify ways in which milk can be better tailored for human consumption, said Danielle Lemay, lead author of the milk genomics study and bioinformatician and nutrition scientist with the UC Davis department of food science and technology, in an e-mail interview.
“We may be able to select cattle with enhanced qualities to produce milks, for example, with more desirable carbohydrates to be used in infant formulas to better stimulate immune function, to produce milks with a higher content of healthy fats that might provide cancer protective properties and to increase the protein content in milks,” Medrano said.
Improvements to the selection of cattle might not only enhance milk nutrition, it may also improve milk production.
“We may be able to decrease the impact of raising dairy cows by selecting for healthier animals, improving feed efficiency, getting more milk from fewer cows, and reducing greenhouse gases,” Lemay said. “Today’s farmer may determine the breeding value of a bull by breeding that bull 500 times. But tomorrow’s farmer will need only a blood sample and a genotype chip.“
DAVID LAVINE can be reached at features@theaggie.org.
