Milk is Not Just Milk

Scientists are endeavouring to combine knowledge of the composition of milk with knowledge of the natural variation in the cow's inherited traits. The aim is to be able to select cows on the basis of specific milk qualities.

The future will probably not give us milkshakes or yoghurt straight from the udder. And yet - perhaps a new Danish-Swedish research project that will be launched at the Faculty of Agricultural Sciences, Aarhus University, will in the future make it easier for the farmer to identify the cows that produce milk specifically suited to, say, cheese production or with a particularly healthy fatty acid composition.

Milk and genetics

Scientists from the Faculty of Agricultural Sciences are taking part in a comprehensive Danish-Swedish project that aims at identifying genetic differences in the nutritional, health, and technological properties of milk. By combining new "omics" techniques - genomics, proteomics and metabonomics - scientists will link the differences in the genetic make-up of the cow with differences in the composition and qualities of the milk.

The aim is to clarify how genetics affect the technological properties of milk and its nutritional and health profile. When scientists have identified the variations, they will identify genetic markers that can help the farmer select the cows that produce specific types of milk.

A total of 1600 SDM and Jersey cows from Denmark and Sweden will form the backbone of the extensive experiments that are a collaboration between the Faculty of Agricultural Sciences, the Danish Cattle Federation and Arla Foods and also Swedish partners. The cows that are not closely related will deliver milk and blood samples for the investigations.

The milk will be tested for selected properties, including its ability to coagulate (which affects its cheese-making qualities), its composition right down to the molecular level and its health qualities. The animals will also have their genetic profile mapped.

"There are large individual differences in terms of milk properties. With these investigations we will get a sort of fingerprint of each animal", says senior scientist Lotte Bach Larsen from the Department of Food Science at the Faculty of Agricultural Sciences, and who leads the large project.

With a total budget of DKK 24 million, 12.7 of these from the Programme Commission on Health, Food and Welfare, the four-year project is so far the largest in the Department of Food Science. The department of Genetics and Biotechnology at the Faculty of Agricultural Sciences also participates in the project.

Milk genomics

Milk genomics is a relatively new research area that comprises identification and characterisation of natural genetic variations in the cow that are expressed as different functional and nutritional traits through changes in milk composition.

The quality traits of the milk often have a very complex background and are controlled by a combination of several genes. With the increased knowledge of the cattle genome, there are good opportunities for identifying cows that produce milk with a specific composition and functional traits.