19 June 2009

3 minute read

Europe

How can obesity in older women, lucerne and grass, breast cancer and the keeping qualities of milk have anything in common? They can at the Faculty of Agricultural Sciences at Aarhus University, where cows from one experiment will deliver milk for three other completely different experiments, writes Janne Hansen, Faculty of Agricultural Sciences, Aarhus University. The suppliers of milk for the different projects are organic cows that are part of an experiment into how milk yield and milk content of vitamins and minerals can be optimised.

"On the one hand, we would like cows to have a high milk yield, but on the other we would also like the milk to be healthy," says senior scientist Søren Krogh Jensen from the Faculty of Agricultural Sciences, who is in charge of the cattle experiment funded by the Ministry of Food, Agriculture and Fisheries.

Green and white milk

In the cattle experiment the cows were divided into two groups. In the group producing the so-called ‘white’ milk, scientists tested which type of organic feed (e.g. concentrate and maize silage) would give a high milk yield. This type of feed normally produces milk rich in energy but poor in vitamins and minerals.

With the group of cattle producing ‘green’ milk, scientists tested how cows’ vitamin and mineral requirements could be met from natural sources (i.e. with no additions of vitamin and mineral mixtures) without too adverse an impact on milk yield. The feed in this group was mainly roughage. Vitamin sources were grass-clover and lucerne while minerals came from different herbs, such as chicory and plantain. The grass was moreover harvested earlier than normal to maintain a high vitamin and energy level.

"Meeting the cows’ requirements from purely natural sources was completely in line with the best organic principles," says Søren Krogh Jensen.

The two experiments produced similar milk yields, but the milk was completely different. It differed in fatty acid composition, vitamin and mineral contents and in bioactive components – and was therefore extremely interesting for other scientists.

Milk in other experiments

Bioactive phyto-oestrogens in the ‘green’ milk are exactly what scientists are looking at in another experiment. These compounds alleviate osteoporosis, reduce cholesterol levels, and may also reduce the risk of contracting breast and prostate cancer.

In another experiment with scientists from KU-Life, the taste and keeping qualities of both the ‘green’ and ‘white’ milk are being tested.

And in a third experiment carried out at the Department of Human Nutrition at University of Copenhagen, scientists are studying whether the milk fat of the two milk types have an effect on fat burn in obese, older women. The women taking part in the experiment receive ‘green’ and ‘white’ milk in the form of purpose-made butter and cheese from Thise Dairy.

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