Cows' natural diet puts us all in clover; Organic milk is most heathy.

Byline: Tony Henderson Environment Editor

COWS which eat the diet nature intended produce better quality milk, a study has shown.

The work by Newcastle University has proved that organic farmers who allow their cows to graze mostly on fresh grass and clover in summer end up with milk which is more beneficial health-wise for people.

The Nafferton Ecological Farming Group, based in the Tyne Valley near Corbridge in Northumberland, found that grazing cows on organic farms produced milk which contains significantly higher beneficial fatty acids, antioxidants and vitamins than animals on a conventional diet.

On the conventional diet, cows ate one third grazed grass, one third silage, or "conserved" grass and one third cereal-based food. The diet of the organic animals was 80% fresh grass and 10% each of silage and cereals.

During the summer months, one of the beneficial fats in particular - conjugated linoleic acid, or CLA9 - was found to be 60% higher in the organic cows' milk.

CLA and omega-3 fatty acids have been linked to a reduced risk of heart disease and cancer.

Gillian Butler, livestock project manager at Nafferton, who led the study, said yesterday that the digestive systems of cattle had evolved to deal with a forage-based diet and that there could be negative impacts by interfering with nature.

"The components from fresh grass get translated into better health benefits for us," she said.

"We have known for some time that what cows are fed has a big influence on milk quality.

"What is different about this research is that it clearly shows that on organic farms, letting cows graze naturally, using forage-based diet, is the most important reason for the differences in the composition between organic and conventional milk."

She said that the "conventional" silagecereals-grass diet was fed to cows to increase milk yield.

On the conventional diet, cows produced an average of 26 litres of milk a day while the organic option resulted in 18.4 litres.

"If you want cows to produce more milk you have to feed them more, but the milk is not as good in terms of beneficial components."

The aim was now to use the results of the diet study to improve the quality of milk across the board and how to better the nutritional composition of milk during the winter, when cows are kept indoors and fed mainly on silage.

The study, which involved Newcastle scientists working with the Danish Institute for Agricultural Science, is part of a European project into animal health and welfare, milk quality and working towards minimising the use of antibiotics in dairy production.

GLAD TO BE RIGHT

ONE of the farms in the study is run by Gordon and Linda Tweddle in County Durham, whose family have been farming at Archdeacon Newton for four generations.

Gordon and Linda converted their Garthorne Farm to organic status. Their Acorn Dairy business is now reviving the tradition of doorstep delivery with their own organic milk and cream.

Gordon said: "We have believed for some time that organic milk is better for us and our customers tell us it tastes better. It is satisfying to have the scientific explanation as to why it is also nutritionally better."

CAPTION(S):

FRESH The quality of the milk we drink is directly linked to a cow's diet.; FOOD FACTS Gillian Butler, livestock project manager at Nafferton.