A new study by Newcastle University proves that organic farmers who let
their cows graze as nature intended are producing better quality milk.
Nafferton Ecological Farming Group study found that grazing cows on
organic farms in the UK produce milk which contains significantly
higher beneficial fatty acids, antioxidants and vitamins than their
conventional ‘high input’ counterparts.
fats in particular – conjugated linoleic acid, or CLA9 – was found to
be 60% higher.
The results of this study into UK dairy production are published online in the Journal of Science of Food and Agriculture.
have known for some time that what cows are fed has a big influence on
milk quality,’ explained Gillian Butler, livestock project manager for
the Nafferton Ecological Farming Group at Newcastle University, who led
the study. ‘What is different about this research is 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.
that significant seasonal differences exist, with nutritionally
desirable fatty acids and antioxidants being highest during the summer,
when the cows are eating fresh grass and clover.
‘As a result,
our future research is focusing on how to improve the nutritional
composition of milk during the winter, when cows are kept indoors and
fed mainly on conserved forage.’
The study, which involved
Newcastle scientists working with the Danish Institute for Agricultural
Science, is part of the ongoing cross-European Quality Low Input Food
project into animal health and welfare, milk quality and working
towards minimising the use of antibiotics in dairy production.
paper is a major milestone in the project and clearly shows that if you
manage livestock naturally then it’s a win-win situation for both us
and them,’ said Professor Carlo Leifert, project co-ordinator.
scientists also discovered interesting results from a group of
low-input farms in Wales, which are not certified organic but use very
similar production methods to organic farms (the main difference was
the use of some mineral fertiliser and shorter withdrawal periods after
To reduce costs, these farmers calved all their
cows in spring and grazed them throughout lactation, from March until
November, resulting in milk being produced on an almost 100% fresh
Milk from these non-organic farms also had
significantly higher levels of nutritionally desirable fatty acids and
antioxidants, which was a direct result of the extensive outdoor
rearing and fresh forage intake.
‘These New-Zealand type dairy
systems are not common in the UK, as weather conditions in many areas
of the country make it unworkable,’ explained Mrs Butler. ‘Therefore,
milk from these farms is not available to the public as it’s mixed in
with milk from conventional systems during processing.
including these extremely extensive systems allowed us to clearly link
the difference in milk quality to the dairy cows’ diets.’
Tweddle, of Acorn Dairy in County Durham, is a local supplier of
organic milk. ‘We have believed for some time that organic milk is
better for us and our customers tell us it tastes better,’ he said. ‘It
is satisfying to have the scientific explanation as to why it is also
This current research confirms previous
studies in the UK, which reported higher concentrations of omega 3
fatty acids in milk from organic production systems than conventional
CLA, omega-3 fatty acids, vitamin E and carotenoids have
all been linked to a reduced risk of cardiovascular disease and cancer.
CLA is hugely popular in the US, where it is marketed as a nutritional
supplement. However, synthetic supplements often contain compounds with
a different chemical composition (isomer balance) than those occurring
naturally in milk, resulting in an equal dose of both ‘good’ (i.e.
CLA9, omega-3 fatty acid, vitamin E and carotenoids) and ‘less
desirable’ fatty acids (i.e. omega-6 fatty acids and CLA10).
to organic milk provides an alternative, natural way to increase our
intake of nutritionally desirable fatty acids, vitamins and
antioxidants without increasing our intake of less desirable fatty
acids and synthetic forms of vitamin E,’ said Mrs Butler. ‘In organic
milk, the omega-3 levels increase but the omega-6 does not, which helps
to improve the crucial ratio between the two.’
involved 25 farms across the UK in two contrasting areas of the UK –
South Wales and the North East. The scientists looked at three
different farming systems: conventional high input, organically
certified, and non-organic sustainable (low-input).
Nafferton Ecological Farming Group at Newcastle University collected
109 milk samples from 25 commercial farms categorised into the three
different production systems: conventional high input; organically
certified low input; and non-organic, low input. These samples were
taken in August and October in 2004 and January, March and May the
The group investigated the effects of seasonal
and indoor/outdoor feeding differences on the milk’s fatty acid
profile, and also compared individual carotenoids, stereo-isomers of
alpha-tocopherol (vitamin E) or isomers of CLA. The higher levels of
nutritionally desirable fatty acids found in the organic milk were
CLA9, omega-3 and linolenic acid and the antioxidants/vitamins were
vitamin E and carotenoids. The lower levels of undesirable fatty acids
were omega-6 and CLA10.
Newcastle University. May 2008.