Milk flavour starts in the cow pasture

The first steps towards making designer milk are being taken by scientists who are investigating if you can control milk flavour by controlling the composition of the cow pasture.

How about a glass of chicory milk? Or what do you say to a bowl of clover ice cream? In the not-so-distant future it may be that consumers can choose dairy products with naturally different taste variations because the cows have been fed “to flavour”.

Scientists from the Faculty of Agricultural Sciences (DJF) at University of Aarhus have worked together with scientists from the Faculty of Life Sciences at University of Copenhagen (KU-LIFE) in order to investigate the effects of different pasture mixtures on the taste of organic milk. One of the goals was to be able to offer an organic product that differentiates itself from conventionally produced milk.

Milk flavour depends on a number of factors. By gaining a greater understanding of the relevant factors it can be possible to control them and thereby the milk’s flavour. The end result could be milk and other dairy products that are tailormade to suit the consumer’s personal taste buds.

The first results show that it is possible to feed cows to produce milk with different tastes by using different pasture mixtures but that it is difficult to predict the results.

"You can measure aromatic compounds in the crops but that is not the same as being able to predict what goes into the milk. That is because the cow is a ruminant," says senior scientist Troels Kristensen from the Department of Agroecology and Environment at the Faculty of Agricultural Sciences, University of Aarhus.

Grass effect passes through the rumen

Milk flavour is already affected in the cow’s rumen. The composition of the bacteria in the rumen exerts a great influence on milk flavour due to the metabolites of the bacteria. The combinations of rumen bacteria and their metabolites depend partly on what the cow eats. In that way the pasture affects milk flavour.

The scientists have studied the effect of four different pasture mixtures on milk composition and taste as well as milk yield. In the grazing studies some pasture mixtures included relatively high levels of various legumes (white clover, red clover and alfalfa) and chicory. The study was divided into three periods of 14 days in May, June and August.

Neither milk protein composition, milk fat composition nor milk yield were significantly affected, but there were taste differences in milk from different pasture mixtures and different periods. Observations of pasture development and cow grazing behaviour were also included in the study. It was seen that the cows were somewhat picky eaters, which resulted in selective and heterogenous grazing.

The next step is to try and produce a stable product that is predictable and does not vary according to season.
The scientists will also test if the method can be used under practical conditions and are therefore carrying out studies on six different practical organic farms with varying proportions of white clover.