Verification of fresh grass feeding, pasture grazing and organic farming by cows farm milk fatty acid profile

The present study investigated the use of fatty acid (FA) profiling in combination with chemometric modelling to verify claims for cow milk in terms of fresh grass feeding, pasture grazing and organic/biodynamic farming. The FA profile was determined for 113 tank milk samples collected in the Netherlands from 30 farms over four different months, and used to develop classification models based on the PLS-DA algorithm. Milk from cows with daily rations of fresh grass could be successfully distinguished from milk from cows with no fresh grass in their diet. Milk from cows at pasture could easily be distinguished from milk from stabled cows without fresh grass in the diet, but the correct prediction of milk from stabled cows fed fresh grass indoors proved difficult. The FA profile of organic/biodynamic milk was different compared to conventional milk but an unequivocal discrimination was not possible either in summer or in winter.