Impact of a basal diet of hay and fodder beet supplemented with rapeseed, linseed and sunflowerseed on the fatty acid composition of milk fat

The content of fatty acids (FAs) in milk from cows fed a control diet comprised of hay ad libitum and 15 kg fodder beet, supplemented with either 1 kg ground rapeseed (RAP1), 1 or 1.4kg ground linseed (LIN1 or LIN1.4), or 1 or 1.4kg ground sunflowerseed (SUN1 or SUN1.4), was determined using high resolution gas chromatography. The concentration of saturated fatty acids (SFAs) in milk fat from cows fed the control diet was very high and decreased almost linearly as a function of increased daily intake of oleic. linoleic and alpha-linolenic acids of the oilseeds. The highest concentrations of unsaturated fatty acids (UFAs) and conjugated linoleic acids (CLAs) were found in milk from cows fed the SUN1.4 diet. A Supplement of linseed induced the highest content of alpha-linolenic acid in milk fat. Sunflowerseed was the best of the three oilseeds studied for counterbalancing the high content of SFAs and the relatively low content of UFAs in milk fat. (C) 2003 Elsevier Ltd. All rights reserved.