Alternative for modifying the fatty acid composition and decreasing the cholesterol level in the milk of cows

The goal of the experiment that was carried out on Friesian cows was to study an opportunity of decreasing the cholesterol and increasing the level of polyunsaturated fatty acids in the milk fat leaving the milk yield unchanged. The investigations were conducted in year 1999 and repeated again in 2000. Cows were randomly assigned into two groups: control (16 cows) and experimental (19 cows), and fed a total mixed ration (TMR) ad libitum. During the 7 weeks of the investigations the ration of the experimental animals was. supplemented with 21 g linseed and 21 g/day trace element-mineral mixture containing Mg, Fe, Cu, Co, Mn, Zn, Se, Cr and CaCO3. The cholesterol level in the milk of the experimental cows appeared to be 32% lower than in controls. The additives applied affected favourably also the fatty acids' composition. The proportion of unsaturated fatty acids in the milk of the experimental cows was found to be 15% higher and that of saturated fatty acids 8% lower in comparison with the control animals. The most pronounced changes occurred in the CLA and linolenic acid content of the milk fat. The supplement had a small if any effect on the milk production and on the milk fat, protein and lactose content of the milk. The repeated experiment confirmed results of the first trial. (C) 2002 Elsevier Science B.V. All rights reserved.