Effects of feed fat on the composition and technological properties of milk and milk fat

The aim of the study was to establish how the addition of rapeseed oil to a processed feed mixture affects the milk produced on commercial dairy farms as well as the composition and quality of the products made from that milk. In this study, replacing grain with processed feed mixture to which 2 or 4 % rapeseed oil had been added was not found to affect milk yield or composition to any considerable extent. As a result of the test feedings, the amounts of myristic and palmitic acid in the milk fat decreased and those of stearic and unsaturated fatty acids increased. This change in fatty acid composition can be viewed as nutritionally desirable, and it also had a good effect on the consistency of butter. During the second test period (4 % rapeseed oil) the cutting firmness figures of the butter were lowest, and in sensory evaluations the butter was also found to have the best consistency. The test feeding had a slight beneficial effect on the composition of milk protein. The amount of casein nitrogen grew and that of NPN fell. However, the test feeding was not found to affect the quality of the market milk, cream, cheese or milk powder