Effects of farming systems on fatty acid composition of cow, goat and ewe milk evaluated with mid-infrared spectroscopy

Factors affecting milk fatty acid (FA) composition were evaluated in 2010 in 1157 Holstein, Montbeliarde and Normandy cattle farms, 209 Alpine and Saanen goat farms and 162 Lacaune and Manech Red Head sheep farms. The lactation stage strongly increased saturated FA (SFA) in bovine milk until the fourth month. This impact was lower in goat and ewe milk. Monounsaturated FA (MUFA) content varied in the opposite direction, and polyunsaturated FA (PUFA) content was relatively stable over lactation. Saturated FA content increased in ewe milk with age at first lambing. This effect was lower in goats. Seasonal calving period did not influence bovine milk FA profile but production season did: the minimum level of SFA content was reached in long-day periods. This seasonal effect was lower in goats and was confounded by the effect of grazing period in ewes. The feeding system influence was higher in cattle than in sheep and goats. Grazing and green forage feeding systems had the same influence on FA profile in cow, goat and ewe milk: SFA content decreased especially in cattle, whereas MUFA and PUFA contents increased. The effect of feeding systems that contain preserved fodders on milk FA composition was low.