The influence of the botanical composition of pastures on milk fat composition was studied in the lowlands (alt. 600-650 m), in the mountains (900-1, 200 m) and in two regions of the lower Alps (1,400-1,920 m, 1,275-2,120 m). Generally, besides graminae present at all altitudes, the highland pastures are richer in non-leguminous herbaceous dicotyledons whereas the lowlands produces more leguminous plants. The fatty acid and glyceride composition of 49 cream samples from these four regions was determined by gas chromatography. Pasture botanical composition had a marked influence on milk fat composition. The levels of saturated short chain (C4-C16) fatty acids were lower, and those of unsaturated long chain (especially C18:1, C18:2 and C18.3) fatty acids higher in the three highland zones. The levels of linoleic acid were significantly different in the four zones considered, increasing with the altitude. The levels of short (C28-C36) and medium chain glycerides (C42-C46) were also lower, and those of long chain glycerides (C50-C54) higher in the three highland zones than in the lowland zones. These significant differences in milk fat composition are probably due to the intake of higher quantities of non-leguminous herbaceous dicotyledons. Patty acids and glycerides might therefore be valuable components for identifying Protected Designated Origin (PDO) ``highland`` cream and cheese
