Graphical AbstractSummary:The study evaluated the effect of 2 feeding strategies, fixed grass (GFix) and maximized grass (GMax), on the fatty acid composition of milk obtained from North American (NAHF) and New Zealand (NZHF) Holstein-Friesian cows, determined by gas chromatography of the derivatized milk fat extract. The results showed that there is a significant correlation between grass intake and fatty acid relative concentration, which affects health and technological indices.