Sun, P., Wang, J.-Q., Liu, Q.-S., Khas-Erdene and Yang, G. 2012. Short Communication: Effects of duodenal infusion of increasing amounts of αlinolenic acid on composition and susceptibility to peroxidation of blood lipids in lactating dairy cows. Can. J. Anim. Sci. 92: 219-223. Duodenal infusion of increasing amounts of αlinolenic acid (LNA) in dairy cows linearly decreased the percentages of 18:0, 18:2n-6 and saturated fatty acids (P<0.01), linearly and quadratically reduced 23:0 and 18:1 cis-9 (P<0.01), but linearly increased the content of 18:3 n-3 and PUFA (P<0.01) in blood plasma. As amount infused increased, concentrations of high-density lipoprotein cholesterol and total cholesterol increased quadratically and peaked at 139.9 mg dL^-1 and 182.0 mg dL^-1, respectively (P<0.01). No differences were observed in the activity of blood serum total superoxide dismutase and total antioxidant capacity, but the thiobarbituric acid reactive substances tended (P=0.07) to increase linearly. Duodenally infused increasing amounts of LNA altered the composition of fatty acids and distribution of lipids in blood, but did not affect the oxidative stability of the blood in dairy cows.