Effects of extruded linseed dietary supplementation on milk yield, milk quality and lipid metabolism of dairy cows

Twenty Italian Friesian dairy cows were used in an experimental trial to study the effects ofextruded linseed dietary supplementation on milk production, milk quality and fatty acid (FA) percentages of milkfat and total plasma lipids and plasma phospholipids. Control cows were fed a corn silage based total mixed ration(TMR) while treated animals also received 700g/head/d of extruded linseed supplementation. Feed intake was similarbetween groups. Milk yields was tendentially greater for cows fed extruded linseed. Milk urea content (P<0.05)were reduced by treatment. Results showed a significant increase n-3 FA concentration (particularly alpha linolenicacid) and a significant reduction of n-6/n-3 FA ratio in milk fat, total plasma lipids and plasma phospholipids(P<0.001); moreover a reduction trend (P<0.1) of arachidonic acid concentrations was observed in milk fat, totalplasma lipids and plasma phospholipids. At last, treatment enhanced milk fat conjugated linoleic acid (CLA) percentage(P<0.05).[...