Transfer of alpha-linolenic acid from forage diets to milk in lactating Holsteins

Whiting, Cory Margaret
Journal Title
Journal ISSN
Volume Title
University of Guelph

This experiment was designed to estimate the apparent transfer of linolenic acid (18:3) from the diet to milk in cows fed fresh and conserved alfalfa forage. Sixteen multiparous Holsteins were involved in a cross over design with three five week periods. Results from the fifth week of each period indicated that cows fed fresh forage had significantly (P < 0.0001) higher levels of 18:3 (1.05 vs. 0.79g/100g fat) and conjugated linoleic acid (CLA)(0.17 vs. 0.07g/100g fat) in their milk compared to cows fed silage. The enrichment of 18:3 in milk from fresh forage fed cows was represented in the lipid concentration of rumen bacteria (6.52% of fatty acids vs. 3.02%). The apparent transfer of 18:3 from diet to milk was 4.36% and 3.81 % for the fresh and silage groups respectively. Fresh forage feeding resulted in milk with lower saturated, and higher polyunsaturated fatty acids, particularly CLA and 18:3, compared to similar forage that had been ensiled.

transfer, linolenic acid, diet, milk, cow, fresh, conserved, alfalfa, forage