Effects of Abomasal Infusions of Safflower Oil or Elaidic Acid on Blood Lipids and Milk Fat in Dairy Cows

Abstract

In each of three trials with abomasally-fistulated lactating Holstein cows, we compared control rations to the same ration plus abomasal infusion of safflower oil or elaidic acid. In Trial 1, 250ml safflower oil were infused over 4h daily for 3 wk. Trial 2 involved infusing 500ml safflower oil over 4h daily for 1 wk. In Trial 3 elaidic acid was infused daily for 1 wk.Infusion of safflower oil in Trial 1 increased milk fat percentage and proportion of 18-carbon polyunsaturated fatty acids in the milk fat. Proportions of myristic, palmitic, stearic, and oleic fatty acids of milk fat decreased. Blood ketones and free fatty acids and cholesterol of plasma were increased by the oil infusion.In Trial 2 the 1-wk infusion of safflower oil did not affect milk fat yield or percentage. The infusion increased the proportion of polyunsaturated 18-carbon fatty acids in the milk fat and decreased myristate, palmitate, and stearate. An increase in plasma free fatty acid was small but significant. Triglycerides, cholesterol, glucose, ketones, and acetate were not affected by the infusion. Intake of hay was depressed by this infusion rate.In Trial 3, infusion of elaidic acid had no effect on milk fat yield or percentage. Blood or plasma lipids did not change.