Effects of different forms of canola oil fatty acids plus canola meal on milk composition and physical properties of butter

Abstract

Twenty multiparous Holstein cows were used in a 16-wk trial. A block of 10 cows received a control diet, based on corn silage, and the other block of 10 cows successively received four diets with 1) an extruded blend of canola meal and canola seeds, 2) canola meal and whole canola seeds, 3) canola meal and ground canola seeds, or 4) canola meal and calcium salts of canola oil fatty acids. Canola fat represented about 2% of dietary dry matter. Compared to control cows, treated cows had similar dry matter intake, milk production, and daily milk output of true protein or fat. Protein contents of milk was decreased by all treatments, with a lower effect of extruded or whole canola seeds. Milk fat contents was lowered by all treatments, extruded seeds and calcium salts resulting in most important effects. All treatments lowered the percentage of fatty acids with 12 to 16 carbons in milk fat, increased C18:0 and cis-C18:1 percentages, and the proportion of liquid fat in butter between 0 and 12°C. Calcium salts and, to a lesser extent extruded seeds, resulted in most important improvements of milk fatty acid profile and butter softness, whereas whole seeds had low effects.