A comparison of milk fat composition between pasture based cows supplemented with either canola meal or wheat

Abstract

Increasing the polyunsaturated fatty acid (PUFA) content of milk has been the focus of much recent research. Milk from pasture based cows has been reported to have a high content of PUFA, which can be further manipulated with the addition of supplements differing in fatty acid composition. This experiment used 980 Holstein-Friesian and Jersey crossbred cows in a split treatment design to determine the effect of canola pulp or wheat supplementation on milk fatty acid composition and milk solid production in a typical large pasture based herd. Principle component analysis was used to determine the most influential factors of change in milk composition. Milk solid production did not differ significantly between treatments (P > 0.05), C10:0, C12:0, C14:0, and C16:0 were very significantly (P < 0.001) decreased by the canola pulp treatment. C18:0 anteiso and conjugated linoleic acid were not significantly affected by treatment. C18:1 c9 and C18:1 t9 were very significantly increased (P < 0.001). C18:1 t11 was significantly increased in the canola pulp treatment (P < 0.03). These results show that canola pulp is a potentially valuable supplement for use in grazing based systems. The equivalent response to supplementation compared to wheat would recommend its use if cost on an ME basis was competitive.