Effects of Different Levels of Fish Oil and Canola Oil on Productive Performance of Holstein Dairy Cows

To examine the effects of different levels of fish and canola oils on dairy cows performance, eight early lactation cows were fed diets supplemented with either 0% oil (Control), 2% fish oil (FO), 1% canola oil + 1% fish oil (COFO), or 2% canola oil according to a double 4 × 4 Latin square design. Experimental analyses were restricted to the last week of each period. Milk production, concentration and production of milk protein, lactose and SNF were all similar between diets. The percentage and production of milk fat decreased significantly in all oil supplemented diets. DMI and CP intakes significantly decreased in FO diet, but intakes of OM, NDF and ADF did not change between diets. Fat intake and most of fatty acid (FA) intake increased significantly in supplemented diets. The blood metabolites were all similar between diets. Supplementing diets with fish oil and canola oil had no significant effects on rumen PH and N-NH₃.