Effect of Different Levels of Canola Meal on Milk Production Performance and Some Blood Metabolites of Lactation Holstein Cows

In this experiment, effect of Canola meal utilization on milk production performance and some blood metabolites of lactating Holstein cows were studied. Twelve lactating cows in third-parous with average weight of 585±55 kg, milk yield 36±6 kg and days in milk 109±22 were used. A latin square (cross over time) design was conducted in which 4 treatments were tested in 4 period of time and 3 squares. Each period included of 14 days adaptation and 10 days for blood and milk sampling. Milk fat, protein, lactose, total solids, solids non fat and urea and blood 3-Iodothyronine, thyroxin and albumin levels were determined. Results showed by increasing the level of Canola meal in the diets, milk composition such as fat, protein, lactose, total solids and solids non fat were significantly increased but no significantly variation was found for raw milk yield, 4% fat corrected milk and milk urea concentration. In addition, inclusion of Canola meal did not affected the blood 3-Iodothyronine, thyroxin and albumin. It seems that Canola meal can be used as a substitute of diet protein meals up to 75%.