. eight holstein cows in early lactating stage were used in a 4×4 change-over design within 4 periods of 21-d to determine the effects of alfalfa hay particle size and soybean oil supplementation on intake, digestibility, ruminal and blood metabolites, chewing activity, milk yield and compositions. four total mixed rations containing 20, 20 and 60% corn silage, alfalfa hay and concentrate respe...