four-handed fifty lactating holstein cows with mean body weight of, 597± 40 and 50±20 and days in milk body condi from sure of 3.1±0.4 were blocked by parity and randomly assigned to 3 treatments. each treatment had 3 pens and each pen had 50 cows. the experiment lasted for 60 days (10 days adaptation and 50 days collection period). concentrate to forage ratio was 60 to 40 and alfalfa hay repla...