nutrient balance condition in dairy farms of south west of tehran province

this research was conducted to study the nutrient balance condition of dairy cattle in semi industrial dairy farms of sought west of tehran province (eslamshahr) by the questionnaire techniques. the farms based on the herd were categorized in 6 group as follows: 1(1-30), 2(31-60).3(61-100), 4(100-130), 5(130-200) and 200 heads upward. the 30 farms have been selected randomly based on the randomized category sampling methods. in this survey more than 130 dairy farms (at least) including 1500 dairy cows' were investigated. the given ration has been compared with nrc tables and the differences were reported.the results showed that differences on dry matter intake, crude protein and net energy lactation per cow per day in 6 groups were 42.5, 18.1, 6.6, 21.8, 10.4, 17.4 and 36.5,-4.8,-23.5,-4.9,-16.4, 3.8 and 8.4,-0.7,-7.1, 3.02,-3.02 and 1.5% consequently. the differences for minerals of ca and p were42.4,19.8,22.5,8.4,29.9,13.4 and 53.1, 39.1, 38.7, 43.6, 37.4 and 39.2 respectively. the amounts of ndf and adf in all categories were higher than recommended levels. the daily received amounts of k, mn , cu, zn .fe, mg, adf and ndf were higher than recommended levels too. mineral imbalance in ration have very important role in farm income and dairy cattle health. for this reason education and increasing information of farmer about this matter, are very important.