نادر سلمان موحدی

Effect of zeolite in preparturient diet on production, and reproduction traits in a completely randomized design with repeated measurements in time was studied. Diets included: 1) Control group (without zeolite), 2) Control+0.75% Zeolite, and 3) Control+1.5% zeolite. Dietary Ca was based of NRC recommended. The diets were fed to the animals during the last 15 days of gestation. After calving, all animals were fed with the same diet and their performance was evaluated. The control group had better raw milk production, and dry matter and energy intakes, but feed efficiency was higher in zeolite-consuming cows (P≤0.01). Protein, NDF and ADF intakes and corrected milk production (4%) were not significantly different among the groups. The milk fat percentage of zeolite-consuming cows were higher than the control (P≤0.01), but the percentages of protein, lactose and SNF were not significantly different. Plasma concentrations of total Ca, Ca++ and their ratio were similar during calving, but higher in zeolite-consuming cows at 6, 12 and 24 h postpartum (P≤0.01). The frequency of hypocalcaemia and postpartum disorders were higher in the control group than the other two groups (P≤0.01). Body condition score and colostrum quality of zeolite-consuming cows were higher than the control (P≤0.01). According to the results of this research, the use of zeolite at the level of 1.5% DM of preparturient diet is recommended and compared to the level of 0.75% DM and control group, it has a better effect on controlling blood Ca concentration and improving the production and reproductive traits of cows.