Effects of Processing Methods on Sainfoin Digestibility, Degradability and Rumen and Blood Parameters of Holstein Dairy Cows

This experiment was carried out to study the effect of deactivation of sainfoin phenolic compounds using PEG (6000) and water on sainfoin digestibility، rumen and blood parameters of Holstein cows fed with sainfoin. This trial designed using 3 nonlactating ruminally cannulated multiparous Holstein cows، in balanced changeover design consisted of 3 diet and 3 periods of 17 days (10 days for adaptation and 7 days for sample collection). Extractable tannin content of control forage was 21. 3 (g/kg DM). Both of treatments were able to decrease it more than 90 percent. Treatments resulted in increased digestibility of organic matter، crude protein، forage cell wall and metabolisable energy of sainfoin (P<0. 05)، but no effects have been found on total concentrations and molar proportions of rumen volatile fatty acids. Tannin deactivation can cause elevation of ruminal ammonia nitrogen concentration (P<0. 05)، but blood urea، glucose and creatinine concentrations were not affected. Tannin deactivation increased DM degradability of sainfoin in PEG treated group (P<0. 05). We concluded that PEG and water treatments diminished phenolic compound in sainfoin and could elevation of nutrient availability، especially in the case of nitrogen. Water treatment was practical method for processing of sainfoin in Iran and can be used on the farm.