Total tract digestibility of alfalfa hay minerals evaluated by nylon capsule method

The aim was to evaluate the total tract digestibility of alfalfa hay minera ls by nylon capsule method. The trial was performed on two dairy cows in th e second lactation period. The trial took 42 days and was divided into two 21-day periods. The ration consisted of alfalfa hay (4 kg), maize silage 28 .1% DM (30 kg) and mixture (6 kg). The capsules were made of nylon cloth wi th 42 mu m apertures. The capsule shape was lenticular, with 10mm external diameter and 8 mm internal diameter. The capsules were applied orally in th e form of paper bolus. For one application into one cow 1 260 capsules were needed. The results showed that 33.2% of dry matter was lost from the nylo n capsules when they were only washed, with the ash it was 66.2% and with m inerals the values were as follows: Ca 31.3%. P 71.7%, K 98.4%, Mg 80.8%, C u 66.0%, Zn 7.9% and Mn 46.2%. Total average values of total tract digestib ility of the minerals exceeded 90% with P (94.6%), K (99.4%) and Mg (95.8%) . Ca (78.0%), Cu (88.0%) and Zn (77.8%) represented medium values, the lowe st value was measured for Mn (66.5%).