EN
Studies have been carried out on 4 fattening steers with permanent rumen fistulas . Corn silage, green alfalfa, pasture lichen and sugar beet top silage were applied. They were supplemented with different forages and concentrates. Samples of rumen content were analysed for pH, N-NH3, total VFA, acetic, propionic and butyric acids, soluble and bacterial N. Using nylon bags in situ, the degradation of nitrogen compounds and dry matter of the feeds examined, was evaluated during 24 hours. High pH values of rumen content / 7 , 5 / was found when green grass and green alfalfa forages were fed. VFA levels for silages and soilages were in the range of 10-11 mmol/and 6,2 - 8,8 mmol/100 ml of rumen content, respectively. The highest concent rations of N-NH3 exceeded 20 - 30 mg/100 mg /urea, green alfalfa, pea/ whereas with green forages they were the lowest /11 mg/100 ml on average/. Bacterial protein synthesis was the most intensive with concentrates in the diets. Degradation of dry matter in bags, after 24 hours varied from 61% /hay/ to 89% /barley meal/ whereas that of crude protein varied from 9% /hay/ to 93% /CJ mixture/.