EN
During 90-day period 18 fistulated young bulls, divided into 3 groups were respectively fed: ground pelleted diet "a"; diet "a/b" i. e. pellets ("a") until the 62nd day and then hay + bran ("b") and control diet "b" composed of long hay + wheat bran with mineral additives. The animals of both groups receiving pelleted fodder exhibited clinical sings of indigestion characterized by anorexia, parorexia, lack of regurgitation reflex, hypotony and rumen tympany. This was accompanied by biochemical symptoms of partially compensated metabolic acidosis in blood acid-base parameters and by alterations of pH value, consistency, protozoa population and molar ratio composition of volatile fatty acids in the rumen fluid. Post-mortem examinations revealed a generalized hyperkeratosis of forestomach chambers. None of the presented clinical symptoms, biochemical disturbances in the blood and in the rumen fluid and forestomach lesions have been diagnosed in the control animals receiving only hay + bran ("b").