Wplyw zywienia na poziom niektorych wskaznikow biochemicznych krwi buhajkow rasy fryzyjskiej

The aim of the studies was to determine how the level and variation of the physiological indicators: thyroxine, triiodothyronine, insulin, alanine aminotransferase, aspartate aminotransferase, alkaline phosfatase, urea, glucose, creatynine and cholesterol depend on different feeding. Four samples of the blood were taken from 174 young bulls (7-9 months old) before morning feeding. The first blood samples were collected under standard feeding conditions while animals were fed a diet of corn silage and hay with supply concentrates. The second sampling was done 36 h after fasting. Next the animals were offered mixed concentrates and hay ad libitum for 42 days and the third sample was taken. The last sample was collected after 36 h of fasting. The variation of all indicators was high (except glucose). No effect of the feeding and fasting period on the activity of alanine aminotransferase was determined. The animals showed a higher level of aspartate aminotransferase and creatynine after silage and hay feeding compared to ad libitum concentrate feeding. The variability of biochemical indicators showed that their level is dependent on many environmental factors and physiological conditions.