Effect of intensive fattening of bulls based on a high-grain diet on growth intensity and biochemical and acid-base parameters of blood

The present study deals with the use of high-grain diets with a low proportion of fodder for fattened cattle, and with the evaluation of their effect on the growth intensity and metabolic profile of the animals. Thirty Holstein × Czech Pied bulls were given diets containing from 86.69 to 88.54% concentrates based on crushed cereals in the period from 216th to 327th day of age. The growth intensity of bulls was high, with the average daily weight gain of 1.64 kg in the course of the whole experiment. When the average body weight of animals reached 343.67 kg and 450.93 kg, blood samples were taken from the vena jugularis of 10 randomly selected animals for the assessment of acid-base balance and selected biochemical parameters. Slightly decreased pH values and increased pCO2 were detected by the assessment of acid-base balance. The calculated values of base excess and standard bicarbonate were in the reference range; however in samples of the second collection a highly significant decrease was found (P ≤ 0.01). By a biochemical analysis of blood increased levels of plasma phosphorus were detected in samples of both collections in comparison with the accepted reference range. A statistically highly significant increase (P ≤ 0.01) in plasma urea concentrations was detected in samples of the second collection. Other investigated parameters ranged within the accepted reference values. The results of the experiments show that high-grain diets produced intensive growth with high daily weight gains, without adverse effects on the health status of the investigated bulls. Although some depletion of compensatory mechanisms maintaining the acid-base balance was recorded, no serious disturbance of metabolic profile was registered in the animals.