Estimated requirements of net energy, digestible protein and NDF intake of Chianina young bulls from 400 kg liveweight to slaugter

Three equations have been elaborated and proposed to predict the requirements of net energy and protein digestible in the intestine and NDF voluntary intake of growing young Chianina bulls, starting from 400 kg live weight. The animals examined in the present study were 100 young Chianina bulls starting from about 400 kg live weight, at 10 months of age, up to the average slaughter weight of 800 kg at 20 months average age. The diet was based on hay and concentrates. The equation for the prediction of net energy fits quite perfectly to another experimental equation formerly proposed by Giorgetti and is characterised by a very high value of the correlation coefficient for the regression comparison between observed and predicted figures (R-2=0.90). The statistical reliance degree of the PDIN prediction equation is lower, but still very good (R-2=0.75 between observed and predicted values), but that of the estimate of NDF daily intake resulted very poor (R-2=0.26 between observed and predicted values), probably due to the non homogeneity of the intake capacity of the 100 examined animals. The correlation between daily gains and the concentration of NDF in the diet DM results good (R-2=0.87), showing that young Chianina bulls take advantage of the diet fibre.