Feeding efficiency and behaviour of growing bulls from the main Italian dual-purpose breeds

To characterise the main Italian dual-purpose breeds in terms of feed efficiency and behaviour, the dry matter intakes (DMI) of 890 young bulls were collected using automatic feeding systems in two Italian genetic centres. In Experiment 1, Italian Simmental (IS), Rendena (RE) and Alpine Grey (AG) young bulls were fed total mixed ration for 46 days. In Experiment 2, Valdostana Red Pied (VR) and Black Pied and Chestnut (VB) young bulls were fed hay and concentrate for 60 days. The IS and RE bulls grew faster than AG (1.6 vs. 1.3 kg/d, p < .01). The DMI was highest for IS and lowest for AG while all breeds had similar values for DMI expressed as relative to body weight. Overall, RE and AG bulls were more efficient than IS. Regarding feeding behaviour, the number of feeding events for IS and AG was higher than for RE, while the feeding time was not different between breeds. The IS bulls showed a higher value of feeding rate (FR) than RE and AG (98.2 vs. 83.1–86.5 g DM/min, p < .01). Overall AG breed, despite its high feeding activity, was particularly efficient. In addition, efficient animals showed a low FR compared to inefficient ones. In Experiment 2, VR and VB strains were quite similar in terms of growth capacity but VR was more efficient despite its higher daily activity. In conclusion, dual-purpose breeds can reach notable growths and feed efficiencies and FR is well related to feed efficiency.