Growth, slaughter performance and feeding behaviour of young bulls belonging to three native cattle breeds raised in the Alps

摘要

The study aimed at assessing growth and slaughter performance, feeding and social behaviour of young male stocks belonging to three native cattle breeds raised in the Central-Eastern Italian Alps: Alpine Grey (AG), Burlina (BU), and Rendena (RE) comparing them to the ones of Italian Simmental (IS), a cosmopolite dual purpose breed. Twelve male calves/breed were selected by experts of their breeders association and transferred to the experimental fattening unit at an average age of 113.9 +/- 12.4 days. After a 70-day adaptation period, calves of each breed were assigned to 3 multiple pens of 4 animals each balanced according to their body weight. The experimental fattening period started when the animals had an average live weight of 204 +/- 6 kg and it lasted when all young bulls reached the optimal finishing. The animals were fed ad libitum the same fattening diet distributed as total mixed ration once a day in the morning. The average daily gain of IS was 1.40 kg/day and it resulted significantly higher than AG and BU (1.16 and 1.20 kg/day respectively), while RE were intermediate (1.24 kg/day). Dry matter intake (DMI) of AG (6.34 kg/day) was lower than IS (7.45 kg/day), while the other two native alpine breeds showed intermediate values (BU=7.12; RE=6.99 kg/day). However no breed effect was observed for feed conversion ratio as well as for the number of medical treatment days. On average, the young bulls spent 215 min/day eating and 405 min/day ruminating and there was no breed effect on these activities neither when they were expressed per hour nor per unit of DMI. Regardless of the breed, more than 70% of DMI was ingested during the first 8 h after diet delivery. Rumination was instead prolonged during the evening hours and overnight. Feed selection indexes did not show any significant difference among breeds. Bulls of AG and RE reached the optimal finishing status at a younger age than BU and IS. Carcass weight of IS was the highest (336.2 kg) while the three native alpine dual purpose breeds had similar values (AG=284.3; BU=290.9 and RE=300.9 kg). No breed effect was recorded for carcass dressing percentage, SEUROP and fatness scores, Based on these findings, the use of these native cattle breeds in the Alpine area should be encouraged not only for cattle biodiversity issue but also for the interesting opportunity given by their dairy and beef production.