Rumen bacterial diversity associated to Nitrogen retention efficiency in Feedlot steers

This study aimed at characterizing the rumen bacterial diversity of feedlot steers differing in efficiency of N utilization. We hypothesized that the rumen microbial diversity could be associated to the efficiency of N utilization of the host. This study was carried out in accordance with the recommendations of the Brazilian College of Animal Experimentation (COBEA – Colégio Brasileiro de Experimentação Animal) guidelines. The protocol was approved by the Ethics, Bioethics, and Animal Welfare Committee (CEBEA – Comissão de Ética e Bem Estar Animal) of the School of Agricultural and Veterinary Studies (FCAV) of the Universidade Estadual Paulista (UNESP), Jaboticabal campus, Brazil (Protocol number 16688/16). Ruminal cannulation was conducted 3 months prior to the experiment under xylazine sedation and local anaesthesia with lidocaine hydrochloride, and all efforts were made to minimize suffering.