. 2007. The effects of limit feeding a high-energy barley-based diet to backgrounding cattle in western Canada. Can. J. Anim. Sci. 87: 385-391. A series of three completely randomized design trials were conducted to compare the effects of a limit-fed high-grain diet relative with that of an ad libitum-fed high-forage diet on performance of growing cattle with similar total energy intakes. In trial 1, the ad libitum-fed high-forage diet was formulated to 1.58 and 0.98 Mcal NE m and NE g kg -1 DM. The high-grain diet was formulated to 1.91 Mcal NE m and 1.23 Mcal NE g kg -1 DM. Projected liveweight gains (1.22 kg d -1 ) and the amount of DM provided to the limit-fed high-grain cattle were based on the NE m and NE g equations for liveweight gain of large-frame steers (NRC 1984). A similar feeding regime was employed for trials 2 and 3; however, it was necessary to reduce energy intake equally after 30 d on feed to control weight gains. In trial 1, the limit-fed high-grain cattle had similar (P > 0.05) ADG and lower (P < 0.05) DMI than the ad libitum-fed high-forage cattle, leading to a 15.4% improvement (P < 0.05) in feed efficiency. Feed efficiency was improved (P < 0.05) by 16.9% in trial 2 and by 21.2% in trial 3 for the limit-fed high-grain cattle, primarily as a result of reduced (P < 0.05) DM intake and similar (P > 0.05) daily gains. Back fat accretion rates were greater (P < 0.05) in the limit-fed high-grain cattle, indicating differences in energy partitioning. The incidence of severe liver abscesses was greater (P < 0.05) for the limit-fed high-grain cattle in trial 2. These results indicate that limit feeding a high-grain diet to backgrounding cattle can be employed to target specific rates of gain and improve feed efficiency although managing acidosis to prevent liver abscesses may be an issue. Key words: Cattle, limit feeding, feed efficiency, liver abscesses Klinger, S. A., Campbell, J., Wildeman, B., Block, H. et McKinnon, J. J. 2007. Conséquences d'un régime rationné à base d'orge très énergétique sur l'engraissement des bovins dans l'Ouest canadien. Can. J. Anim. Sci. 87: 385-391. Les auteurs ont procédé à trois expériences entièrement randomisées afin de comparer les effets d'un régime riche en grain mais rationné à ceux d'un régime riche en fourrages mais servi à satiété sur le rendement des bovins en croissance recevant un apport énergétique global similaire. Lors de la première expérience, la ration riche en fourrages servie ad libitum avait été formulée pour fournir 1,58 Mcal de NE m et 0,98 Mcal de NE g par kg de matière sèche. Celle riche en grain avait été confectionnée pour fournir 1,91 Mcal de NE m et 1,23 Mcal de NE g par kg de matière sèche. Le gain de poids vif prévu (1,22 kg par jour) et la quantité de matière sèche fournie aux bovins rationnés reposaient sur les équations de la NE m et de la NE g servant à calculer le gain de poids vif des bovins de grande taille (CNRC 1984). Les auteurs ont recouru à un régime similaire dans la deuxième et la troisième expérience, mais ont dû réduir...