The effects of limit feeding a high-energy barley-based diet to backgrounding cattle in western Canada

Abstract

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 NEm and NEg kg-1 DM. The high-grain diet was formulated to 1.91 Mcal NEm 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 NEm and NEg 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.