148 The effect of bunk preference on performance, intake, and efficiency of feedlot steers using an automated individual feeding system.

Automatic feeding systems are being used more frequently to understand individual cattle behavior and intake variation when cattle are group housed. The objective of this experiment was to evaluate if bunk preference exists, and if so, how bunk preference affects performance, intake, or efficiency of feedlot steers. Angus steers (n = 123; initial BW = 293 ± 33.8 kg) were blocked by BW and sire and assigned to 1 of 4 pens, each containing 6 automated feed bunks (Insentec RIC; Hokofarm Group, Marknesse, Netherlands), in a randomized complete block design. Steers were fed a common diet and free to consume feed from any bunk within the pen without restriction. A steer's preferred bunk was defined as the bunk from which the most feed was consumed. In any week, 80% of steers consumed less than 29% of that week's total feed intake from the preferred bunk, indicating no strong preference for a specific bunk. The maximum weekly feed intake consumed from a preferred bunk was 57%. Further, the percentage of intake from the preferred bunk did not affect overall ADG, feed intake, or G:F (P > 0.64). These results suggest that a few steers may have a relatively strong preference for a specific feed bunk; however, this preference was not associated with performance, intake, or efficiency. Researchers can design experiments (at a stocking density of 5 steers per bunk) that restrict or alter an individual animal's access to any specific bunk, because such access, or lack of access, does not alter the animal's performance or feed intake. [ABSTRACT FROM AUTHOR]