303 Accuracy of the Smartscale In-Pen Weighing System

Abstract

Abstract The Beef Improvement Federation recommends repeated body weight (BW) measures in a 70-d test period for accurate assessment of average daily gain (ADG) in growing animals. In-pen automated scale systems enable daily monitoring of BW and ADG without the additional labor, time, and animal stress that is associated with recording static chute BW. The objective of the current study was to determine the utility of partial body weight (pBW) for estimating full BW and average daily gain (ADG) in growing steers. SmartScales (C-Lock Inc.) were positioned in front of water troughs and used to measure front-quarter pBW while animals were drinking. Partial body weight was used to estimate full BW using an internally developed slope-intercept equation. The dataset consisted of pBW, estimated BW, and recorded BW for 300 steers in a 50-d feed performance test. Single-day chute BW were recorded on days 14, 28, 35, and 50. Relationships and errors between estimated BW and recorded BW were evaluated. Individual animal ADG estimates were calculated and compared using estimated and recorded BW measurements. Steers in the study visited the water trough an average of 4.3 ± 2.6 times per day. On average, pBW explained 96.1% variation in recorded BW. Average predicted BW and recorded BW differed by 8.3 ± 6.4 kg, or 0.15 ± 3.0 %-units. Average daily gain calculated from pBW and recorded BW were strongly correlated (r = 0.83). On average, ADG calculated using pBW and recorded BW differed by 0.14 ± 0.12 kg, or 8.8 ± 8.0 %-units. Real-time pBW collected using in-pen weighing systems can be used to accurately estimate full BW and ADG.