PSIX-1 Predicting Beef Cattle dry Matter Intake

Abstract

Abstract As increasing climate variability continues to strain agricultural production, priorities must be aligned with methods to maintain or improve current production processes, including advanced, technology-based methods of measuring individual feed and water intakes and increasing water use efficiency in cattle. A total of 745 animals were evaluated in eight test groups from 11/25/19 to 9/2/21 in a dry lot equipped with In-Pen Weighing Positions and Feed and Water-Intake Nodes. Relationships among average daily gain (ADG), dry matter intake (DMI), residual feed intake (RFI), water intake (WI), residual water intake (RWI), animal performance variables, and environmental variables at the individual animal level were investigated on a first test group of Angus bulls (n = 125) and crossbred steers (n = 53). Root mean square error (RMSE) was used as a measure of error between model-predicted and observed DMI. Random Forest (RF) analysis predicted the daily DMI, with RMSE 0.92 kg for bulls and 0.85 kg for steers. When performance measures were averaged across the entire test period, the RMSE using RF were 0.39 and 0.34 kg DMI for bulls and steers, respectively. Repeated measures Analysis of Variance (RM ANOVA) was used with the same set of predictive variables as in RF. DMI was strongly related to body weight, WI, short wave radiation (MJ), and relative humidity (%; all p< 0.0001). RM ANOVA predicted the daily DMI with (RMSE) 1.5 kg for bulls and 1.41 kg for steers and 0.75 and 0.61 kg DMI for bulls and steers across the entire testing period. Study results identify relationships between DMI, WI and other growth metrics in a dry lot, which must be explored in pasture to identify biomarkers of feed and water efficiency in cattle to improve sustainability of beef production in grazing systems.