Effects of Extended Water Restriction on Performance, Behavior, Health, and Welfare of Feedlot Steers

Climate change and a growing human population are expected to impact water availability globally, which could limit water resources for animal agriculture. As water resources become scarcer, methods to efficiently utilize water will be necessary for livestock production. The following experiments aimed to evaluate methods to identify animals that are more water efficient. These experiments restricted water intake to 50% of ad libitum water intake for 42 d using an Insentec Roughage Intake Control system. In the first experiment, cattle were assigned to a chute score (CS) and exit velocity (EV) rank, and performance was assessed during baseline intake and water restriction. During restriction, DMI, ADG, WI, and G:F were all decreased compared to baseline (P ≤ 0.05). Low CS steers had greater ADG during baseline, but intermediate CS steers had greater ADG during restriction (P ≤ 0.05). There were no EV by period interactions (P ≥ 0.13). The next 2 experiments examined effects of water restriction between steers with different water efficiency utilization. Water efficiency (WE) was calculated as ADG (kg)/water intake as a percent of BW. High WE steers had greater DMI, ADG, and G:F during baseline, but measures were not different during restriction (P ≥ 0.22). Red blood cell counts, hemoglobin, and hematocrit were lower in Medium WE steers, compared to Low and High (P ≤ 0.05). There was no difference in morbidity between WE groups (P ≥ 0.14). Low WE steers had higher rectal temperatures than Medium and High (P ≤ 0.01). There was not a difference in agonistic behavior between WE groups (P ≥ 0.93). During baseline, feeding behavior following a biphasic pattern, where feeding occurred during morning and evening hours, but during water restriction feeding and drinking behavior shifted to early morning hours. These experiments provide information about how beef cattle respond to water restriction, both behaviorally and physiologically. Results of these experiments indicate that there are differences in adaptability between cattle with differing CS and WE