PSVII-15 - Evaluation of the Effects of Hormonal Implants on Efficiency, and Water Footprint of Feedlot Steers

Abstract: As freshwater sources continue to deplete, federal policy will likely marginalize water distribution towards agricultural communities more harshly. This ever-limiting resource highlights the significance of proactively improving quantification and water utilization of livestock operations. The goals herein investigated the effects of long-term implants on animal performance and water footprint. Eighteen crossbred F1 Angus x Hereford steers were randomly assigned to implanted (IMP; n = 9) or non-implanted (NIMP; n = 9) groups in two pens equipped with individual feeding gates and four RFID-automated water intake and body weight scales for a period of 135d. Steers were fed the same finishing diet across groups (400 g/kg alfalfa hay, 402 g/kg ground corn, 161 g/kg ground barley, 23.4 g/kg soybean meal, 10.8 g/kg mineral mix, and 2.7 g/kg limestone). Water footprint was classified as green, blue and grey (rainwater, surface/groundwater, and waste/contaminated water, respectively). Statistical analyses were performed on R Statistical Software following a linear mixed model methodology with the implanting treatment as a fixed effect and animal as a random effect to the intercept. Overall, expected increases in feed efficiency and performance were observed on this experiment where implanted animals had greater carcass weights (p < 0.0001), average daily gains (p < 0.0001), and body weights (BW; p = 0.001) all while consuming less feed by unit of BW ( p < 0.0001). With regards to water, the implanted animals consumed less water per kilogram of body weight gain (p < 0.0001). No differences were observed for water footprint evaluations in this experiment (p > 0.5). These results highlight that genetic and metabolic mechanisms regulating feed efficiency on implanted animals may also regulate water efficiency directly or indirectly, and therefore, further warrants the investigation of these pathways in future research.