293 Evaluation of the Water Footprint of Beef Cattle Production in Nebraska

Abstract Data were compiled from an experiment evaluating the effects of month of calving, wintering system, and calf management on cow and calf performance to model the amount of water (green and blue) required to produce beef in Nebraska production systems. The referenced study was conducted over four years utilizing 217 cow/calf pairs per year. Cows were wintered on either native range or corn residue and month of calving was March, June, or August. Calves were managed as calf-feds or yearlings and only steer calves were included in the model. A 365-d period was utilized to estimate the cow’s contribution of water inputs based on dry matter intake throughout the year varying by production system. Diet characteristics, dry-matter intake, days on feed, average daily gain, and hot carcass weight were measurements used to estimate water utilization by the calves. The total water footprint was calculated by dividing the total amount of water used for each system (L) by the amount of boneless beef produced (kg). Production systems where cows were wintered on corn residue utilized 18% less water than systems utilizing native range as a wintering source, because of water allocations using the value fraction method. Increasing the dietary inclusion of distillers grains from 0% to 40% decreased the water footprint in the finishing phase by 29%. Utilizing by-products in replacement of primary crops decreases the overall water footprint of production. Across all scenarios modeled, more than 50% of the water footprint was allocated to the cow grazing rainfed pasture (green water) and over 98% of the water footprint was allocated to growing feed. Improvements in crop water use efficiency will benefit livestock production. The water footprint of the beef systems analyzed was 80% green water as rain, minimizing the environmental impact of beef production on freshwater use and ecological water balance.