435 Water footprint of stocker beef production.

Abstract

Analysis of the water footprint (WF) of beef stocker production in the Southern Great Plains of the U.S. provides information leading to more efficient use of land and water resources where water resources are in decline. For illustration, I present various methods of water footprint calculation to compare grazing systems for beef steers consisting of largely of a grass-only system versus a grass-alfalfa system. Water footprints averaged 32.8 and 21.8 m3 of water kg-1 of liveweight gain (P < 0.01), respectively, when water included rainfall, irrigation, and livestock drinking. Water footprints of groundwater sources were 3.3 and 2.4 m3 of water kg-1 of beef liveweight gain (P < 0.01). When calculations included the conversion of excess grass harvested as hay to theoretical gain, the grass-only system had a lower WF than the grass-alfalfa system. Including a high quality and productive legume such as alfalfa can reduce the WF of steer weight gain thanks to greater rates of gain from the higher quality forages, thus lessening an important source of inefficiency in converting feed to animal growth.