The Great Plains provide amajor portion of US beef cattle production, and beef cattle represent the largest sector of the regional agricultural economy. Cattle producers regularly contend with climate variability, but the consequences of this variability are less well understood than for cropping systems. A retrospective analysis of US Department of Agriculture AgCensus data was conducted to assess the extent to which climate variability (1978-2017) has affected the spatial and temporal distribution of beef cow numbers throughout the Great Plains. Cow numbers were remarkably stable, declining only 3.1% between 1978 and 2017. However, beef production increased 30% during this period, in response to a steady increase in live animal slaughter weight. Cownumbers decreased during droughts in the late 1980s and the early 2010s but recovered before the subsequent 5-yr census. Cow numbers decreased 5.1%, 8.8%, and 4.0% in the Northern, Central, and Southern Plains, respectively, between the 1982 and 1987 censuses, even though annual precipitation only decreased in the Northern Plains. The reduction in cow numbers during the 2010s drought, which is assumed to portend future extreme droughts, was greatest in the Southern Plains (- 17.6%) followed by the Central (- 11%) and Northern Plains (- 4.9%), compared with the 2007 census. The relative increase in beef cow numbers in the Northern Plains may represent an emerging signal of climate variability on rangeland beef production. This may be a consequence of weaker correlations between cow numbers and mean annual precipitation and temperature established by lower mean annual temperatures in the Northern Plains. This retrospective analysis indicates that continued climatewarming and drying will adversely affect rangeland beef production, it identifies a large knowledge gap between climate variability and sustainable rangeland beef production, and it provides a reference to begin assessing the vulnerability of rangeland beef cattle production in future climates. (C) 2019 The Society for Range Management. Published by Elsevier Inc. All rights reserved.
Klemm, T; Briske, DD
Retrospective Assessment of Beef Cow Numbers to Climate Variability Throughout the US Great Plains
Rangeland Ecology & Management