02015nas a2200157 4500008004100000245004900041210004900090300001500139490000700154520155200161100001701713700001701730700001601747700001701763856007701780 2010 eng d00aClimate change and cattle nutritional stress0 aClimate change and cattle nutritional stress a2901 -29110 v163 a
Owing to the complex interactions among climate, plants, cattle grazing, and land management practices, the impacts of climate change on cattle have been hard to predict. Predicting future grassland ecosystem functioning relies on understanding how changes in climate alter the quantity of forage produced, but also forage quality. Plant protein, which is a function of plant nitrogen concentrations, and digestible energy limit the performance of herbivores when in short supply; moreover, deficiencies can be expensive to mitigate. To better understand how changes in temperature and precipitation would affect forage protein and energy availability, we analyzed over 21 000 measurements of cattle fecal chemistry acquired over 14 years in the continental US. Our analysis of patterns in forage quality among ecologically defined regions revealed that increasing temperature and declining precipitation decreased dietary crude protein and digestible organic matter for regions with continental climates. Within regions, quality also declined with increased temperature; however, the effects of precipitation were mixed. Any future increases in precipitation would be unlikely to compensate for the declines in forage quality that accompany projected temperature increases. As a result, cattle are likely to experience greater nutritional stress in the future. If these geographic patterns hold as a proxy for future climates, agriculture will require increased supplemental feeds or the consequence will be a decrease in livestock growth.
1 aCraine, J.M.1 aElmore, A.J.1 aOlson, K.C.1 aTolleson, D. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2009.02060.x