Future Projections from the Effects of Heat Stress on Livestock: for the US and New England Region

Abstract:

Future climate change will result in variations in heat stress experienced by livestock, which will consequently impact health, well-being, and yield. In this study, we estimate future yield changes for livestock due to heat stress in New England. We use the Community Land Model version 4.5 (CLM4.5), a component of the Community Earth System Model (CESM) that is developed by the National Center for Atmospheric Research (NCAR). The simulation uses RCP8.5 boundary conditions, and is driven by CCSM4 atmospheric forcing from the CMIP5 archive, that conducts simulations of the past and next century. Heat stress metrics are calculated using the HumanIndexMod in CLM4.5 for the early and late 21st century. For example, the humidity index for comfort and physiology, wet bulb temperature and swamp cooler efficiency. Results indicate that in the New England Region, temperatures will increase by 4 °C and in New Hampshire specifically by 3 °C. Temperature humidity index for comfort and physiology, swamp cooler efficiency and wet bulb are all projected to rise by the end of the century. While it is obvious that these elevations in temperature will have a negative effect on animals inhibiting their performance and output, our analysis also emphasizes the role of changes in humidity in heat stress. We show that heat stress caused by temperature and humidity increases, will decrease overall production yield for dairy and beef cattle, sows, finishing hogs and poultry, as a result of heat stress and other major climatic factors. We estimate and discuss resulting economic losses for the livestock industries and the impact in the United States and New England Region.