Impact of increased climate variability on Australian feedlots

Summary

This project was undertaken to investigate the effects of possible future climate scenarios for each of the five major feedlot regions in Australia with a particular focus on management of effluent and water reticulation and on excessive heat load events (EHL). The project involved generation of predicted climate data for five locations across Australia representing the geographic distribution of feedlots within the country, and comparing patterns of change to historic climate data for the same locations.
All climate models showed a gradual and progressive rise in temperature over time (2010-2099) at all locations with the increase generally being higher as the severity of climate change was increased from mild to severe at each location. Rainfall changes were less consistent and some locations showed a reduction in average annual rainfall over time while others showed some increase and generally more variability. There was little evidence of any increase in risk of pond overtopping under any predicted climate scenario with the exception of one location (northern NSW) and under the most severe climate change scenario when pond overtopping rates increased.
There was a progressive rise in the risk of excessive heat load events and associated heat stress in feedlot animals over time, at all locations. When current risk mitigation strategies were applied these effects were all reduced to the levels similar to historic patterns. Drinking water requirements rose at all locations over time and under all climate change scenarios while water runoff volumes tended to decline and become more variable. These findings indicate that heat load management and prevention and water security will become more important in the future.