Mapping Potential Risk of Exposure to Heat Stress for Dairy Cattle Under Current and Future Projected Climatic Conditions in Uganda

Abstract

Heat stress is a major stressor of dairy livestock production nearly everywhere in the globe, and it is only going to get worse as the world gets warmer. The aim of the study was to map areas where dairy cattle are susceptible to experiencing heat stress under current and future projected climatic conditions in Uganda. The specific objectives included (i) Investigate the trend of heat stress for dairy cattle during the current and future periods, (ii) Map areas and dairy cattle are at risk of exposure to heat stress under current and future climate conditions, and (iii) Determine adaptation strategies and options for the impact of heat stress across the dairy value chain. The study follows a transdisciplinary approach by leveraging geoinformation techniques. Using ERA-Interim reanalysis dataset for the historical period (1981-2010) and for two periods in the future (2021-2050 and 2071-2100) climate predictions of ten global circulation models (GCMs) under Representative Concentration Pathways (RCPs) 4.5 and 8.5 emission scenarios. This study demonstrates a significant rise in the historical prevalence of severe heat stress in dairy cattle (p<0.05) over time in 38 percent of the country. Much of the significant rise is concentrated in the country's northern and central regions. Under future climate conditions, simulations under both RCP scenarios predicted that the country would gradually deteriorate to increasingly severe conditions. On average, milk decline due to heat stress is anticipated to be 2.3 and 15.6 kg milk/year/dairy cow for 2021-2050 and 2071-2100 respectively based on RCP 8.5. Even though dairy farmers are already adapting to heat stress, future heat stress management techniques will necessitate informed climate smart technologies aiming at embedding resilience in current dairy production systems. The findings of this study are concerning, mainly because they show that the effects of heat stress have a substantial effect on Uganda's dairy production systems. The results can be utilized to assist stakeholders in the livestock industry in creating policies that are supported by data and planning, as well as to direct resource allocation in the industry toward the development of adaptable and flexible production systems that can survive future heat stress.