Increasing frequency and spatial extent of cattle heat stress conditions in the Southern plains of the USA

Authors: LEE, SANGHYUN - Oak Ridge Institute For Science And Education (ORISE); Moriasi, Daniel; Cibils, Andres; BARKER, PHILIP - Redlands Community College

Submitted to: Livestock Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2025
Publication Date: 4/30/2025
Citation: Lee, S., Moriasi, D.N., Cibils, A.F., Barker, P. 2025. Increasing frequency and spatial extent of cattle heat stress conditions in the Southern plains of the USA. Livestock Science. https://doi.org/10.1038/s41598-025-99621-5.
DOI: https://doi.org/10.1038/s41598-025-99621-5

Interpretive Summary: Oklahoma is one of the major cattle production states in the U.S., but the changing climate poses a threat to this vital industry. We used climate data measured in Oklahoma between 1998 and 2022 to assess how heat stress has changed over time across the state. The impact of heat stress on cattle was determined using thresholds of heat indices such as cattle comfort index. Based on analysis using weather data from 121 state-wide weather stations, we found that more than 60% of the stations showed significant increasing trends in the frequency of heat stress for cattle. This increasing heat stress trend, driven largely by decreasing wind speeds, coincided with notable drops in the number of cattle, particularly in areas where heat stress is most severe. As the number of extremely hot days is expected to increase each year based on this analysis, it's crucial to develop strategies, such as increasing heat-resistant structures and watering locations, to protect cattle health and ensure the continued success of Oklahoma's cattle industry. This information will help cattle producers know trends in heat stress to better prepare to identify and implement appropriate adaptive strategies. Also, this information can guide future research on mitigation techniques and inform state and federal climate adaptation policies aimed at supporting cattle production in Oklahoma and other regions facing similar challenges.

Technical Abstract: Oklahoma, as part of the Southern Plains region, significantly contributes to cattle production in the United States. However, the impacts of climate change can lead to more frequent heat spells, which could exceed critical thresholds and thus adversely affect animal production. We examined the spatio-temporal patterns and trends in temperatures known to cause heat stress which impacts cattle production across the state. Datasets from 121 Oklahoma Mesonet stations between 1998 and 2022 were analyzed to identify the number of days exceeding specific thresholds for cattle production. To do this, the temperature humidity index (THI) and the comprehensive climate index (CCI) were used. While only 12% of stations showed significant increasing trends in heat stress conditions based on THI, over 60% of stations showed significant increasing trends based on CCI. The main driver of the increasing trends identified by CCI was associated with significant decreasing trends in wind speed during the summer. Statewide inventory data showed a significant decrease in cattle numbers, with significant declines following years of high frequency of heat stress conditions detected by CCI. At the county level, decreasing inventory trends often coincided with rising heat stress condition levels, highlighting the potential link between heat stress and cattle health. Given that the number of days experiencing heat stress increased by up to 4 days per year, it is imperative to implement adaptive strategies to mitigate the negative impacts associated with heat stress on cattle health and productivity in this region.