P.PSH.1314 - Assessing practical interventions to reduce calf wastage and herd mortality in northern systems

Summary

Through rising temperatures and increasing frequencies of extreme weather events, climate change poses a significant threat to the north Australian beef industry. The impact of heat stress on cattle is well documented in both the dairy and feedlot industries, with reduced growth rates, reproductive issues, and increased mortality all being impacted. However, there is limited research of the effects heat stress can have on beef cattle within extensive grazing systems. This project was developed to address these gaps, with a focus on using sensors to capture cattle behaviour and physiological responses to heat.

Objectives

The objectives of this project were related to the development and evaluation of sensor technologies to enable the collection of critical data on cows, calves, and environmental factors experienced by animals in extensive landscapes, and to increase understanding of the impact of heat stress on cattle in northern Australia.

Key findings

There are several behavioural and physiological changes in cow and calf behaviour, in response to increased heat load, which could be effectively monitored using sensor systems. 

Changes included reduction in rumination, changes to grazing activity towards coolers periods of the day, increased time spent near water and shade, and elevated rumen temperatures. 

These indicators were evaluated in relation to various weather metrics, revealing consistent trends across multiple parameters. Despite the inclusion of more complex indices, such as BGHI, the findings indicated that in this situation, mean temperature alone was sufficient to gauge the impact of heat stress on cattle. This highlights the pivotal role of temperature in influencing heat stress related behaviours in extensive environments.

Benefits to industry

This project has increased understanding of how tropically adapted cattle in northern Australia respond to heat stress, and has demonstrated how sensors could be used to capture indicators in extensive grazing systems. This could empower producers with real-time data to manage and mitigate heat stress in their livestock.

MLA action

MLA continues to invest in research, development, and adoption projects to increase understanding of environmental stress in extensive systems, and to develop practical mitigation strategies.

Future research

Continued research in this space has potential to develop a more comprehensive understanding of its impacts across other environments, locations, and management systems in north Australia. Further research is required to understand how behavoural and physiological responses to environmental stress are translated through to productivity impacts, and to develop practical mitigation strategies.