Why is heat stress an issue for cattle? Heat stress is a combination of external heat load (the weather) and the internal heat load.
For humans the internal heat load is generated by physical activity but for cattle in a feedlot it is the increased metabolic rate due to a high energy diet they are fed. Feedlots managers can reduce the internal heat generated by changing the feed to a lower energy diet. This requires advanced warnings of potential events to be effective.
Katestone scientists have worked with researchers at the University of Queensland since 2000 to better understand the drivers of heat stress in feedlot cattle. This research, funded by Meat and Livestock Australia (MLA), has assisted the development of tools to help operators manage heat. The outcome is an Australian developed Heat Load Index (HLI) – arguably the world’s best practice for managing heat stress in feedlot cattle.
Understanding the process of heat stored within lot fed cattle requires not only an understanding of current weather conditions but also the history. Unlike humans, cattle can’t cool down overnight in air conditioning, and as such, can sometime carry a heat load into the next day. Given prior warning, feedlot operators can take management actions – such as changing diet – to reduce the likelihood of a heat related event. Therefore it is vital to forecast the accumulated heat load in feedlot cattle and to understand ways to be proactive about managing heat.
The calculation of an accumulated heat load in cattle requires a high resolution data set with all the information needed to estimate the heat load (wind speed, black globe temperature and humidity) on a hourly basis and then integrate this over time.
This is where Katestone’s high resolution weather forecasting system comes into its own. K-NWS (Katestone Numerical Weather System) was developed and is maintained by us to specifically predict heat events for Australian conditions. Each day it calculates the HLI and accumulated heat load at feedlot locations all over Australia and issues site specific forecasts to help protect cattle from heat stress.
Called the Cattle Heat Load Toolbox, this web portal provides advice on how to manage heat in feedlot cattle, and also provides an early warning alert service.
“Feedlot operators can register their location to receive a site specific forecast, set up alerts and undertake a risk assessment for their location and specific conditions. They can also link in their site weather station to use their own data to initialise the forecast. This system is well used and provides warnings for over 300 locations, some of them well away from any major towns,” says Katestone’s Managing Director, Christine Killip.
Since the system was developed the occurrence of heat related deaths in Australian feedlots has significantly reduced.