Daily heat load monitoring tool
For cattle in a feedlot their risk of heat stress changes from day to day. The Daily heat load monitoring tool project aimed to:
- develop and test a daily monitoring tool App;
- develop an alternative thermal risk assessment; and
- review alternative forecasts.
Daily monitoring tool
For cattle in a feedlot their risk of heat stress changes from day to day. This is a combination of the physical properties of the animal changing (becoming acclimatised and reducing their risk and then gaining weight to become more at risk), this combined with changing weather conditions and potentially changing pen conditions results in a dynamic system that should be assessed daily to determine the risk of heat stress for a particular cattle population.
The Daily Monitoring Tool (DMT) App was developed by Katestone and available for limited testing in the 2015/16 summer. The App was designed to record the population characteristics, environmental conditions and management practices at participating feedlots. The App trial started in December 2015 with thirteen feedlots verbally agreeing to participate.
Participation by the feedlots in the use of the daily monitoring via the App was unfortunately poor. The limited data collected was analysed but it was difficult to draw any major conclusions regarding the HLI or AHLU concepts without more data. However, it is evident that more work is needed to collect sufficient observations to allow a comprehensive review of the appropriate triggers for a heat event.
Thermal risk assessment
An alternative method for determining the heat stress risk for a site was determined. The method incorporates cattle characteristics, feedlot management practices and the site climatology. The method is illustrated with an example, however, there are insufficient data at this stage to establish the exact form of equations and other parameter values. It is envisaged that these will be forthcoming when the data are recorded in the 2015-2016 summer season and analysed.
Long term climate datasets were also investigated to provide an alternative to sparsely located Bureau of Meteorology automatic weather stations. It was found that the risk characteristics for six representative sites obtained using the MERRA data were in agreement with those obtained using observational data. The frequency of events in the various risk categories is comparable and useable in terms of the original objectives of the RAP – that is, to determine the risk profile of a site.
The performance of K-WRF and the Bureau of Meteorology (BoM) Australian Digital Forecast Database (ADFD) system was evaluated at seventeen BoM automatic weather stations and twenty-eight feedlots that participate in the Heat Load Data Network. The results show that both systems are comparable in their performance in predicting key meteorological variables, the Heat Load Index and the Accumulated Heat Load Unit. The analysis also shows that the accuracy of both systems suffers from the sensitivity and the interpretation of the indices them.selves and to a lesser extent the accuracy of the forecast. Both systems are equally suited to form the basis for a cattle heat load early warning system.
When: 1 Jul 2015 to 31 May 2016
Contact: Andrew Wiebe, Frank Quintarelli and Christine Killip
Collaborator: Katestone Environmental Pty Ltd
For more information, please read the final report summary and download the final report (B.FLT.0392) (PDF, 823.2KB) from the Meat & Livestock Australia website.