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Cattle Heat Loading Forecasting Summer 2007-2008

A weather forecasting system was developed to assist in warning operators of cattle feedlots of impending adverse weather conditions that could lead to excessive heat loads (and potential mortality) for feedlot cattle. This forecasting system covered several locations in the proximity of feedlots where Bureau of Meteorology (BoM) automatic weather stations (AWS) are located.

The forecasts were made over the period 1 December 2007 to 31 March 2008 at 17 sites throughout Queensland, New South Wales, South Australia, Western Australia and Victoria. Forecasts were made of wind speed, temperature and dew point, these being the input parameters necessary to calculate the Heat Load Index (HLI) and ultimately the Accumulated Heat Load Unit (AHLU).

Forecasts for all 17 sites were posted daily onto a website ( for easy access to all feedlot operators.

There was good agreement between the forecast and observed temperature and dew point. The relative humidity was calculated from these parameters. Solar radiation was calculated analytically using the date, time of day and latitude of the site. The wind speed forecasting performance, however, was relatively poor.

Heat stress is divided into four risk categories: low, medium, high and extreme. The risk categories span AHLU values of 0 to greater than 100. The low risk category ranges from 0 to 20 AHLU, the higher risk categories extend over 30 and 50 AHLU. It is more important to predict the risk category well than the actual AHLU. The forecasting system’s performance at predicting the risk category has been found to be good. It is much more difficult to predict individual AHLU values and, consequently, the forecasting system did not perform as well in this regard.

An additional 74 sites were also trialed for the 2007/2008 summer. These forecasts were not made publicly available due to the limited data used to train the models. The forecasting performance at these sites is detailed in Appendix E.


Title Size Date published
575.6KB 16/11/2011


Contract No. Title Start date End date Funding type
Online summer heat load forecast service 2007/2008
01/07/2007 13/06/2008

This page was last updated on 06/07/2018

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