Cattle Heat Stress Measurements

March 20, 2017 Monica Devlin Comments

When it comes to heat stress in cattle, Dr. Dan Thompson, KSUCVM Professor of Production Medicine, says, "It’s not a matter of if, it’s a matter of when."

With warmer temperatures on the way, producers should be prepared to take action to protect their herd and profits from the effects of heat stress. Check out this clip of DocTalk to hear about the combination of factors that contribute to dangerous levels of heat stress.

How do you know when it’s time to take action? Use the following cattle-specific heat stress measurements as guidance to know when it’s time to implement your heat stress management plan.

Cattle Specific Heat Stress Measurements and Models

Once cattle display clear signs of heat stress, losses in productivity and health have already occurred. Left unaddressed, heat stress can progress to the death of the animal, sometimes with little warning. Three measurement schemes have been developed and implemented within the industry to provide cattle-specific guidance for when heat stress management plans need to be implemented: Temperature-Humidity Index ("THI"), Heat Load Index ("HLI") and Accumulated Heat Load Units ("AHLU"). AHLU is the most complete guidance system because it tracks cattle body heat accumulation over multi-day/night heat events. Cattle begin to accumulate heat over various HLI thresholds depending upon both animal and pen conditions. Spot measurements alone cannot tell you the built-up stress caused when hot days are followed by warm, humid nights.

A convenient way to monitor and log these critical measurements is by using a portable, handheld Kestrel 5400AG Cattle Heat Stress Tracker. The Kestrel 5400AG Cattle Heat Stress Tracker can be easily set up for a particular group of cattle with simple menu picks for animal and environment variables. It can then be mounted at the pen where it will automatically track day and night conditions and calculate the current AHLU. You can even receive alerts on your mobile phone signaling the right time to implement heat stress management plans for maximum effect with minimum cost.

Click here to download your complimentary Excessive Heat Stress Action Plan chart.

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Monica Devlin