Heat Stress Tracker

Heat Stress Tracker

for Livestock and Agriculture

  • Kestrel - D2AG - 5000AG - 5500AG - 5400AG
  • Heat Load Index, Temperature-Humidity Index, Accumulated Heat Load Units,
  • Wet Bulb Globe Temperature, heat index, Delta T, temperature, humidity...
  • 21 measurements in all!

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The Kestrel 5400 Cattle Heat Stress Tracker offers micro-climate measurement and monitoring at the pen or yard location. Contains a built-in Globe Temperature sensor and complete cattle-specific calculations.

Measure THI and HLI and track AHLU based on easy-to-input herd and pen parameters. Perform spot checks or mount in place with the included vane mount accessory to track AHLU for months.  LiNK capability allows remote access to current and logged data from your iOS or Android mobile device. Mount a mobile data equipped tablet nearby to send mobile alerts even when you’re not on-site. Designed by Kestrel with input from some of the world’s most respected experts in cattle heat stress, the Kestrel 5400 Cattle Heat Stress Tracker is designed to help you MEASURE and MANAGE your herd’s heat stress, ensuring you MAXIMIZE your bottom line.

  • Heat Load Index (HLI),Temperature-Humidity Index (THI),Accumulated Heat Load Units (AHLU),Wet Bulb Globe Temperature (WBGT),heat index, Delta T, temperature, humidity and much more. 21 measurements in all!
  • Complete weather station capabilities with a comprehensive suite of weather measurements including wind speed, direction, pressure trend, temperature and humidity.
  • Durable, portable, and easy to use data logger with customizable category settings, graphing and measurement statistics.
  • Large, hi-res, hi-contrast, graphic display is perfectly readable in the brightest sunlight and is backlit for use in low-light conditions.
  • LiNK connectivity powered by Bluetooth LE® provides wireless communication to mobile devices and computers.
  • Rugged (drop tested to MIL-STD-810G standards),dust and waterproof (sealed to IP67 standards).
  • Included Kestrel Vane Mount easily attaches to fencing.
  • Protective pouch, neck lanyard and Lithium AA battery included.
  • 5-year warranty.



  • Altitude
  • Accumulated Heat Load Units (AHLU)
  • Barometric Pressure
  • Crosswind
  • Delta T
  • Density Altitude
  • Dew Point Temperature
  • Globe Temperature
  • Headwind/Tailwind
  • Heat Load Index (HLI)
  • Heat Stress Index
  • Naturally Aspirated Wet Bulb Temperature        
  • Relative Humidity
  • Station Pressure (Absolute Pressure)
  • Temperature
  • Temperature-Humidity Index (THI) 
  • Wet Bulb Temperature (Psychrometric)
  • Wet Bulb Globe Temperature (WBGT)
  • Wind Chill
  • Wind Direction (Cardinal Points, Degrees)
  • Wind Speed



Cattle Specific Heat Stress Measurements and Models

THI - Temperature-Humidity Index
THI is calculated based on ambient temperature and relative humidity and has been extensively applied in research and management to represent the overall impact of moderate to hot conditions on cattle, especially those who are housed. Although THI is similar to the Heat Index typically reported in the local weather report, it is calculated differently. Accordingly, to obtain THI without a dedicated instrument, it is necessary to take a local temperature and humidity reading and refer to a reference table or perform calculations.

HLI – Heat Load Index
The limitation of THI is that is does not take into account sun, air flow, or accumulation effects. HLI is a more complete environmental index which includes temperature, relative humidity, and the additional parameters of solar radiation and wind speed. These added parameters are most important for assessing heat stress risk in exposed, unshaded cattle. These parameters are derived from the Globe Temperature – an advanced meteorological measurement which uses a heat-absorbing metal globe. Because Globe Temperature is not available on traditional weather stations, it has previously been difficult to implement management practices based on HLI.
AHLU – Accumulated Heat Load Units
AHLU is the most complete cattle heat stress model – addressing the fact that cattle accumulate heat load during prolonged heat events where they have insufficient environmental night cooling. THI and HLI alone may not predict the level of cattle heat stress because they do not address this accumulation impact.


Who’s Using?

  • Feedlots/Feedyards
  • Cow-Calf Operators
  • Backgrounding Operations
  • Dairy Producers
  • Processors
  • Veterinarians
  • Livestock Nutritionists
  • Transportation Providers
  • Researchers

 Kestrel DROP D2AG
Livestock Heat
Stress Monitor
Kestrel 5000AG
Meter with LiNK
Kestrel 5500AG
Agriculture Weather
Meter with LiNK
5400AG Cattle Heat Stress Tracker
Relative Humidityyesyesyesyes
Heat Stress Indexyesyesyesyes
Temperature Humidity Index (THI)yesyesyesyes
Dew Point Temp.yesyesyesyes
Wind Speed/Air Speed yesyesyes
Wind Chill yesyesyes
Wet Bulb Temp. (Psychrometric) yesyesyes
Station Pressure (Absolute Pressure) yesyesyes
Barometric Pressure yesyesyes
Altitude yesyesyes
Density Altitude yesyesyes
Volume Air Flow yesyes 
Wind Direction  yesyes
Crosswind / Headwind / Tailwind  yesyes
Delta T  yesyes
Globe Temp.   yes
Naturally Aspirated Wet Bulb Temp.   yes
Wet Bulb Globe Temp. (WBGT)   yes
Heat Load Index (HLI)   yes
Accumulated Heat Load Units (AHLU)   yes