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Monitoring Behavior and Welfare of Cattle in Response to Summer Weather in an Arizona Rangeland Pasture Using a Commercial Rumen Bolus
by
, and
Amadeus O. Barto
1, 
Derek W. Bailey
1,2,*,
Ly Ly Trieu
3,
Pippa Pryor
4,
Kieren D. McCosker
5 and
Santigo Utsumi
1 1
Animal & Range Sciences, New Mexico State University, Las Cruces, NM 88003, USA
2
Deep Well Ranch, Prescott, AZ 86304, USA
3
Computer Sciences, New Mexico State University, Las Cruces, NM 88003, USA
4
School of Agriculture and Food Sustainability, The University of Queensland, Gatton, QLD 4343, Australia
5
Centre of Animal Science, The University of Queensland, Gatton, QLD 4343, Australia
*
Author to whom correspondence should be addressed.
Animals 2025, 15(10), 1448; https://doi.org/10.3390/ani15101448 (registering DOI)
Submission received: 17 March 2025
/
Revised: 12 April 2025
/
Accepted: 10 May 2025
/
Published: 16 May 2025
(This article belongs to the Special Issue Real-Time Sensors and Their Applications in Smart Animal Agriculture)
Simple Summary
Monitoring the welfare of cattle on rangelands is logistically challenging, and hot weather can adversely affect animal health and productivity. The aim of this study was to evaluate the use of a commercially available rumen bolus (SmaXtec) to measure the body temperature and behavior of cattle grazing rangelands during the summer in Arizona. The cattle body temperature increased with higher wet bulb globe temperatures, an index used to monitor heat stress in humans. Cattle activity levels were most closely associated with relative humidity, surprisingly increasing at more humid levels. The estimated water intake of cattle decreased at higher humidity levels. The rumen bolus appears to be an effective tool for remotely monitoring cattle activity and body temperature while grazing extensive pastures.
Abstract
The effect of weather on the welfare of cattle grazing rangelands has received little study. The objective of this case study was to evaluate the effectiveness of a commercial rumen temperature bolus in monitoring changes in cattle body temperature and behavior during the summer on Arizona rangelands. Ten 2-year-old Corriente heifers were monitored by using SmaXtec Classic Boluses from 1 June to 29 August 2023. The bolus and weather data were averaged and analyzed on 3 and 24 h time scales. The bolus outputs included an activity index, a water intake index, the reticular temperature (RT) and the adjusted reticular temperature (ART, adjusted for drinking events). Weather metrics included the wet bulb globe temperature (WBGT), relative humidity (RH), ambient temperature (AT), wind speed, solar load and temperature–humidity index (THI). Weather variables were independently evaluated as a fixed continuous effect with linear, quadratic and cubic functions. The relative humidity and WBGT were better predictors of bolus metrics than other weather variables. Using 24 h data, the ART initially decreased by 0.4 °C as the WBGT increased from 2 °C to 15 °C, but the ART increased by over 0.15 °C with increasing WBGTs up to 24 °C. As the relative humidity increased, a proprietary bolus activity index initially increased with increasing RH to 45%, remained relatively constant until 65% RH and then increased at more humid levels. A proprietary water intake index decreased with increasing RH. Commercial rumen boluses have the potential to monitor body temperature and identify periods when cattle behavior may be affected by hot weather.
