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Automated collection of heat stress data in livestock: new technologies and opportunities †,1–3 †,1 ‡ †,|| †,|| James E. Koltes, Dawn A. Koltes, Benny E. Mote, John Tucker, and Don S. Hubbell, III † ‡ Department of Animal Science, University of Arkansas, Fayetteville, AR 72701; Department of Animal || Science, University of Nebraska, Lincoln, NE 68583-0908; and Livestock and Forestry Research Station, Division of Agriculture, Batesville, AR 72501 Key words: automated phenotyping technologies, cattle, heat stress, pig, precision livestock technologies, thermosensors © The Author(s) 2018. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact firstname.lastname@example.org Transl. Anim. Sci. 2018.2:319–323 doi: 10.1093/tas/txy061 temperature is among the mostly commonly used INTRODUCTION measurement of body temperature. Additional indi- Body temperature is among the most eco- cators of heat stress include respiration rate (Collier nomically important phenotypes in livestock ani- et al., 2006), sweating rate (Dikmen et al., 2014), mals as it is tied to health, reproductive success, and blood flow measurement ( Honig et al., 2016). and productivity (St-Pierre et al., 2003; Duff These types of measurements are very labor inten- and Galyean, 2007). Heat stress was estimated sive to collect. Automated phenotyping could pro- result in $1.7 to 2.4 billion in losses in the live- vide temperature data in real time that would allow stock industry in 2003 (St-Pierre et al., 2003), immediate intervention to prevent animal health– which is likely an underestimate of today’s losses. related losses. Animals may have elevated body temperature The objective of this manuscript is to discuss due to illness, injury, heat stress, toxin exposure, automated body temperature monitoring technol- or other health-related issues. Unfortunately, it is ogies and to discuss their use to develop new strate- only after we observe elevated body temperature gies to overcome potential animal health problems. that we can mitigate the effects of these stressors. Herein, we compared and contrasted several dif- Development of technologies to detect elevated ferent automated technologies for temperature temperature earlier or to predict and prevent the monitoring. Rather than trying to discuss all negative effects of a fever or heat stress would be devices that exist, the discussion below attempts to extremely valuable. capture the majority of available technology types. Traditional measures of temperature and indi- Implications and potential uses for current tech- cators of elevated body temperature have been used nologies were discussed with particular emphasis to identify sick and heat-stressed animals (Duff in detection and prevention of heat stress. and Galyean, 2007; Burdick et al., 2012). Rectal Corresponding author: email@example.com Invited presentation at the Research Technology Received April 4, 2018. Symposium held at the ASAS-CSAS Annual Meeting, Accepted May 16, 2018. Baltimore, MD on July 10, 2017. Current Address: Department of Animal Science, Iowa State University, Ames, IA 50011–1178 Downloaded from https://academic.oup.com/tas/article-abstract/2/3/319/4999824 by Ed 'DeepDyve' Gillespie user on 31 July 2018 320 Koltes et al. AUTOMATED TEMPERATURE DETECTION the junction between the rumen and reticulum. Among the advantages of this data type is that it DEVICES can be transmitted wirelessly to data readers. In addition, while these devices are not reading data, Temperature-Sensing Ear Tags (Tympanic/Ear they can act as a data logger to keep short-term Canal Sensors) amounts of data to then transmit in batches when near a receiving antenna. These devices are sensitive A number of different, but related, ear temper- in reading body temperature but impacted by water ature monitoring systems have been developed for volume, feed intake levels, and rumen microorgan- use in cattle (Cow Manager BV, Gerverscop, NL; isms (Davis et al., 2003; Burdick et al., 2012). In fact, DoggTag, Herddogg systems, Longmont, CO; rumen temperatures tend to run around 2 °C higher Fever Tags, Amarillo, TX; SenseTag, Quantified Ag, than rectal temperatures due to heat produced by Lincoln, NE; TekVet Health Monitoring System, microbes in the rumen. One downfall of data from East Palmetto, FL). Among the most well-known rumen boluses is that it is limited to set time dur- ear temperature–sensing devices are the Fever Tag ation that the sensors will continue to transmit data system (Fever Tags, Amarillo, TX). These devices are before they stop recording and transmitting infor- mounted on the ear and have a temperature sensor mation (roughly 150 d or until the battery fails). The that is placed within the ear canal to measure body boluses can only be used one time and require add- temperature (for application, see Richeson et al. itional equipment to capture the data. (2011)). Examples of applications have been used primarily for detection of fever due to illness (i.e., bovine respiratory disease; McCorkell et al., 2014), Intravaginal and Intrarectal Thermosensor Devices but these tags could also be used to monitor heat Vaginal temperature measurements have been stress. These devices flash a light out of the ear in a suggested to be extremely sensitive to picking up way that is meant to be visible from a distance when changes in body temperature, based on studies in observing the head of an animal. To get an accurate humans (Emmanuel et al., 2000). In cattle, it appears reading, it is critical that these devices are properly that the ability to detect fever or other tempera- inserted into the ear canal so that the temperature ture changes was nearly identical when comparing probe is retained in the correct position (Davis et al., automated rectal and vaginal temperature sensors 2003). In addition, environmental factors such as (Burdick et al., 2012). Vaginal thermosensors appear sun exposure could impact temperature readings, to work well to detect increased body temperature in particularly if the sensor is not maintained in the response to LPS treatment, which mimics inflamma - correct position. Studies seeking to use these ear tion and fever (Burdick et al., 2012). Multiple vaginal temperature–sensing devices to identify animals at thermosensor technologies have been used in cattle, the onset of fever have had mixed results (Richeson including iButtons (Maxim Integrated, San Jose, et al., 2011; McCorkell et al., 2014). Most of these CA) and Hobo (Onset Co.) sensors. These devices technologies transmit data wireless for remote use. can log considerable amounts of data but lack the In addition to collecting temperature data, many ability to transmit the data wirelessly. Examples of of the automated technologies record activity data side-by-side applications were conducted previously using a 3-axis accelerometer to quantify animal (Dikmen et al., 2014). One challenge with implanta- movements. Accelerometer information can also be ble sensors is that the size of the device may dictate useful for predicting rumination in cattle, and could its application in some species, making some tech- also be used to identify an animal hanging it’s head nologies (i.e., iButtons) handy for use in animals of lower during an illness. For more information on smaller size, such as heifers, pigs, sheep, and goats, similar ear temperature–sensing technologies, see compared with bulkier devices. Burdick et al. (2012) Davis et al., (2003) and Foulkes et al., (2013). and Davis et al. (2003) also considered automated indwelling rectal temperature measurement probe Rumen-Reticular Boluses and determined that these devices have similar sen- sitivity to the less invasive vaginal probes. Despite Rumen boluses have the potential to pro- their more invasive nature, indwelling rectal temper- vide many types of information about ruminants, ature probes may be the most accurate and sensitive including rumen pH, rumen temperature, and activ- alternative for measuring body temperature in male ity (Smaxtec animal care GmbH, Graz, Austria; animals for research purposes. However, stability Alzahal et al., 2011). These devices when placed in of rectal probes, the influence of fecal temperature, cattle are actually located in the reticulum or near Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/319/4999824 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Automated temperature monitoring in livestock 321 and keeping them stationary may be limitations in thermal imaging has been used to attempt to pre- collecting accurate indwelling sensor temperature dict heat stress (Salles et al., 2016; Unruh et al., data (McCafferty et al., 2015). Additional infor- 2017). In beef cattle, infrared thermography was mation on indwelling rectal probes can be found successful at identifying heat-stressed animals but in Reuter et al. (2010). Vaginal thermosensors can could not identify animals at risk of heat stress be used multiple times and require relatively little early in the day (Unruh et al., 2017). Information equipment for downloading data to a computer. about the best location to measure temperature has been defined in dairy cattle. Thermal images taken from the forehead were most closely related to rec- Additional Wearable and Implantable Devices tal temperature in Jersey cattle, while right and left A variety of implantable devices are also flank were mostly closely related to the calculated available for temperature sensing, and new wear- thermal humidity index (THI; Salles et al., 2016). able technologies are constantly being developed. Recently, hand-held thermal imaging devices have Devices have been developed for implantation been tested as an alternative approach to capture around the rumen in cattle, which could be placed thermal images (Vogel et al., 2016). The best areas in other areas throughout the body (Alzahal et al., to achieve accurate and consistent measurements 2007). Microchip devices have been tested in pigs may vary slightly from species to species. At this to sense body temperature, some of which can be time, it is uncertain how factors like UV light read easily through radiotelemetry with a wand. might impact thermal images. Ambient tempera- Microchip technologies to measure body temper- ture can impact the observed animal temperatures ature in pigs have been found to generally corres- (Soerensen and Pedersen, 2015). Thermal cameras pond well to rectal temperature, typically ranging can cost a few thousand to tens of thousands of at 1 °C lower than the rectal measurement (Lohse dollars and require considerable time to review et al., 2009; Jara et al., 2016). Many similar types the images unless software is available to filter and of implantable devices have been developed, but review the data. For additional information on all require invasive procedures to place the device thermal imaging technologies, see Soerensen and within animals. Kou et al. (2017) recently described Pedersen (2015) and Neethirajan (2017). a method of measuring body surface temperature with a new wearable device worn on the leg of Critical Factors in Comparing and Utilizing cattle. The method, which measures temperature Automated Thermosensing Technologies at close contact to the muscle, was reported to be In order to be able to use thermosensing data in highly correlated to rectal temperature. Additional real time to make management decisions, a number information on wearable devices can be found in of important factors should be considered. Data the following review (Neethirajan, 2017). collection needs to be truly automated. Data trans- mission through radio telemetry (wirelessly) is crit- Thermal Imaging ical for getting up-to-date information on individual Thermal imaging holds great promise in animals. Sensitivity and variability of temperature detecting a combination of temperature and measurements are important considerations. The behavioral data that is likely related to heat and frequency of measurement in which these devices disease stress. To use thermal imaging on a large collect data is also an important consideration. In scale, software-based assignment of body tem- some cases, having data more often is advantageous perature would be extremely helpful but requires to observe acute variation, but in other cases, more considerable computation (Sellier et al., 2014). frequent temperature observations may be unin- Development of this software is a rapidly evolv- formative because temperatures may not deviate or ing area. Determining where to mount cameras to factors like water consumption may impact tempera- get the best images and where to take the thermal ture readings. Furthermore, in the case of image and images of the animal are important considerations. video data, data reduction may be more important A large number of body areas have been used as because of the huge data storage requirements that references to get consistent and accurate body tem- can exceed 2 Tb of hard drive space per week, per peratures, with varying results in pigs (Soerensen camera. Environmental factors and measurement and Pedersen, 2015). Measurements at the eye location on the animal can also impact the accuracy, and base of the ear appear to work best in swine, sensitivity, and variability of temperature measure- though there is considerable variability. In cattle, ments. Thus, monitoring local ambient temperature, Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/319/4999824 by Ed 'DeepDyve' Gillespie user on 31 July 2018 322 Koltes et al. humidity, and airspeed are important factors in eval- SUMMARY AND CONCLUSIONS uating automated data collection. The ability to pre- Automated phenotyping technologies to meas- vent stress due to animal handling, which can elevate ure body temperature provide new opportunities to temperature, and reduced invasiveness of the technol- manage livestock. Due to large animal-to-animal ogy are additional important consideration (Curley variation, measurement at the animal level would et al., 2006; Burdick et al., 2012). Technologies that be useful to manage heat stress and disease. Current reduce the need for human intervention may there- costs of some technologies may make them prohibi- fore provide more accurate assessment of body tem- tive for use on commercial farms but allow research perature. Ease of configuring these technologies in that can inform producers on how best to man- facilities or on animal (i.e., in a stable, easy to iden- age or select for animals with improved heat tol- tify anatomical location) is also important. All of erance and potentially disease resistance. Wireless these technologies will likely have challenges with data transmission, availability of suitable internet animal-to-animal variation in stable body tempera- network speed, and capacity to transfer data may ture, making it difficult to declare a common activa - provide challenges in capturing this data in some tion threshold to declare a fever or heat stress in all locations. Future development of these technol- animals. Use of individual animal temperature data ogies will require real-time data collection, data over time is likely needed to set individual specific management, and development of predictive mod- body temperature thresholds. Costs of these technol- els to determine the risk of heat and disease stress ogies and tradeoffs in their measurement accuracy in to allow for early intervention to prevent or limit comparison with rectal temperature (i.e., the current losses in current and future generations of animals. gold standard) will also guide which technologies will provide the most helpful information to prevent LITERATURE CITED heat stress and disease-related losses. Alzahal, O., H. Alzahal, M. A. Steele, M. Van Schaik, I. Kyriazakis, T. F. Duffield, and B. W. McBride. 2011. The use of a radiotelemetric ruminal bolus to detect body FUTURE APPLICATIONS IN LIVESTOCK temperature changes in lactating dairy cattle. J. 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