Technical note: Device for measuring respiration rate of cattle under field conditions1

Abstract

Respiration rate (RR) is 1 of the physiological responses used to gauge the level of heat stress in cattle. Respiration rate is usually measured by counting chest movement of the animal. This procedure has some disadvantages including that the person who is doing the counting must be trained to ensure accurate results, the animals must be preconditioned to the presence of the observer, and the presences of the observer may influence the behavior and activity of the animals or their position in the pen. In this study, a device that continuously records RR without restraining the animal was developed. The device is lightweight, cheap, easy to install, and more importantly, does not interfere with the activities of the animal. The device is mounted in a halter and is placed around the neck of the subject. The device measures air temperature near the nostrils of the animal and RR is calculated as the number of oscillations of the temperature. The RR measured by the device were compared against RR observed by counting the flank movement (for 60 s, repeated every 10 min) of 5 Nellore cattle, 1 animal per d, and the results show no statistical difference ( = 0.45) between the 2 methods. This demonstrates that this device can be used to continuously measure RR of cattle under field conditions.

Technical note: Development of a noninvasive respiration rate sensor for cattle

“…The most common method to measure the RR in cattle is to count the flank movements visually (Milan et al, 2016); however, this method is time-consuming and labor-intensive. The continuous measurement of RR in long-term studies is difficult to implement, can be physically strenuous, and inevitably results in miscounts.…”

“…Methods have been developed to measure the RR automatically. Milan et al (2016) developed a device that monitors changes in temperature near the nostrils with a thermistor. Its advantage is the continuous recording of RR, but this method does not provide information about the strength of exhaled and inhaled pressure, which in turn can provide important information about breathing patterns (e.g., shallow as well as deep breathing), which can give information about stressful situations.…”

“…The animal or other animals may try to move the belt. This can result in signal interference or sensor damage (Milan et al, 2016). In addition, Pastell et al (2007) developed a system to measure RR via a laser distance sensor during milking.…”

“…With repeated analysis of the video recordings or direct observations beside the animals, these missing breaths could be identified. In accordance, Milan et al (2016), who also used the nasal cavity to measure RR, showed both fewer breaths (n = 4) and more breaths (n = 1) counted by the sensor (thermistor) in comparison to the visual counting, whereby no differentiation between different body positions was done. It should also be considered that counting inhalations and exhalations may be a more precise approach compared with counting flank movements, which can be triggered by other causes.…”

“…Thus, the sensor value appears to be the more reliable measure compared with the visual method due to the position of the sensor in the nasal cavity, where the pressure sensor really measures the inhalations and exhalations of the air into or out of the lung. Misinterpretation in counting RR (e.g., triggered by movement or very shallow breathing) can be avoided and error rates (e.g., due to untrained observers; Milan et al, 2016) reduced. This is an advantage in contrast to previous studies, where the abdominal movement was measured via chest belt or laser (Pastell et al, 2007) to record the RR.…”