Relationship between Rectal Temperature and Vaginal Temperature in Grazing Bos taurus Heifers

Physiology Value of Breath, Pulse and Body Temperature of Cattle

Body temperature, respiratory rate, and pulse rate are required as the basis for determining the health status of cows. This study aims to measure the respiratory rate, pulse rate and body temperature of healthy beef cattle. A total of 25 mixed-breed beef cattle aged more than 1.5 years were used in this study. All cows were physically examined, their breath, and pulse frequency per minute were calculated, and their body temperature was measured by measuring rectal and vaginal temperature. The results showed that all the cows examined were in good health, characterized by a good appetite, and had normal activities. Cows had a respiratory rate of 20 ‒ 44 times/minute with an average of 32.6 ± 6.8 times/minute, and a pulse frequency of 76 ‒ 96 times/minute with an average of 84.2 ± 5.4 times/minute. Measurement of body temperature of cows per vagina was 37.9 ‒ 39.4 °C with a mean of 38.53 ± 0.42 °C, while per rectal showed 37.7 ‒ 39.2 °C with a mean of 38.49 ± 0.38 °C. The results of temperature measurements using the two methods did not show a significant difference. It was concluded that the respiratory rate of 20 ‒ 44 times/minute, pulse frequency of 76 ‒ 96 times/minute, and body temperature of 37.7 ‒ 39.4°C were the physiological parameters of the healthy mixed-breed cow.

Automated Monitoring of Cattle Heat Stress and Its Mitigation

Climate change related global warming is likely to continue, despite all mitigation measures taken by humans, due to the lag effect of long-term anthropogenic activities. Warming of the atmosphere can impact worldwide cattle production directly by compromising health, welfare and productivity, and indirectly by reducing the quality and quantity of animal feed. Under warm thermal conditions, cattle adjust their physiological and behavioural responses as an integral part of thermoregulation to maintain internal body temperature within a safe range. However, a greater intensity and duration of heat exposure can exceed thermoregulatory capacity leading to an increase in internal body temperature beyond the normal limit that ultimately evokes different animal responses to heat. In cattle, response to heat stress can be visually observed as elevated respiration rate or panting, but continuous visual monitoring is labour intensive, time consuming and subjective. Therefore, different weather-based indices have been developed such as the temperature humidity index (THI) and heat load index (HLI) which are commonly used weather-based indices for monitoring cattle heat stress at commercial level. However, the thermal comfort level of cattle based on weather-based indices has limited use at a microclimatic and individual animal level. Varying sensor-based approaches have shown promise to shift the focus of heat stress management to the individual level. Monitoring individual animal response and mitigation strategies for isolated heat-susceptible cattle could save on heat management costs whilst improving animal welfare and productivity. Here we review the technologies that enable automatic, continuous, and real-time cattle heat stress monitoring and mitigation under commercial conditions. Future platforms for autonomous monitoring and mitigation of heat stress in cattle are likely to be based on minimally-invasive smart technologies either singly, or in an integrated system, enabling real-time solutions to animal responses under various production systems and environmental conditions.

Vaginal temperature before calving assessed with wireless vaginal temperature sensor in dairy and beef cattle

We evaluated the daily and hourly vaginal temperature changes and the relationships between the dams' breed and parity by using a commercially available vaginal temperature sensor in 72 Holstein (Hol) calvings and 101 Japanese Black (JB) calvings. Vaginal temperature sensors inserted 7-10 days before the expected calving day sounded two alerts: when the temperature fell below the threshold (Alert 1), and when the sensor reached the ambient temperature after falling out of the dam's vagina with the rupture of the allantoic sac (Alert 2). The durations from Alert 1 to Alert 2 (Time 1) and from Alert 2 to delivery (Time 2) were calculated. Only Time 1 in the Hol group tended to be affected by parity and parity × calf body weight. In the JB group, none of the factors examined affected Time 1 or Time 2. The alert detection rates did not differ by parity in either breed or by the temperature threshold in Hol. However, the Hol group's alert detection rate was significantly lower than the JB group's (p < 0.05). The daily average temperature was higher in the Hol group and the primiparous dams than those in the JB and multiparous dams; it increased slightly from Day -7 to -3 (Day 0 = the day of calving) and then dropped dramatically on Days -1 and 0. The hourly vaginal temperature difference from -48 h of calving showed a typical pattern, i.e., a decrease from -30 h of Alert 1 and an increase at -6 h of Alert 1. The decrease and increase might be the regression of the pregnant corpus luteum and the beginning of the contractions, respectively. The temperature differences were significantly affected by parity and calving ease (p < 0.01). The primiparous dams showed wider temperature differences compared to the multiparous dams in both breeds (p < 0.001). No typical temperature difference pattern was observed in assisted calving or dystocia. The alert detection rate, the Time durations, and the vaginal temperature differences were affected by the dams' breed and parity. However, measuring vaginal temperatures proved useful for predicting the calving regardless of the breed and parity. The effect of calving ease remains unclear due to the low number of assisted calvings herein.

Investigations on the vaginal temperature, cycle stages, and steroid hormone concentrations during the breeding season in camels (Camelus dromedarius)

Background and Aim:

Estrus detection plays a crucial role in the success of animal reproduction. It was previously reported that body temperature changes during estrus. This study aimed to investigate the relationship between vaginal temperatures (VTs) measured by a data logger, ovarian activity, and hormonal cyclic changes in camels.

Materials and Methods:

Six mature, healthy, non-pregnant dromedary, and 10-12-year-old camels were included in the study. The ovarian activity was monitored with ultrasonography, and estrus behavior was evaluated using an active and virile male camel. Animals were inserted with a blank controlled internal drug release device attached with an intravaginal data logger. Every hour, the ambient temperature was recorded by another data logger. Blood samples were collected, and sera were used to measure estradiol and progesterone levels.

Results:

The whole follicular cycle lasted 25.41±1.36 days, and the maximum sizes of the dominant follicle in the first and second follicular waves were 1.63±0.27 cm and 1.94±0.42 cm, respectively. There was a significant positive correlation between the follicular diameter and estradiol-17b level (p<0.01, r=0.397). There was no correlation between the follicular diameter and progesterone level (p>0.05, r=0.038), which remained low during the whole period of the experiment. The mean daily VT was significantly correlated with the diameter of the dominant follicle (1.7-2.2 cm, p<0.01, r=0.52).

Conclusion:

Measurement of VT will improve the accuracy of estrus prediction. Further studies are recommended to validate VT in camel reproduction.

Recent Advances on Early Detection of Heat Strain in Dairy Cows Using Animal-Based Indicators: A Review

In pursuit of precision livestock farming, the real-time measurement for heat strain-related data has been more and more valued. Efforts have been made recently to use more sensitive physiological indicators with the hope to better inform decision-making in heat abatement in dairy farms. To get an insight into the early detection of heat strain in dairy cows, the present review focuses on the recent efforts developing early detection methods of heat strain in dairy cows based on body temperatures and respiratory dynamics. For every candidate animal-based indicator, state-of-the-art measurement methods and existing thresholds were summarized. Body surface temperature and respiration rate were concluded to be the best early indicators of heat strain due to their high feasibility of measurement and sensitivity to heat stress. Future studies should customize heat strain thresholds according to different internal and external factors that have an impact on the sensitivity to heat stress. Wearable devices are most promising to achieve real-time measurement in practical dairy farms. Combined with internet of things technologies, a comprehensive strategy based on both animal- and environment-based indicators is expected to increase the precision of early detection of heat strain in dairy cows.

A Multi-Disciplinary Approach to Assess the Welfare Impacts of a New Virtual Fencing Technology

Virtual fencing involving the application of audio cues and electrical stimuli is being commercially developed for cattle. Virtual fencing has the potential to improve productivity through optimized pasture management and utilization by grazing animals. The application of virtual fencing initiates public concern for the potential welfare impacts on animals due the aversive nature of using an electrical stimulus. It is therefore important to provide welfare assurance of the impacts of virtual fencing on livestock. In this paper, we provide an overview of the welfare assessment and validation stages for virtual fencing which could be applied to other new technologies utilizing novel systems. An understanding of stress measures and their suitability for use in specific contexts is discussed, including the use of glucocorticoids to measure both acute and chronic stress, and behavioral responses and patterns to indicate welfare states. The importance of individual differences in relation to learning and cognition are also highlighted. Together, this multi-disciplinary approach to welfare assessment provides a tool kit that may be applied for welfare assurance of some new technologies and systems for farm animals.

Methods to quantify heat stress in ruminants: Current status and future prospects

The physiology of hyperthermia or heat stress in mammals is complex. It is a totally systemic condition that in varying degrees involves all organs, tissues and body fluid compartments. The nature and magnitude of the response is influenced by animal specific characteristics (e.g. age, diet, body condition, gender, reproductive stage), environment and animal management. Given the multifaceted nature of heat stress, and the varied ruminant production systems based in varied geoclimatic zones, it has been difficult to find appropriate measures of heat stress for production ruminants. This has become an urgent challenge as production systems intensify globally in a warming climate. Bioclimatic indices such as the Temperature-Humidity Index (THI) have evolved to incorporate some measure of animal physiology. However, these indices do not have strong relationships with core temperature trajectories and altered respiratory dynamics of animals with excessive heat load. In recent decades, the careful physiology studies of the 1950-80s, have given way to numerous studies trialling a plethora of new technologies and computational approached to measure heat stress. Infrared thermography of body surface temperatures, automated measures of respiration rate and radiotelemetry of internal body temperatures are the most intensively researched. The common goal has been to find the 'holy grail' decision-making threshold or timepoint as to the animal's wellbeing. Are we making any progress?

Relaxing Effect of Hydrogen Sulfide on Isolated Bovine Mesenteric Lymph Nodes

We studied the effects and mechanisms of action of NaHS, an H₂S donor, on isolated phenylephrine-precontracted bovine mesenteric lymph nodes. NaHS induced concentration-dependent relaxation of lymph nodes. Removal of the endothelium reduced, but did not abolish the relaxing effect of NaHS. The relaxing effect was reduced by NO synthase inhibitor L-NAME, soluble guanylate cyclase inhibitor ODQ, ATP-sensitive K⁺ channel blocker glibenclamide, and a combination charybdotoxin+apamin (blockers of small- and intermediate-conductance Ca²⁺-activated K⁺ channels). Thus, the relaxing effect of H₂S on lymph nodes is mediated by several parallel mechanisms. H₂S induces relaxation of LN and modulates the rate of lymph transport, thereby affecting the development of immune processes in the body.

Welfare of beef cattle in Australian feedlots: a review of the risks and measures

The rising global demand for animal protein is leading to intensification of livestock production systems. At the same time, societal concerns about sustainability and animal welfare in intensive systems is increasing. This review examines the risks to welfare for beef cattle within commercial feedlots in Australia. Several aspects of the feedlot environment have the potential to compromise the physical and psychological welfare of cattle if not properly monitored and managed. These include, but are not limited to, animal factors such as the influence of genetics, temperament and prior health, as well as management factors such as diet, pen design, resource provision, pregnancy management, and stock-person attitudes and skills. While current industry and producer initiatives exist to address some of these issues, continuous improvements in welfare requires accurate, reliable and repeatable measures to allow quantification of current and future welfare states. Existing measures of welfare are explored as well as proxy indicators that may signal the presence of improved or reduced welfare. Finally, potential future measures of welfare that are currently under development are discussed and recommendations for future research are made.

Evaluating rumen temperature as an estimate of core body temperature in Angus feedlot cattle during summer

This study was conducted to determine the relationship between rectal temperature (T_REC) and rumen temperature (T_RUM) and to assess if T_RUM could be used as a proxy measure of core body temperature (T_CORE) in feedlot cattle. Eighty Angus steers (388.8 ± 2.1 kg) were orally administered with rumen temperature boluses. Rumen temperatures were recorded at 10-min intervals over 128 days from all 80 steers. To define the suitability of T_RUM as an estimation of T_CORE, T_REC were obtained from all steers at 7-day intervals (n = 16). Eight feedlot pens were used where there were 10 steers per pen (162 m²). Shade was available in each pen (1.8 m²/animal; 90% solar block). Climatic data were recorded at 30-min intervals, including ambient temperature (T_A; °C); relative humidity (RH; %); wind speed (WS; m/s) and direction; solar radiation (SR; W/m²); and black globe temperature (BGT; °C). Rainfall (mm) was recorded daily at 0900 h. From these data, temperature humidity index (THI), heat load index (HLI) and accumulated heat load (AHL) were calculated. Individual 10-min T_RUM data were converted to an individual hourly average. Pooled mean hourly T_RUM data from the 128-day data were used to establish the diurnal rhythm of T_RUM where the mean minimum (39.19 ± 0.01 °C) and mean maximum (40.04 ± 0.01 °C) were observed at 0800 h and 2000 h respectively. A partial correlation coefficient indicated that there were moderate to strong relationships between T_RUM and T_REC using both real-time (r = 0.55; P < 0.001) and hourly mean (r = 0.51; P < 0.001) T_RUM data. The mean difference between T_REC and T_RUM was small using both real-time (0.16 ± 0.02 °C) and hourly mean T_RUM (0.13 ± 0.02 °C) data. Data from this study supports the hypothesis that T_RUM can be used as an estimate of T_CORE, suggesting that T_RUM can be used to measure and quantify heat load in feedlot cattle.