Magnitude and persistence of higher estrus-associated temperatures in beef heifers and suckled cows

Higher estrus-associated temperatures (HEAT) are a hallmark feature in sexually active females. The overarching aim of this study was to characterize the variability, magnitude, and persistence of HEAT in heifers and suckled beef cows as well as identify associated factors when occurring during thermoneutral conditions at the onset of the spring breeding season. In both heifers and cows, estrus was induced using a 7-d controlled internal drug release (CIDR)-PGF2α protocol. Vaginal temperature after prostaglandin F2α administration was recorded every 5 min using a Thermochron iButton affixed to a blank CIDR (containing no progesterone). Estrus was defined as when a heifer first stood to be mounted or when a cow had an Estrotect patch score of 3 or 4. Level of HEAT varied among individual animals. When comparing common HEAT variables using a mixed model with date nested within a year, maximum HEAT (39.9 ± 0.1 and 40.0 ± 0.1 °C) and duration (15.5 ± 0.8 and 15.4 ± 0.7) were similar in heifers and cows, respectively. However, the magnitude and persistence of HEAT differed. Total area under the HEAT curve was 117.1 ± 13.5 and 158.7 ± 12.3 for heifers vs cows, respectively (P = 0.0571). Further, 42.9% of heifers and 49% of cows had maximum HEAT ≥ 40 °C which persisted up to 6.5 and 10 h, respectively. When ambient conditions were predominantly thermoneutral, temperature humidity index had minimal impact on HEAT (mixed model, repeated measures over time). Toward identifying associated factors with different aspects of HEAT using best fit hierarchical linear regression models, baseline vaginal temperature and baseline duration were the most highly associated independent variables. Follicle size, estradiol and progesterone levels, and other available animal-related variables (e.g., age, weight, hair coat score) explained only a small amount of variation in HEAT. In summary, level of HEAT varies in estrus females even under thermoneutral conditions. Because HEAT can persist for an extended time, direct effects on fertility important components are unavoidable. Whether HEAT is a good or bad component of the periovulatory microenvironment is the basis of ongoing and future studies.

Predicting labor onset relative to the estimated date of delivery using smart ring physiological data

The transition from pregnancy into parturition is physiologically directed by maternal, fetal and placental tissues. We hypothesize that these processes may be reflected in maternal physiological metrics. We enrolled pregnant participants in the third-trimester (n = 118) to study continuously worn smart ring devices monitoring heart rate, heart rate variability, skin temperature, sleep and physical activity from negative temperature coefficient, 3-D accelerometer and infrared photoplethysmography sensors. Weekly surveys assessed labor symptoms, pain, fatigue and mood. We estimated the association between each metric, gestational age, and the likelihood of a participant's labor beginning prior to (versus after) the clinical estimated delivery date (EDD) of 40.0 weeks with mixed effects regression. A boosted random forest was trained on the physiological metrics to predict pregnancies that naturally passed the EDD versus undergoing onset of labor prior to the EDD. Here we report that many raw sleep, activity, pain, fatigue and labor symptom metrics are correlated with gestational age. As gestational age advances, pregnant individuals have lower resting heart rate 0.357 beats/minute/week, 0.84 higher heart rate variability (milliseconds) and shorter durations of physical activity and sleep. Further, random forest predictions determine pregnancies that would pass the EDD with accuracy of 0.71 (area under the receiver operating curve). Self-reported symptoms of labor correlate with increased gestational age and not with the timing of labor (relative to EDD) or onset of spontaneous labor. The use of maternal smart ring-derived physiological data in the third-trimester may improve prediction of the natural duration of pregnancy relative to the EDD.

Digital infrared thermal imaging of udder skin surface temperature: a novel non-invasive technology to monitor calving process in Murrah buffalo (Bubalus bubalis)

Quantifiable decline in the maternal body temperature during the pre-calving offers the possibilities for predicting the calving that can improve the calving management. As infrared thermography (IRT) is a simple non-contact tool for precise measurement of surface temperature, we investigated the use of IRT to establish thermal signatures around calving in the Murrah buffalo. The IRT of eye, right lateral, left lateral and rear side of udder skin surface temperature (USST) were recorded at 6 h interval from 96 h before the expected date of calving, at the time of calving and 24 h post-calving in Murrah buffaloes (n = 28). In parallel, blood samples were collected for progesterone (P4) assay. The results revealed that the IRT of the eye, right and left lateral and rear side of USST showed a significant decrease in the temperature from 48 h pre-calving till the onset of calving with a ΔT (°C) of 0.56, 0.91, 0.70, and 0.90, respectively. Mean USST significantly declined from 48 h pre-calving with a ΔT of 0.85 °C. The residual temperature of both eye and various ROI of the udder also followed a similar and significant declining trend from 48 to 0 h of calving indicating that circadian influence on the USST was minimum. Plasma P4 concentration significantly decreased from 72 h pre-calving till calving. It is concluded that a marked reduction in the IRT of the USST at 6-12 h pre-calving would be useful in predicting the onset of calving in the Murrah buffalo.

Increased accuracy of estrus prediction using ruminoreticular biocapsule sensors in Hanwoo (Bos taurus coreanae) cows

Visual estrus observation can only be confirmed at a rate of 50%-60%, which is lower than that obtained using a biosensor. Thus, the use of biosensors provides more opportunities for artificial insemination because it is easier to confirm estrus than by visual observation. This study determines the accuracy of estrus prediction using a ruminoreticular biosensor by analyzing ruminoreticular temperature during the estrus cycle and measuring changes in body activity. One hundred and twenty-five Hanwoo cows (64 with a ruminal biosensor in the test group and 61 without biosensors in the control group) were studied. Ruminoreticular temperatures and body activities were measured every 10 min. The first service of artificial insemination used gonadotropin-releasing hormone (GnRH)-based fixed-time artificial insemination protocol in the control and test groups. The test group received artificial insemination based on the estrus prediction made by the biosensor, and the control group received artificial insemination according to visual estrus observation. Before artificial insemination, the ruminoreticular temperature was maintained at an average of 38.95 ± 0.05°C for 13 h (-21 to -9 h), 0.73°C higher than the average temperature observed at -48 h (38.22 ± 0.06°C). The body activity, measured using an indwelling 3-axis accelerometer, averaged 1502.57 ± 27.35 for approximately 21 h from -4 to -24 h before artificial insemination, showing 203 indexes higher body activity than -48 hours (1299 ± 9.72). Therefore, using an information and communication techonology (ICT)-based biosensor is highly effective because it can reduce the reproductive cost of a farm by accurately detecting estrus and increasing the rate of estrus confirmation in cattle.

Accuracy to Predict the Onset of Calving in Dairy Farms by Using Different Precision Livestock Farming Devices

Simple Summary

If the onset of calving can be accurately detected as well as appropriate calving assistance can be performed on a dairy farm, at that time, the prevalence of dystocia, stillbirth, vaginal laceration, retained fetal membranes, and consequent clinical metritis/endometritis can be decreased significantly. Therefore, in order to reduce these losses, our primary task must be to predict the onset of calving accurately and provide timely and professional calving assistance. This review focuses on the diagnostic possibilities and limitations of detecting the onset calving in the field.

Abstract

Besides traditional methods such as evaluation of the external preparatory and behavioral signs, which even presently are widely used also in large dairy farms, there are several new possibilities such as measuring body (intravaginal, ventral tail-base surface, ear surface, or reticulo-ruminal) temperature, detecting behavioral signs (rumination, eating, activity, tail raising) or detecting the expulsion of the device inserted into the vagina or fixed to the skin of the vulva when allantochorion appears in the vulva to predict the onset of the second stage of calving. Presently none of the single sensors or a combination of sensors can predict the onset of calving with acceptable accuracy. At the same time, with the exception of the iVET^® birth monitoring system, not only the imminent onset of calving could be predicted with high accuracy, but a significantly lower prevalence rate of dystocia, stillbirth, retained fetal membranes, uterine diseases/clinical metritis could be reached while calving-to-conception interval was significantly shorter compared with the control groups. These results may confirm the use of these devices in dairy farms by allowing appropriate intervention during calving when needed. In this way, we can reduce the negative effect of dystocia on calves and their dams and improve their welfare.

Positive relationship of rectal temperature at fixed timed artificial insemination on pregnancy outcomes in beef cattle

The overarching aim was to examine the relationship of rectal temperature at fixed time artificial insemination (FTAI) on pregnancy outcomes in a typical breeding season with expected pregnancy rates approaching 50% using Bos indicus and Bos taurus cattle. This represents a continuum of steps to test the hypothesis that elevated body temperature at or around insemination is functionally important to maximize pregnancy outcomes. Rectal temperature of Bos indicus cattle at FTAI ranged from 37.0 to 40.9 °C; 60.6% were hyperthermic. Positive factors impacting pregnancy outcomes were rectal temperature at FTAI, body condition, and estrus patch scores. Rectal temperature at FTAI was positively associated with pregnancy outcomes (P < 0.0001); per each 1 °C increase pregnancy odds increased 1.9 times (95% CI: 1.4 to 2.6). Highest pregnancy outcomes occurred with rectal temperatures exceeding 40 °C (P = 0.0004). Rectal temperature before FTAI in Bos taurus cattle ranged from 37.8 to 41.8 °C; 43.3% were hyperthermic. Factors impacting pregnancy were rectal temperature at FTAI, estrus activity, parity, and ambient conditions on day of FTAI. Rectal temperature of Bos taurus cattle at FTAI was positively associated with pregnancy (P = 0.0286); odds increased 1.45 times (95% CI: 1.0 to 2.0) per each 1 °C increase. Highest pregnancy outcomes occurred with rectal temperatures at FTAI exceeding 40 °C (P = 0.057). Moreover, positive relationship of rectal temperature at FTAI to pregnancy persisted in estrual females (71.25% of total; P = 0.0408; OR 1.5; 95% CI: 1.0 to 2.2). Mindful that 1) elevated temperatures observed in Bos indicus and Bos taurus cattle directly promote meiotic resumption of the oocyte in vitro and that 2) in vivo hyperthermia alters intrafollicular components which others have shown to potentiate ovulation and promote meiotic resumption, it is biologically plausible that an acute elevation in body temperature at or around time of insemination is functionally important to maximize pregnancy outcomes.

How to Predict Parturition in Cattle? A Literature Review of Automatic Devices and Technologies for Remote Monitoring and Calving Prediction

Cattle farming is facing an increase in number of animals that farmers must care for, together with decreasing time for observation of the single animal. Remote monitoring systems are needed in order to optimize workload and animal welfare. Where the presence of personnel is constant, for example in dairy farms with great number of lactating cows or with three milking/day, calving monitoring systems which send alerts during the prodromal stage of labor (stage I) could be beneficial. On the contrary, where the presence of farm personnel is not guaranteed, for example in smaller farms, systems which alert at the beginning of labor (stage II) could be preferred. In this case, time spent observing periparturient animals is reduced. The reliability of each calving alarm should also be considered: automatic sensors for body temperature and activity are characterized by a time interval of 6-12 h between the alarm and calving. Promising results have been shown by devices which could be placed within the vaginal canal, thus identifying the beginning of fetal expulsion and optimizing the timing of calving assistance. However, some cases of non-optimal local tolerability and cow welfare issues are reported. Future research should be aimed to improve Sensitivity (Se), Specificity (Sp) and Positive Predictive Value (PPV) of calving alert devices in order to decrease the number of false positive alarms and focusing on easy-to-apply, re-usable and well tolerated products.

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.

Assessment of Sensitivity and Profitability of an Intravaginal Sensor for Remote Calving Prediction in Dairy Cattle

One critical point of dairy farm management is calving and neonatal first care. Timely calving assistance is associated with the reduction of calf mortality and postpartum uterine disease, and with improved fertility in dairy cattle. This study aimed to evaluate the performance and profitability of an intravaginal sensor for the prediction of stage II of labor in dairy farms, thus allowing proper calving assistance. Seventy-three late-gestating Italian Holstein cows were submitted to the insertion of an intravaginal device, equipped with light and temperature sensors, connected with a Central Unit for the commutation of a radio-signal into a cell phone alert. The remote calving alarm correctly identified the beginning of the expulsive phase of labor in 86.3% of the monitored cows. The mean interval from alarm to complete expulsion of the fetus was 71.56 ± 52.98 min, with a greater range in cows with dystocia (p = 0.012). The sensor worked correctly in both cold and warm weather conditions, and during day- or night-time. The intravaginal probe was well tolerated, as any cow showed lesions to the vaginal mucosa after calving. Using sex-sorted semen in heifers and beef bull semen in cows at their last lactation, the economic estimation performed through PrecisionTree™ software led to an income improvement of 119 € and 123 €/monitored delivery in primiparous and pluriparous cows, respectively. Remote calving alarm devices are key components of "precision farming" management and proven to improve animal welfare, to reduce calf losses and to increase farm incomes.

Change of Ruminoreticular Temperature and Body Activity before and after Parturition in Hanwoo (Bos taurus coreanae) Cows

How do body temperature and activity change before and after parturition in pregnant cows? Changes in body temperature such as ruminal, rectal, and vaginal temperature during the parturition have been reported, but there are no results of the simultaneous observation of body temperature and activity. The aim of this study was to simultaneously confirm changes in the ruminoreticular temperature and body activity before and after parturition using the ruminoreticular bio-capsule sensor every 1 h. The 55 pregnant cows were used for the experiment, the ruminoreticular bio-capsule sensor was inserted and stabilized, and the ruminoreticular temperature and body activity were measured. The ruminoreticular temperature was lower by 0.5° from −24 h to −3 h in parturition compared to 48 h before parturition and then recovered again after parturition. Body activity increased temporarily at the time of parturition and 12 h after parturition. Therefore, the ruminoreticular temperature and body activity before and after parturition was simultaneously confirmed in pregnant cows.

Estrus Prediction Models for Dairy Gyr Heifers

Simple Summary

Intraruminal devices are already being used to predict reproductive events in cattle. For this prediction, several models and approaches can be used. The aim of this study was to evaluate changes in rumen reticulum temperature (RRT) and activity (ACT) during estrus in Dairy Gyr heifers and to evaluate different models for estrus prediction. There was an increase in both RRT and ACT in the estrus period compared to the same period on the day before and the day after estrus. Among the mathematical models, Random Forest had the best performance. The present results suggest that RRT and ACT can contribute to the identification of estrus and be of value for improving the reproductive efficiency of Zebu herds in tropical regions.

Abstract

Technological devices are increasingly present in livestock activities, such as identifying the reproductive status of cows. For this, predictive models must be accurate and usable in the productive context. The aims of this study were to evaluate estrus-associated changes in reticulo-rumen temperature (RRT) and activity (ACT) in Dairy Gyr heifers provided by reticulo-rumen boluses and to test the ability of different models for estrus prediction. The RRT and ACT of 45 heifers submitted to estrus synchronization were recorded using reticulo-rumen boluses. The means of RRT and ACT at different time intervals were compared between the day before and the day of estrus manifestation. An analysis of variance of RRT and ACT was performed using mixed models. A second approach employed logistic regression, random forest, and linear discriminant analysis models using RRT, ACT, time of day, and the temperature-humidity index (THI) as predictors. There was an increase in RRT and ACT at estrus (p < 0.05) compared to the same period on the day before and on the day after estrus. The random forest model provided the best performance values with a sensitivity of 51.69% and specificity of 93.1%. The present results suggest that RRT and ACT contribute to the identification of estrus in Dairy Gyr heifers.

Increased Ruminoreticular Temperature and Body Activity after Foot-and-Mouth Vaccination in Pregnant Hanwoo (Bos taurus coreanae) Cows

How does vaccination against foot-and-mouth disease (FMD) affect pregnant cows? Vaccination is the most effective method of preventing the spread of FMD, but it is linked to sporadic side effects, such as abortion and premature birth, which result in economic loss. In this study, ruminoreticular temperature and body activity were measured before and after FMD vaccination using a ruminoreticular biocapsule sensor in Hanwoo cows at different stages of pregnancy. Compared to the unvaccinated groups, the ruminoreticular temperature increased 12 h after vaccination in the vaccinated groups. This increase in temperature is significantly correlated to vaccination. Compared to the nonpregnant and early pregnancy groups, the ruminoreticular temperature of the late pregnancy group increased sharply by more than 40 °C. Moreover, in nonpregnant and early pregnancy groups, a rapid increase in body activity was observed after FMD vaccinations. Of the 73 pregnant vaccinated cows in the study, a total of five cases had side effects (four abortions and one premature birth). Therefore, changes in the ruminoreticular temperature and activity in pregnant cows can be used as raw data to further clarify the association of FMD vaccination with the loss of a fetus and possibly predict abortion, miscarriage, and premature birth following FMD vaccination.

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.

An attempt at estrus detection in cattle by continuous measurements of ventral tail base surface temperature with supervised machine learning

We aimed to determine the effectiveness of estrus detection based on continuous measurements of the ventral tail base surface temperature (ST) with supervised machine learning in cattle. ST data were obtained through 51 estrus cycles on 11 female cattle (six Holsteins and five Japanese Blacks) using the tail-attached sensor. Three estrus detection models were constructed with the training data (n = 17) using machine learning techniques (random forest, artificial neural network, and support vector machine) based on 13 features extracted from sensing data (indicative of estrus-associated ST changes). Estrus detection abilities of the three models on test data (n = 34) were not statistically different among models in terms of sensitivity and precision (range 50.0% to 58.8% and 60.6% to 73.1%, respectively). The relatively poor performance of the models might indicate the difficulty of separating estrus-associated ST changes from estrus-independent fluctuations in ST.

Influences on Infrared Thermography of the Canine Eye in Relation to the Stress and Arousal of Racing Greyhounds

Simple Summary

To improve the welfare of racing greyhounds, the identification of stressful industry practices is required. One potential method for monitoring stress in greyhounds is infrared thermography, which measures surface temperature. This article reports on the use of eye temperature, which may increase after a stressful event. The location on the eye that temperature is taken from is likely to be critical to the measurements. This study monitored 465 greyhounds racing at three racetracks in New South Wales. It found that the right eye and lacrimal caruncle (the inner corner of the eye) revealed temperature changes most effectively. Eye temperatures increased after racing, which may be due to physical exertion, stress and arousal. Additionally, eye temperature was higher in dogs that waited longer to race. Dogs at Richmond racetrack had lower eye temperatures before racing, but higher eye temperatures after racing compared to those at the Wentworth Park and Gosford racetrack. Other factors that increased eye temperature included humidity and a dog’s coat colour, age and final placing. Greyhounds that have light-coloured coats, are younger or placed poorly may be more stressed after racing. These factors need to be considered so that stress can be accurately detected.

Abstract

Infrared thermography (IRT) can be used to identify stressors associated with greyhound racing procedures. However, factors unrelated to stress may influence measurements. Validation of an eye side (right or left) and a reference point on the eye is required if IRT is to be standardised for industry use. Infrared images of greyhound heads (n = 465) were taken pre-racing and post-racing at three racetracks. Average temperature was recorded at seven different locations on each eye. A multivariate analysis model determined how several factors influenced eye temperature (ET) pre-racing and post-racing. As expected, ET increased after racing, which may be attributed to physical exertion, stress and arousal. The right eye and lacrimal caruncle had the highest sensitivity to temperature changes and could be considered reference points for future studies. Additionally, dogs that raced later had higher ET, and Richmond racetrack had the lowest pre-race ET, but the highest post-race ET. This may suggest that arousal increases as the race meet progresses and certain track attributes could increase stress. Furthermore, ET increased as humidity increased, and higher post-race ET was associated with light-coloured, young and low-performing dogs. Environmental and biological factors need to be considered if IRT is to become accurate in the detection of canine stress and monitoring of greyhound welfare.

Sensitivity and specificity of a tail-activity measuring device for calving prediction in dairy cattle

Efficient calving surveillance is essential for avoiding stillbirth due to unattended dystocia. Calving sensors can help detect the onset of parturition and thus ensure timely calving assistance if necessary. Tail-raising is an indicator of imminent calving. The objective of this study was to evaluate a tail-mounted inclinometer sensor (Moocall Ltd., Dublin, Ireland) and to monitor skin integrity after sensor attachment. Cows (n = 157) and heifers (n = 23) were enrolled at 275 d post insemination, and a sensor was attached to each cow's tail. Investigators checked for signs indicating the onset of stage II of parturition, verified the position of the sensor, and evaluated the skin integrity of the tail above and below the sensor hourly for 24 h/d. We used 5 different intervals (i.e., 1, 2, 4, 12, and 24 h until calving) to calculate sensitivity and specificity. Sensors continuously remained on the tail (i.e., within 3 cm of the initial attachment position) after initial attachment until the onset of calving in only 13.9% of animals (n = 25). Sensors were reattached until a calving event occurred (51.6%) or the animal was excluded for other reasons (34.4%). In 31 animals the sensor was removed because the tail was swollen or painful. Heifers were significantly less likely than cows to lose a sensor but more likely to experience tail swelling or pain. Depending on the interval preceding the onset of parturition, sensitivity varied from 19 to 75% and specificity from 63 to 96%.

Rumen-Reticular Temperature During Estrus and Ovulation Using Automated Activity Monitors in Dairy Cows

This study aimed to determine changes in rumen-reticular temperature (RRT) at estrus or ovulation and determine if these changes are associated with the intensity of estrous expression. Cows were equipped with an automated activity monitor (AAM) and a rumen-reticular bolus thermometer. A total of 190 estrus episodes were used where physical activity data was recorded using the AAM and ovulation was determined via ultrasonography of the ovaries at alert and twice daily, for a maximum of 60 h. Estrous expression was assessed using the maximum activity and duration in which activity remained above the AAM threshold; both characteristics were categorized using the median. Temperature data was collected for the duration of estrus, as well as for the interval of time where ovulation was determined to occur. Three measures of temperature were calculated: (1) positive area under the curve (AUC), (2) maximum positive temperature change (PTC), (3) maximum negative temperature change (NTC) at estrus (AUC_E/ PTC_E/ NTC_E) and around ovulation (AUC_O/PTC_O/ NTC_O). Both AUC and PTC were greater during estrus than around ovulation (2.7 ± 0.2 and 1.1 ± 0.3°C² for AUC_E and AUC_O; 0.55 ± 0.03 and 0.26 ± 0.04°C for PTC_E and PTC_O, respectively). In contrast, NTC was lower around ovulation than estrus (-0.28 ± 0.05 and -0.60 ± 0.06°C for NTC_E and NTC_O). Cows with greater estrous expression had greater AUC and PTC during estrus than around ovulation, but cows with lesser estrous expression had similar AUC and PTC. Increases in AUC [High THI (Temperature Humidity Index): High activity: 4.7 ± 0.5, Low activity: 1.5 ± 0.4; Low THI: High activity: 3.1 ± 0.2, Low activity: 1.4 ± 0.2 °C²] and PTC (High THI: High activity: 0.79 ± 0.08, Low activity: 0.36 ± 0.07; Low THI: High activity: 0.60 ± 0.04, Low activity: 0.47 ± 0.04°C) associated with estrous expression were found to be greater on days with higher THI. Alerts created using standard deviations from the mean were unable to detect estrus or ovulation with acceptable precision. Further research is required to determine how changes in RRT can be used successfully to predict estrus and ovulation.

Predictive potential of activity and reticulo-rumen temperature variation for calving in Gyr heifers (Bos taurus indicus)

Factors related to the thermal physiology and activity of Zebu animals close to calving are still unknown. The aims of this study were 1) to describe the pattern of reticulo-rumen temperature and activity variation in nulliparous Gyr heifers close to calving, and 2) to evaluate the predictive potential of these traits for calving in Gyr heifers. Forty pregnant Gyr heifers that had calved between August and December 2017 at the Getúlio Vargas Experimental Station, Empresa de Pesquisa Agropecuária de Minas Gerais (Epamig), Brazil, were used. The animals received a rumen bolus to monitor reticulo-rumen temperature (Trr) and activity (Act) at intervals of 10 min. Mixed linear models were used. A decrease in Trr and an increase in Act were observed on the days preceding calving. Differences in Trr and Act were more evident during the final 21 and 11 h previous to calving compared to 14 days before calving, measured at the same time of day. There was a decrease of about 0.20 °C in Trr at the time of calving when compared to baseline (14 days before calving measured at the same time of day). Environmental variables, such as temperature and air humidity, as well as biological factors such as circadian rhythm, may influence the interpretation of the data. In conclusion, variations exist in the Trr and Act of Gyr heifers in the hours before calving, which is preceded by a decrease in Trr and an increase in Act. Particularities in the thermal physiology of Zebu cattle must be considered when prediction devices previously validated only for European breeds are used.

Inline Reticulorumen pH as an Indicator of Cows Reproduction and Health Status

Our study hypothesis is that the interline registered pH of the cow reticulum can be used as an indicator of health and reproductive status. The main objective of this study was to examine the relationship of pH, using the indicators of the automatic milking system (AMS), with some parameters of cow blood components. The following four main groups were used to classify cow health status: 15-30 d postpartum, 1-34 d after insemination, 35 d after insemination (not pregnant), and 35 d (pregnant). Using the reticulum pH assay, the animals were categorized as pH < 6.22 (5.3% of cows), pH 6.22-6.42 (42.1% of cows), pH 2.6-6.62 (21.1% of cows), and pH > 6.62 (10.5% of cows). Using milking robots, milk yield, fat protein, lactose level, somatic cell count, and electron conductivity were registered. Other parameters assessed included the temperature and pH of the contents of reticulorumens. Assessment of the aforementioned parameters was done using specific smaX-tec boluses. Blood gas parameters were assessed using a blood gas analyzer (EPOC (Siemens Healthcare GmbH, Erlangen, Germany). The study findings indicated that pregnant cows have a higher pH during insemination than that of non-pregnant ones. It was also noted that cows with a low fat/protein ratio, lactose level, and high SCC had low reticulorumen pH. They also had the lowest blood pH. It was also noted that, with the increase of reticulorumen pH, there was an increased level of blood potassium, a high hematocrit, and low sodium and carbon dioxide saturation.

The Effect of Behaviour and Diet on the Rumen Temperature of Holstein Bulls

Rumen temperature boluses are becoming increasingly used as a means of monitoring core body temperature for the detection of ill health. However, the effect of behavior on rumen temperature is largely unknown. This research investigates the impact of behaviour and diet on the rumen temperature of Holstein bulls, both at grass, and in a housed environment. Rumen temperature was recorded at five-minute intervals using a bolus. Direct observations were conducted on young bulls in two studies (i) at grass (n = 30) and (ii) while housed (n = 32). In addition, activity monitors were attached to bulls at grass (n = 24). Within each study, diet differed by the level of concentrate supplementation. There was no effect of diet on rumen temperature. Significant differences in rumen temperature were observed between behaviour groups for bulls at grass (p < 0.001) and housed (p < 0.001). Furthermore, drinking resulted in the lowest rumen temperature (grass 35.97 °C; housed 36.70 °C). Therefore, rumen temperature is affected by behavior; however, the temperatures recorded were not outside the normal temperature range for healthy cattle.

Developing and evaluating threshold-based algorithms to detect drinking behavior in dairy cows using reticulorumen temperature

In this study, we assessed for the first time the use of a reticuloruminal temperature bolus and a thresholding method to detect drinking events and investigated different factors that can affect drinking behavior. First, we validated the detection of drinking events using 16 cows that received a reticuloruminal bolus. For this, we collected continuous drinking behavior data for 4 d using video recordings and ambient and water temperature for the same 4 d. After all the data were synchronized, we performed 2 threshold algorithms: a general-fixed threshold and a cow-day specific threshold algorithm. In the general-fixed threshold, a positive test was considered if the temperature of any cow fell below a fixed threshold; in the cow-day specific threshold, a positive test was considered when the temperature of specific cows fell below the threshold value deviations around the mean temperature of the cow for that day. The former was evaluated using a threshold varying between 35.7 and 39.5°C, and the latter using the formula μ-n10σ, where µ = mean of the temperature of each cow for one day, n = 1, 2, …, 20, and σ = standard deviation of the temperature of each cow on that day. The performance of the validation of detection using each of the threshold types was computed using different metrics, including overall accuracy, precision, recall (also known as sensitivity), F-score, positive predictive value, negative predictive value, false discovery rate, false omission rate, and Cohen's kappa statistic. The findings of the first study showed that the cow-day specific threshold of n = 10 performed better (true positives = 466; false positives = 167; false negatives = 165; true negatives = 8,416) than using a general-fixed threshold of 38.1°C (true positives = 449; false positives = 181; false negatives = 182; true negatives = 8,402). With the information gained in this first study, we investigated the different factors associated with temperature drop characteristics per cow: number of drops, mean amplitude of the drop, and mean recovery time. For this, we used data from 54 cows collected for almost 1 yr to build a mixed-effect multilevel model that included days in milk, parity, average monthly milk production, and ambient temperature as explanatory variables. Cow characteristics and ambient temperature had significant effects on drinking events. Our results provide a platform for automated monitoring of drinking behavior, which has potential value in prediction of health and welfare in dairy cattle.

Computer vision and remote sensing to assess physiological responses of cattle to pre-slaughter stress, and its impact on beef quality: A review

Pre-slaughter stress is well-known to affect meat quality of beef carcasses and methods have been developed to assess this stress. However, development of more practical and less invasive methods are required in order to assess the response of cattle to pre-slaughter stressors, which will potentially also assist with the prediction of beef quality. This review outlines the importance of pre-slaughter stress as well as existing and emerging technologies for quantification of the pre-slaughter stress. The review includes; i) indicators of meat quality and how they are affected by pre-slaughter stress in cattle, ii) contact techniques that have been commonly used to measure stress indicators in animals, iii) remotely sensed imagery techniques recently used as non-invasive methods to monitor physiological and behavioural parameters and iv) potential implementation of remotely sensed imagery data to perform contactless assessment of physiological measurements, which could be related to the pre-slaughter stress, as well as to the indicators of beef quality. Relevance to industry, conclusions and recommendations for research are included.

Reticulorumen temperature and pH as indicators of the likelihood of reproductive success

The temperature and pH of the contents of the reticulorumen of cattle can be monitored using sensors placed in a rumen bolus. In this research communication we test the hypothesis that these measurements can be used as a predictor of the likelihood of reproductive success. The study was performed on 20 Lithuanian Black and White dairy cows. The pH and temperature of the contents of their reticulorumens were measured using boluses manufactured for animal care (smaXtec animal care technology®). The data from reticulorumen were recording at 1 to 7 and 7 to 56 d post calving and then post insemination (on average 60 ± 12) until 170 d after calving. The pregnancies were tested with ‘Easy scan’ ultrasound 30–35 d after insemination. Those cows which were pregnant were assigned to the PD+ group (n = 12), and those which were not pregnant – assigned to the PD− group (n = 8). Rumen pH was initially lower in the PD+ group but then higher than in PD−, but temperature did not differ between the groups until after conception. We can conclude that cows with disturbed rumen metabolism (with low rumen pH) are less likely to conceive. The measurements of reticuloruminal pH may be useful as a predictor of the likelihood of reproductive success, but more research is needed before practical application.

Vaginal temperature measurement by a wireless sensor for predicting the onset of calving in Japanese Black cows

We evaluated the utility of the continuous measurement of vaginal temperature by a wireless sensor and wireless connection for predicting the onset of calving and for clarifying the relationships among dystocia, calf conditions, and temperature changes at a commercial beef cattle farm in Japan. A total of 625 effective delivery data was collected. The temperature sensor inserted to the vagina on 7 days before the expected due date and collected the vaginal temperature every 5 min. The sensor detected two alerts according to the temperature change, one was the vaginal temperature of 4 h moving average compared to the same time temperature of last two days decreased more than 0.4 °C (Alert 1) and the other was the rupture of the allantoic sac and the dropped sensor temperature reached to the ambient temperature (Alert 2). The detection rates of Alert 1 and Alert 2 were 88.3% and 99.4%, respectively. The average time between Alert 1 and Alert 2 (Time 1) was 22 h, and that between Alert 2 and delivery (Time 2) was 2 h. These results indicated that the continuous measurement of vaginal temperature is effective for predicting the calving time. The necessity of assistance was correlated with dystocia, calf birth weight (BW), sex, and gestation periods. Interestingly, the durations of Times 1 and 2 were also associated with dystocia. The calf BW, sex, and gestation periods affected the length of Time 2. Our findings indicate that the BW of the calf is the most important factor for dystocia risk, and that the continuous measurement of vaginal temperature could become a good indicator for predicting not only the onset of calving, but also the necessity of assistance.

Potential of connected devices to optimize cattle reproduction

Estrus and calving are two major events of reproduction that benefit from connected devices because of their crucial importance in herd economics and the amount of time required for their detection. The objectives of this review are to: 1) provide an update on performances reached by sensor systems to detect estrus and calving time; 2) discuss current economic issues related to connected devices for the management of cattle reproduction; 3) propose perspectives for these devices. The main physiological parameters monitored separately or in combination by connected devices are the cow activity, body temperature and rumination or eating behavior. The combination of several indicators in one sensor may maximize the performances of estrus and calving detection. An effort remains to be made for the prediction of calvings that will require human assistance (dystocia). The main reasons to invest in connected devices are to optimize herd reproductive performances and reduce labor on farm. The economic benefit was evaluated for estrus detection and depends on the initial herd performances, herd size, labor cost and price of the equipment. Major issues associated with the use of automated sensor systems are the weight of financial investment, the lack of economic analysis and limited skills of the users to manage associated technologies. In the near future, connected devices may allow a precise phenotyping of reproductive and health traits on animals and could help to improve animal welfare and public perception of animal production.

The efficiency of vaginal temperature measurement for detection of estrus in Japanese Black cows

Recently, weak estrous behavior was assumed to be the cause of a decline in breeding efficiency in cattle. The present study investigated the effect of measuring the vaginal temperature on the detection of estrus in Japanese Black cows. First, the effect of hormone administration to cows with a functional corpus luteum on the vaginal temperature was evaluated by continuous measurement using a temperature data logger. After 24 h of cloprostenol (PG) treatment, the vaginal temperature was significantly lower than on day 7 after estrus, and the low values were maintained until the beginning of estrus (P < 0.05). The cows that received PG and exogenous progesterone (CIDR) did not show a temperature decrease until the CIDR was removed. This finding suggested that the vaginal temperature change reflected the progesterone concentration. The rate of detection of natural estrus was lower for a pedometer than for the vaginal temperature (P < 0.05); synchronization of estrus resulted in a high estrus detection rate regardless of the detection method. In a subsequent experiment, the effect of vaginal temperature measurement and the use of a pedometer on estrus detection was evaluated in the cool and hot seasons. The average activities during non-estrus and the activity increase ratio (estrus/non-estrus) changed according to season (P < 0.01, P < 0.05). However, the average vaginal temperatures during estrus and non-estrus were not affected by season. The estrus detection rate of the pedometer was lower in summer and lower than that obtained using the vaginal temperature. These results indicated that vaginal temperature measurement might be effective for detecting estrus regardless of estrous behavior.

Pathophysiological evaluation of subacute ruminal acidosis (SARA) by continuous ruminal pH monitoring

Evaluation of the radio‐transmission pH‐measurement system for monitoring the ruminal pH and subacute ruminal acidosis (SARA) in cattle is described. This is done in order to reveal the possible application of this system for detection and pathophysiological research of SARA by continuous ruminal pH measurement. The possibility of using this system for assessment of the ruminal pH in SARA cattle, and the presence of negative correlation between the ruminal pH and ruminal temperature in heathy and SARA cattle were determined. In addition, the 16S rRNA gene pyrosequencing analysis showed that the ruminal microbial community was simpler in SARA cattle, and the bacterial numbers in SARA cattle were lower than those in healthy hay‐fed cattle. Concentrate feeding might have reduced the diversity of the ruminal microbial community. Changes in the ruminal microbial community of SARA cattle might be related to the changes in ruminal pH followed by the decrease in the number of some bacteria. Continuous monitoring of the ruminal pH using the radio‐transmission pH‐measurement system would be applied for detection and prevention of SARA in the field and pathophysiological research of SARA, including ruminal zymology and bacteriology, which have been determined previously by sampling of the ruminal fluid and measuring of ruminal pH.

Methods and on-farm devices to predict calving time in cattle

In livestock farming, accurate prediction of calving time is a key factor for profitability and animal welfare. The most accurate and sensitive methods to date for prediction of calving within 24 h are the measurement of pelvic ligament relaxation and assays for circulating progesterone and oestradiol-17β. Conversely, the absence of calving within the next 12-24 h can be accurately predicted by the measurement of incremental daily decrease in vaginal temperature and by the combination of pelvic ligament relaxation and teat filling estimates. Continuous monitoring systems can detect behavioural changes occurring on the actual day of calving, some of them being accentuated in the last few hours before delivery; standing/lying transitions, tail raising, feeding time, and dry matter and water intakes differ between cows with dystocia and those with eutocia. Use of these behavioural changes has the potential to improve the management of calving. Currently, four types of devices for calving detection are on the market: inclinometers and accelerometers detecting tail raising and overactivity, abdominal belts monitoring uterine contractions, vaginal probes detecting a decrease in vaginal temperature and expulsion of the allantochorion, and devices placed in the vagina or on the vulvar lips that detect calf expulsion. The performance of these devices under field conditions and their capacity to predict dystocia require further investigation.

Using rumen probes to examine effects of conjugated linoleic acids and dietary concentrate proportion on rumen pH and rumen temperature of periparturient dairy cows

The study aimed to examine the influence of supplemented conjugated linoleic acids (CLA) to periparturient cows receiving different concentrate proportions antepartum on rumen pH (RpH) and rumen temperature (RT). Twenty pregnant German Holstein cows were equipped with rumen probes for continuous RpH and RT measurement in a frequency of 15 min to investigate effects of dietary concentrate and CLA around parturition and the impact of parturition itself on RpH and RT. Cows had ad libitum access to partial mixed rations, 3 weeks prior to calving until day 7 post-partum. Antepartum, cows received 100 g/day control fat (CON) or CLA supplement, either in low (20%; CON-20, CLA-20) or high concentrate diet (60%; CON-60, CLA-60). Post-partum, concentrate proportion was adjusted to 50% while fat supplementation continued. Compared with adapted feeding, high concentrate proportions antepartum tended to increase DMI and reduced RpH. Groups CON-60 and CLA-60 spent more than 4 h per day below RpH 5.6 during late pregnancy, indicating the presence of subacute rumen acidosis (SARA). The RT remained unaffected antepartum. Before calving, cows spent less time below RpH 5.6 and SARA could be detected in each group post-partum. Mean RpH increased slightly antepartum, whereas few hours before parturition a sharp decrease in RpH could be observed, accompanied with increased RT. Overall, it seems that CLA supplementation influences RpH and RT. Bearing in mind that rumen parameters fluctuate during day and herd level must be known, rumen probes for continuous RpH and RT measurement could be a useful management tool for animal health surveillance and may also help to predict parturition.

Maintenance energy requirements of beef cows and relationship with cow and calf performance, metabolic hormones, and functional proteins

Gestating Angus, nonlactating, spring-calving cows were used to determine variation in maintenance energy requirements (MR); to evaluate the relationship among MR and cow and calf performance, plasma concentrations of IGF-I, T4, glucose, insulin, and ruminal temperature; and to describe the LM proteome and evaluate protein abundance in cows with different MR. Cows (4 to 7 yr of age) with a BCS of 5.0 ± 0.2 and BW of 582 ± 37 kg in the second to third trimester of gestation were studied in 3 trials (trial 1, n = 23; trial 2, n = 32; trial 3, n = 38). Cows were individually fed a complete diet in amounts to meet predicted MR (Level 1 Model of NRC), and feed intake was adjusted weekly until constant BW was achieved for at least 21 d (maintenance). Cows were classified on the basis of MR as low (>0.5 SD less than mean, LMR), moderate (±0.5 SD of mean, MMR), or high (>0.5 SD more than mean, HMR) MR. Blood samples were taken at maintenance and at 2 mo postpartum in trial 2. Muscle biopsies were taken from LMR and HMR after cows consumed actual MR for 28 d (trial 2) or 21 d (trial 3). Proteins from LM were separated by 2-dimensional difference gel electrophoresis and were identified, and abundance was quantified and compared. The greatest differences in MR between cows were 29%, 24%, and 25% in trials 1, 2, and 3, respectively. Daily MR (NEm, kcal·BW(-0.75)·d(-1)) averaged 89.2 ± 6.3, 93.0 ± 4.9, and 90.4 ± 4.6 in trials 1, 2, and 3, respectively. Postpartum BW and BCS, calf birth and weaning weights, postpartum luteal activity, and ruminal temperature were not influenced by MR of the cows. Concentrations of IGF-I were greater (P = 0.001) in plasma of MMR compared with LMR cows consuming predicted MR diets, and MR was negatively correlated with concentrations of IGF-I in plasma (r = -0.38; P = 0.05) at 2 mo postpartum. A total of 103 proteins were isolated from LM; 52 gene products were identified. Abundance of specific proteins in the LM was not influenced (P > 0.11) by MR. Variation in MR of cows will make it possible to improve feed efficiency by selection. Identification of biomarkers for MR will allow selection of more efficient cows, which consume less feed and produce calves with similar weaning weights. Productive cows that require less feed for maintenance will improve efficiency of production and enhance sustainability of the environment.

Endogenous and exogenous progesterone influence body temperature in dairy cows

Three experiments were conducted to determine the effect of endogenous progesterone (P4) on body temperature comparing lactating, pregnant with lactating, nonpregnant cows, and to study the effect of exogenous P4 administered via a controlled internal drug release (CIDR) insert on body temperature in lactating dairy cows. Body temperature was measured vaginally and rectally using temperature loggers and a digital thermometer, respectively. In experiment 1, 10 cyclic lactating cows (3 primiparous, 7 multiparous) and 10 lactating, pregnant cows (3 primiparous, 7 multiparous) were included. Vaginal temperatures and serum P4 concentrations were greater in pregnant cows (vaginal: 0.3±0.01°C; P4: 5.5±0.4 ng/mL) compared with nonpregnant cows. In experiment 2, estrous cycles of 14 postpartum healthy, cyclic, lactating cows (10 primiparous, 4 multiparous) were synchronized, and cows were assigned randomly to 1 of 2 treatments (CIDR-P4 or CIDR-blank). A temperature logger was inserted 1 d after ovulation using a P4-free CIDR (CIDR-blank) and a CIDR containing 1.38g of P4 (CIDR-P4) in the control (n=7) and the P4-treated group (n=7), respectively. On d 3 after P4 treatment, vaginal temperature was 0.3±0.03°C greater compared with that on d 1 and d 5. In experiment 3, 9 cyclic multiparous lactating cows were enrolled 1±1 d after confirmed ovulation and a temperature logger inserted. Two days later, a CIDR-P4 was inserted on top of the CIDR-blank. On d 5±1 and d 7±1, respectively, the CIDR-P4 and CIDR-blank with the temperature logger were removed. During the CIDR-P4 treatment (48h), vaginal temperature was 0.2±0.05°C and 0.1±0.05°C greater than during the pre- and post-treatment periods (48h), respectively. Serum P4 concentration peaked during CIDR-P4 treatment (2.2±0.8 ng/mL) and was greater than during the pre-treatment period (0.2±0.2 ng/mL) for 48h. An increase in vaginal temperature could be due to endogenous and exogenous P4. However, a correlation between serum P4 concentrations and body temperature did not exist. Further investigations are warranted to better understand the pathways of the thermogenic effect of P4 on body temperature.

Relationship between pH and temperature in the ruminal fluid of cows, based on a radio-transmission pH-measurement system

To assess the relationship between pH and temperature in the ruminal bottom fluid, circadian changes were monitored using cows fed a control diet (C diet) or a rumen acidosis-inducing diet (RAI diet) by using a wireless radio-transmission pH- measurement system. These two parameters were measured simultaneously at 10-min intervals on day 14 after commencement of feeding. Compared to the mean ruminal pH for 60 min immediately after the morning feeding (0 hr), significantly lower pH was noted 3-13 hr later (P<0.05) and 4-19 hr later (P<0.01) in cows fed the C and RAI diets, respectively, although the reduction in the latter was much higher than that in the former. In contrast, significantly higher ruminal temperature was found at 8 and 12-14 hr later (P<0.05) and 6, 8, and 10-19 hr later (P<0.01) in cows fed the C and RAI diets, respectively. A significant negative correlation was observed between the lowest ruminal pH and its corresponding ruminal temperature in cows fed the C and RAI diets (r=-0.722 and -0.650, P<0.01, respectively), suggesting active fermentation and volatile fatty acid production in the rumen. However, ruminal pH profiles may not be predictable by measuring only ruminal temperature because decreases in ruminal pH were preceded by increases in ruminal temperature, and circadian changes in pH and temperature were associated with ruminal fermentation.