Can changes in nasal temperature be used as an indicator of emotional state in cows?

Pasture access and eye temperature in dairy cows

Pasture access can benefit dairy cows' behavior, health, and welfare, but herds are increasingly housed indoors full-time. Recent infrared thermal-imaging (thermography) studies suggest that higher eye temperatures may be a physiological indicator of chronic stress. We, therefore, hypothesized that, compared to cows with pasture access, cows housed indoors full-time would have higher eye temperatures. In a two-phase crossover experiment, 29 Holstein-Friesian dairy cows experienced 18 days of overnight pasture access and 18 days of full-time indoor housing. We measured each animal's eye temperature 16 times (eight/phase). During Phase One, cows with pasture access had higher eye temperatures than cows housed indoors full-time (contrary to our hypothesis). However, during Phase Two, cows with pasture access had lower eye temperatures than cows housed indoors full-time. It is, therefore, unclear whether eye temperature reflected disparities in dairy cow welfare between different housing treatments.

Non-invasive assessment of positive affective state using infra-red thermography in rats

With recent increased focus on positive welfare in animal welfare science, there is demand for objective positive welfare indicators. It is unclear whether changes in body surface temperature can be used to non-invasively identify and quantify positive states in mammals. We recorded continuous measurements of tail surface temperature using infra-red thermography (IRT) and concurrent behavioural observations in male and female Wistar rats (Rattus norvegicus). If tail surface temperature can differentiate between positive and negative experiences, we expect a qualitatively different response compared to negative experiences. Three groups of rats were presented with increasing magnitudes of food rewards (neutral/none, one and three rewards). The rats were placed in an arena to which they were habituated and filmed for 30 s before and 30 min after exposure to different rewards. Tail temperature initially decreased from the pre-reward baseline and subsequently returned towards baseline temperature. The overall pattern of the change was the same as for rats subjected to negative stimuli in previous studies. Nevertheless, dynamic changes in tail temperature, specifically the rate of recovery and the behavioural response (exploration), differed between neutral and rewarded rats but failed to distinguish reward magnitude. Sex differences were found in both thermal and behavioural responses, unrelated to reward magnitudes. Female rats exhibited a greater initial response with a slower recovery than male rats, emphasising the value of using of both sexes in animal welfare research. This study improves our understanding of the effects of positive emotions induced by food reward on peripheral body temperature and behaviour.

Infrared thermography as a non-invasive method for evaluating stress in lactating dairy cows during isolation challenges

The overall objective of the current data report was to evaluate and test the feasibility of using infrared thermography (IRT) as a non-invasive method for measuring stress signs in lactating dairy cows during short negative challenges, such as visual isolation from herd-mates. The study was carried out at the Experimental Farm of the Research and Development Institute for Bovine Romania, on 20 Holstein-Friesian lactating multiparous dairy cows, between August and September 2022. Cows were housed in two identical tied stanchion barns (170/85 cm), and were isolated individually from the herd for 240 min post-morning milking. Our results shown significant (p ≤ 0.05) rises for both orbital and nasal IRT temperatures following the isolation challenge, suggesting that such approaches could represent adequate tools for assessing social stress in cattle. Overall, current results are in accordance with previous studies which validated both eye and nasal regions as IRT thermal windows for studying the effects of painful and negative contexts on stress response in farmed ruminants, while considering the stress-induced hyperthermia as an integral part of the physiological response to negative stimuli, as well as the current limitations that this tool faces.

Body surface temperature of rats reveals both magnitude and sex differences in the acute stress response

Understanding how biological markers of stress relate to stressor magnitude is much needed and can be used in welfare assessment. Changes in body surface temperature can be measured using infrared thermography (IRT) as a marker of a physiological response to acute stress. While an avian study has shown that changes in body surface temperature can reflect the intensity of acute stress, little is known about surface temperature responses to stressors of different magnitudes and its sex-specificity in mammals, and how they correlate with hormonal and behavioural responses. We used IRT to collect continuous surface temperature measurements of tail and eye of adult male and female rats (Rattus norvegicus), for 30 minutes after exposure to one of three stressors (small cage, encircling handling or rodent restraint cone) for one minute, and cross-validated the thermal response with plasma corticosterone (CORT) and behavioural assessment. To obtain individual baseline temperatures and thermal responses to stress, rats were imaged in a test arena (to which they were habituated) for 30 seconds before and 30 minutes after being exposed to the stressor. In response to the three stressors, tail temperature initially decreased and then recovered to, or overshot the baseline temperature. Tail temperature dynamics differed between stressors; being restrained in the small cage was associated with the smallest drop in temperature, in male rats, and the fastest thermal recovery, in both sexes. Increases in eye temperature only distinguished between stressors early in the response and only in females. The post stressor increase in eye temperature was greater in the right eye of males and the left eye of females. In both sexes encircling may have been associated with the fastest increase in CORT. These results were in line with observed behavioural changes, with greater movement in rats exposed to the small cage and higher immobility after encircling. The female tail and eye temperature, as well as the CORT concentrations did not return to pre-stressor levels in the observation period, in conjunction with the greater occurrence of escape-related behaviours in female rats. These results suggest that female rats are more vulnerable to acute restraint stress compared to male rats and emphasise the importance of using both sexes in future investigations of stressor magnitude. This study demonstrates that acute stress induced changes in mammalian surface temperature measured with IRT relate to the magnitude of restraint stress, indicate sex differences and correlate with hormonal and behavioural responses. Thus, IRT has the potential to become a non-invasive method of continuous welfare assessment in unrestrained mammals.

Infrared thermography as a tool for the measurement of negative emotions in dairy cows

In commercial dairy cows, the conditions in which they are kept may lead to negative emotional states associated with the development of chronic physiological and behavioural abnormalities that may compromise their health, welfare and productivity. Such states include fear, stress or anxiety. Behavioural rather than physiological tests are more likely to be used to indicate these states but can be limited by their subjectivity, need for specialised infrastructure and training (of the operator and sometimes the animal) and the time-consuming nature of data collection. Popularly used physiological measures such as blood cortisol may be more appropriate for acute rather than chronic assessments but are easily confounded, for example by a response to the act of measurement per se. More sophisticated physiological measures such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) may be impractical due to cost and time and, like blood cortisol, have the confounding associated with the act of measurement. By contrast, infrared thermography of external body surfaces is remote, non-invasive, easily repeated and follows an objective methodology, allowing longitudinal data acquisition for the inference of changes in chronic emotional state over time. The objective of this review was to investigate the potential of infrared thermography to measure cow emotions. In lactating dairy cows, maximum IRT of the eyes and coronary band of the limbs seem to be most representative of thermoregulatory changes, which are repeatable and correlate with behavioural and physiological indicators of emotional state. IRT methodologies have the potential to become a fundamental tool for the objective assessment of welfare state in dairy cows.

Positive Welfare Indicators in Dairy Animals

Nowadays, there is growing interest in positive animal welfare not only from the view of scientists but also from that of society. The consumer demands more sustainable livestock production, and animal welfare is an essential part of sustainability, so there is interest in incorporating positive welfare indicators into welfare assessment schemes and legislation. The aim of this review is to cite all the positive welfare indicators that have been proposed for dairy animals in theory or practice. In total, twenty-four indicators were retrieved. The most promising are exploration, access to pasture, comfort and resting, feeding, and behavioral synchronicity. Qualitative behavioral assessment (QBA), social affiliative behaviors, play, maternal care, ear postures, vocalizations, visible eye white, nasal temperature, anticipation, cognitive bias, laterality, and oxytocin have been also studied in dairy ruminants. QBA is the indicator that is most often used for the on-farm welfare assessment. Among all dairy animals, studies have been performed mostly on cattle, followed by sheep and goats, and finally buffaloes. The research on camel welfare is limited. Therefore, there is a need for further research and official assessment protocols for buffaloes and especially camels.

Towards a Positive Welfare Protocol for Cattle: A Critical Review of Indicators and Suggestion of How We Might Proceed

Current animal welfare protocols focus on demonstrating the absence (or at least low levels) of indicators of poor welfare, potentially creating a mismatch between what is expected by society (an assurance of good animal welfare) and what is actually being delivered (an assurance of the absence of welfare problems). This paper explores how far we have come, and what work still needs to be done, if we are to develop a protocol for use on commercial dairy farms where the aim is to demonstrate the presence of positive welfare. Following conceptual considerations around a perceived “ideal” protocol, we propose that a future protocol should be constructed (i) of animal-based measures, (ii) of indicators of affective state, and (iii) be structured according to indicators of short-term emotion, medium-term moods and long-term cumulative assessment of negative and positive experiences of an animal's life until now (in contrast to the current focus on indicators that represent different domains/criteria of welfare). These three conditions imposed the overall structure within which we selected our indicators. The paper includes a critical review of the literature on potential indicators of positive affective states in cattle. Based on evidence about the validity and reliability of the different indicators, we select ear position, play, allogrooming, brush use and QBA as candidate indicators that we suggest could form a prototype positive welfare protocol. We emphasise that this prototype protocol has not been tested in practice and so it is perhaps not the protocol itself that is the main outcome of this paper, but the process of trying to develop it. In a final section of this paper, we reflect on some of the lessons learnt from this exercise and speculate on future perspectives. For example, while we consider we have moved towards a prototype positive welfare protocol for short-term affective states, future research energy should be directed towards valid indicators for the medium and long-term.

Evaluating the accuracy of facial expressions as emotion indicators across contexts in dogs

Facial expressions potentially serve as indicators of animal emotions if they are consistently present across situations that (likely) elicit the same emotional state. In a previous study, we used the Dog Facial Action Coding System (DogFACS) to identify facial expressions in dogs associated with conditions presumably eliciting positive anticipation (expectation of a food reward) and frustration (prevention of access to the food). Our first aim here was to identify facial expressions of positive anticipation and frustration in dogs that are context-independent (and thus have potential as emotion indicators) and to distinguish them from expressions that are reward-specific (and thus might relate to a motivational state associated with the expected reward). Therefore, we tested a new sample of 28 dogs with a similar set-up designed to induce positive anticipation (positive condition) and frustration (negative condition) in two reward contexts: food and toys. The previous results were replicated: Ears adductor was associated with the positive condition and Ears flattener, Blink, Lips part, Jaw drop, and Nose lick with the negative condition. Four additional facial actions were also more common in the negative condition. All actions except the Upper lip raiser were independent of reward type. Our second aim was to assess basic measures of diagnostic accuracy for the potential emotion indicators. Ears flattener and Ears downward had relatively high sensitivity but low specificity, whereas the opposite was the case for the other negative correlates. Ears adductor had excellent specificity but low sensitivity. If the identified facial expressions were to be used individually as diagnostic indicators, none would allow consistent correct classifications of the associated emotion. Diagnostic accuracy measures are an essential feature for validity assessments of potential indicators of animal emotion.

The Effects of Vehicle Type, Transport Duration and Pre-Transport Feeding on the Welfare of Sheep Transported in Low Temperatures

Low temperatures can provide a risk to the welfare of sheep during transport because of increased ventilation chilling the sheep, and we examined the importance of three factors-covering the vehicle, duration of transport, and feeding prior to transport-on the welfare of sixty transported 4-month-old Dorper × Mongolian female sheep in a cold climate. Sheep in a covered vehicle had greater increases in head and ear temperatures than those in an open vehicle. Sheep transported for 2 h increased their leg temperatures, whereas those transported for 1 h had reduced leg temperatures. Increases in non-esterified fatty acids (NEFA) and lactate dehydrogenase (LDH) in the blood samples during the long transport suggested that sheep had more muscular and metabolic activity, compromising their well-being. Feeding prior to transport did not affect body temperatures, but those not fed prior to transport had reduced alanine transferase, HSP and cortisol in their blood, whereas those that were fed had reduced NEFAs, LDH and creatine kinase. Prior feeding had no effect on the sheep temperature indices over a two-hour transport period. Thus, the sheep most at risk of the adverse effects of cold temperatures were those transported in open vehicles, those transported for a longer time, and those not fed before transport.

Non-Invasive Physiological Indicators of Heat Stress in Cattle

Cattle are susceptible to heat stress, especially those kept on high levels of nutrition for the purpose of maximising growth rates, which leads to a significant heat increment in their bodies. Consequences include compromised health and productivity and mortalities during extreme events, as well as serious economic loss. Some measures of heat stress, such as plasma cortisol and temperature in the rectum, vagina, or rumen, are invasive and therefore unlikely to be used on farms. These may cause additional stress to the animal due to handling, and that stress in itself can confound the measure. Consequently, it is desirable to find non-invasive alternatives. Panting score (PS), cortisol metabolites in faeces, milk, or hair, and the infrared temperature of external body surfaces are all potentially useful. Respiratory indicators are difficult and time consuming to record accurately, and cortisol metabolites are expensive and technically difficult to analyse. Infrared temperature appears to offer the best solution but requires further research to determine the thresholds that define when corrective actions are required to ensure optimal health and productivity. Research in this area has the potential to ultimately improve the welfare and profitability of cattle farming.

Where Do We Stand in the Domestic Dog ( Canis familiaris ) Positive-Emotion Assessment: A State-of-the-Art Review and Future Directions

Although there have been a growing number of studies focusing on dog welfare, the research field concerning dog positive-emotion assessment remains mostly unexplored. This paper aims to provide a state-of-the-art review and summary of the scattered and disperse research on dog positive-emotion assessment. The review notably details the current advancement in dog positive-emotion research, what approaches, measures, methods, and techniques have been implemented so far in emotion perception, processing, and response assessment. Moreover, we propose possible future research directions for short-term emotion as well as longer-term emotional states assessment in dogs. The review ends by identifying and addressing some methodological limitations and by pointing out further methodological research needs.

A sampling strategy for the determination of infrared temperature of relevant external body surfaces of dairy cows

Infrared thermography is a tool to investigate the welfare of cattle. This study aimed to identify a sampling strategy for recording infrared thermograms in dairy cows, in order to most efficiently determine biologically relevant changes in the maximum infrared temperature (IRT) of the eyes and coronary band of forelimbs. Thirty-one dairy cows were used for the study. They were assessed with four replicates of thermograms for each of the head and lower forelimb per cow for 6 mostly consecutive days (sessions). The data obtained were subjected to random effects Analysis of Variance which was used to estimate the variance components for this sampling model, using maximum IRT of both eyes; (left + right eye)/2 and both limbs; (left + right coronary band of forelimb)/2 as dependant variables. The variance components were used to calculate least significant differences (LSD) between two theoretical treatment groups under different sampling scenarios. Analysis showed that there was minimal improvement in precision beyond 2 thermograms within a session but there was improvement with increasing the number of sessions from 2 to 3. The LSD of both eyes and both limbs reached a biologically relevant difference (0.4 and 0.9 °C, respectively) at a minimum number of 14 - 16 cows monitored for 2 consecutive thermography sessions, or 10 - 12 cows for 3 sessions. We conclude that no more than 2 replicate IRT measures are required per session but that measuring on 3 consecutive days should be considered, depending on whether time or number of cows used is the primary limitation.

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.

Symposium review: Scientific assessment of affective states in dairy cattle

Affective states, which refer to feelings or emotions, are a key component of animal welfare, but these are also difficult to assess. Drawing upon a body of theoretical and applied work, we critically review the scientific literature on the assessment of affective states in animals, drawing examples where possible from research on dairy cattle, and highlighting the strengths and weaknesses of scientific methods used to assess affective states in animals. We adopt the "valence/arousal" framework, describing affect as a 2-dimensional space (with valence referring to whether an experience is positive or negative, and arousal referring to the intensity of the experience). We conclude that spontaneous physiological and behavioral responses typically reflect arousal, whereas learned responses can be valuable when investigating valence. We also conclude that the assessment of affective states can be furthered using mood assessments and that the use of drug treatments with known emotional effects in humans can be helpful in the assessment of specific affective states in animals.

The Impact of 'Selfie' Tourism on the Behaviour and Welfare of Brown-Throated Three-Toed Sloths

Simple Summary

The use of wild animals as photo props is a potential animal welfare concern that is prevalent across Latin America. The present study documents animal welfare concerns associated with the use of wild caught brown-throated three-toed sloths (Bradypus variegatus) for wildlife ‘selfies’ by tourists at three locations in Manaus, Brazil and Puerto Alegria and Iquitos in Peru. Between 4 October 2016 and 8 April 2017 researchers attended 34 tours, where 17 sloths were observed. The sloths were; (1) held on average by 5 people (during each observation); (2) frequently exposed to physical manipulation of the head and/or limbs; and (3) frequently held by their claws. During handling the sloth’s behaviour was also analysed; we found that the two behaviours performed for the longest average duration of time were surveillance (55.3%) and limb stretching (12.6%). Further validation is needed; however, it is possible that some of the behaviours displayed may be indicators of fear, stress and anxiety. Our results describe behaviours exhibited by sloths, which have previously never been documented in any published literature, the data therefore serves as a potential baseline for future study.

Abstract

The use of wild animals as photo props is prevalent across the globe and is widely recognised to represent a potential animal welfare concern. However, detailed information regarding the specific impacts of such activity on wild animal behaviour is currently lacking. Herein, we investigated how brown-throated three-toed sloths (Bradypus variegatus) were handled by tourists, and how sloths behaved during wildlife ‘selfies’ taken in Manaus, Brazil and Puerto Alegria and Iquitos in Peru. In total, we observed 17 sloths (during 70 focal observations) that were provided for use in wildlife selfies on 34 different tours. We found that an average number of 5 people held each sloth during each focal observation. For 48.6% of the time the sloths were handled in a way which involved physical manipulation of the sloths’ head and/or limbs and/or being held by the claws. From the eight different types of sloth behaviour observed, we found that the two types performed for the longest average duration of time were surveillance (55.3%) and limb stretching (12.6%). Our findings show that when being handled sloths were frequently held in ways that may compromise their welfare. Although to date the behaviour of sloths while being handled has not been reported in any published literature, in this study we document certain behaviours which may act as indicators of compromised welfare. We suggest that our data provides a potential baseline for future study into the behaviour and welfare of sloths.