Influence of the Environment on Body Temperature of Racing Greyhounds

Thermal relations in sled dogs before and after exercise

Regulation of internal body temperature (Tb), or thermoregulation, is an evolutionarily conserved trait that places demand on basal metabolic rate of endothermic animals. Across species, athletes generate increased quantities of heat in comparison to their nonathletic counterparts and, therefore, must mediate physiological unbalance by upregulating the effectiveness of their heat dissipation abilities. Canine athletes are no exception to this phenomenon, however, with literature denoting body temperatures lower than nonathletic canines, it is clear they must possess adaptations to mitigate this demand. With VO2 max measurements of more than 200 mL/kg/min in sled dogs with mild training to 300 mL/kg/min in highly trained animals, sled dogs are a prime example of athleticism in canines. Seeking to determine correlations between Tear and body mass, morphology, and age of canine athletes, core body temperature (Tb) was measured with an instant ear thermometer, using Tear as a correlate before and after a 2-mile run. In addition, we employed thermal imaging analysis to capture body-wide heat dissipation patterns in sled dogs, and focused on thermal variation of mouth (Tmouth), nose (Tnose), and eyes (Teye). Furthermore, we looked at correlations between thermal variability across these four tissues and head morphology of each dog. Tear was consistently the highest temperature across all tissues measured, with a 1.5°C increase between pre- to postexercise (p < 0.001). Thermal imaging revealed significant positive correlations between Tmouth and body mass 15 min postexercise (p = 0.0023) as well as significantly negative correlations between Tnose and body mass at before exercise (p = 0.0468), Teye and nose length after run (p = 0.0076), and Tmouth and nose length after run (p = 0.0110). As body temperature rises during exercise, it becomes increasingly important to regulate blood flow throughout the body to supply working tissues with oxygen. This demand is offset by the role of the snout in evaporative cooling through panting, functioning as a prime location for heat dissipation and therefore maintaining significant relationships with many other vascularized tissues.

Infrared Thermography in Assessment of Facial Temperature of Racing Sighthound-Type Dogs in Different Environmental Conditions

The aim of the study was to assess the usefulness of IRT measurements of selected regions of interest (ROI), i.e., the eyeball and the nose of whippet dogs, before and after coursing competitions taking place in various environmental conditions, thereby enabling the assessment of well-being and the level of heat stress. The research was carried out over two different periods with different thermal humidity indexes (THIs). In the first period, the THI was 59.27 (Run 1), while in the second period, the THI was 63.77 (Run 2). The experimental subjects comprised 111 sighthound-type dogs-whippets-that were photographed with a thermal imaging camera to determine their eye temperature (ET) and nose temperature (NT). The average minimum and maximum eye temperatures were statistically lower after running in both measurements. Increased minimum and maximum nose temperatures were also demonstrated after both runs. The nasal temperature values were statistically higher for Run 2, for which the THI was higher, compared to Run 1. Eyeball temperature may be a marker of thermoregulation ability, regardless of the ambient temperature. The value of ETmax decreased on average by 2.23 °C and 0.4 °C, while NTmax increased uniformly by 2 °C after both runs. A correlation was found between the IRT measurements and physiological indicators.

Canine detection of explosives under adverse environmental conditions with and without acclimation training

Canines are one of the best biological detectors of energetic materials available; however, canine detection of explosives is impacted by a number of factors, including environmental conditions. The objectives of this study were: 1) determine how canine detection limits vary when both the canine and odorant are tested in varying temperature and humidity conditions (canine and odor interactive effects); and 2) determine if an acclimatization plan can improve detection limits in an adverse environmental condition. Eight working line canines were trained to detect four energetics: prill ammonium nitrate (AN), Composition 4 (C4), trinitrotoluene (TNT) and double base smokeless powder (SP). In Experiment 1, canines completed a 3-alternative forced choice 3-down-1-up staircase threshold assessment in five environmental conditions: 40°C and 70% relative humidity (RH), 40°C and 40% RH, 0°C and 90% RH, 0°C and 50% RH and 21°C and 50% RH. Canines showed a 3.5-fold detection limit increase (poorer detection) for C4 in 40°C and 70% RH compared to their detection limit at 21°C and 50% RH. In Experiment 2, the eight canines were split into two groups (n = 4), control and acclimation groups. The control group completed the threshold assessment for C4 at 21°C and 50% RH each day for 20 days, with 5 minutes of petting prior to testing. The acclimation group completed the same assessment daily starting at 21°C and 50% RH but temperature and RH were incremented daily over the course of 6 days to the 40°C and 70% RH condition. After the initial six days, the acclimation group completed daily assessments at 40°C and 70% RH condition for the remainder of the experiment. All acclimatization group canines started their session with 5 minutes of toy or food retrieves. Detection limits for C4 for all dogs were tested in 40°C and 70% RH on day 11 and day 22. The acclimatization plan improved detection limits in the 40°C and 70% RH condition for C4 compared to the non-acclimated group. In this set of experiments, canine detection limits for four explosive odorants were found to vary based on environmental condition and were mostly driven by impacts on the canine rather than odor availability. The acclimatization plan did result in lower detection limits (i.e., increased performance). Future work should determine what factor (exercise or environmental exposure) is more effective in acclimatization for odor detection work.

Scientific and technical assistance on welfare aspects related to housing and health of cats and dogs in commercial breeding establishments

This Scientific Report addresses a mandate from the European Commission according to Article 31 of Regulation (EC) No 178/2002 on the welfare of cats and dogs in commercial breeding establishments kept for sport, hunting and companion purposes. The aim was to scrutinise recent recommendations made by the EU Platform on Animal Welfare Voluntary Initiative on measures to assist the preparation of policy options for the legal framework of commercial breeding of cats and dogs. Specifically, the main question addressed was if there is scientific evidence to support the measures for protection of cats and dogs in commercial breeding related to housing, health considerations and painful procedures. Three judgements were carried out based on scientific literature reviews and, where possible a review of national regulations. The first judgement addressed housing and included: type of accommodation, outdoor access, exercise, social behaviour, housing temperature and light requirements. The second judgement addressed health and included: age at first and last breeding, and breeding frequency. Judgement 3 addressed painful procedures (mutilations or convenience surgeries) and included: ear cropping, tail docking and vocal cord resections in dogs and declawing in cats. For each of these judgements, considerations were provided indicating where scientific literature is available to support recommendations on providing or avoiding specific housing, health or painful surgical interventions. Areas where evidence is lacking are indicated.

The Effect of Two Acute Bouts of Exercise on Oxidative Stress, Hematological, and Biochemical Parameters, and Rectal Temperature in Trained Canicross Dogs

Canicross is a sport discipline that connects human and canine athletes in running. Changes in physiological, hematological, and biochemical parameters, and exercise-induced oxidative stress have not been thoroughly characterized in canicross dogs. The aim of our study was the assessment of the health status of trained canicross dogs that were subjected to two acute bouts of exercise with their owners during the training season. Health status was assessed by measuring the rectal temperature, hematological and biochemical parameters, as well as blood oxidative stress parameters (plasma malondialdehyde, lipid peroxidation marker; whole blood glutathione peroxidase and erythrocyte superoxide dismutase1, antioxidant enzymes) before and during a two-day canicross training session and after a 24-h rest period. Seven trained canicross dogs (three females/four males) aged 12–120 months were included in the study. Blood samples were collected before and immediately after the first acute bout of exercise (day 1), after the second acute bout of exercise (day 2), and after 24 h of rest (day 3). Rectal temperature was measured at the same time as blood sample collection. The majority of hematological and biochemical parameters remained within reference ranges at all sampling times. Rectal temperature was significantly higher after training on days 1 and 2 compared to resting temperature on day 3. Hematological parameters did not change significantly; however, there were significant differences in urea, creatinine, creatine kinase, and triglycerides between specific sampling times. Despite significant changes, these biochemical parameters remained within reference ranges. Significant changes in biochemical parameters seem to reflect the dogs' physiological response to each acute bout of exercise, considering all biochemical parameters and rectal temperature returned to pre-exercise values after a 24-h rest period (day 3). No significant differences in oxidative stress parameters were found between any sampling times. Relatively high erythrocyte superoxide dismutase1 activity at all sampling times may indicate that the canicross dogs are adapted to training by an increased expression of antioxidant enzymes. Based on our results, we can conclude that the trained canicross dogs included in our study were healthy, in good physical condition, and fit for the two acute bouts of field exercise.

Exploring Owner Perceptions of the Impacts of Seasonal Weather Variations on Canine Activity and Potential Consequences for Human-Canine Relationships

Simple Summary

Dog walking is important for maintaining the good health and welfare of pet dogs. Environmental factors such as weather conditions have been previously identified as potential barriers to dog walking but, so far, focus has been on the impact this has on the human. With more seasonal weather variation predicted due to climate change, it is unclear if weather also impacts on the willingness of dogs to undertake exercise and thus the overall activity levels of pet dogs. An online survey recruited 3153 respondents to outline the impact of summer and winter weather conditions on daily canine activity levels. Owners reported their dogs were more impacted by cold (48.2% less likely to exercise their dog in the cold) and ice (64.0% less likely), than rain (25.3% less likely). In hot weather, 81.7% of owners reported reduced exercise duration and 87.0% reported less vigorous exercise by their dogs. As extreme weather events are likely to become more commonplace, it is likely this will negatively impact dog activity levels. Climate change mitigation strategies must therefore include considerations for dogs, if our canine companions are to retain their positions of service and companionship.

Abstract

Climate change is leading to more instances of seasonal weather variation. Studies have explored the impact of adverse winter weather on dog walking, but the impact on the dog’s overall activity levels have not been previously considered. This study explored dog owner perceptions of the effects of both summer and winter weather on their dog’s activity levels. An international online survey recruited 3153 respondents between May and December 2018, to explore the impact of summer and winter weather conditions on baseline activity levels. Owners reported their dogs were more impacted by cold (48.2% less likely to exercise their dog in the cold) and ice (64.0% less likely), than rain (25.3% were less likely). In hot weather, over 80% of owners reported reduced exercise duration and vigour for their dogs. Carrying water or walking near water to facilitate activity in the summer was the most popular mitigation strategy (90.8%). Participation in dog sports appeared to reduce the impact of winter weather on canine activity and increase owner awareness of cooling strategies to facilitate summer activity. Strategies to promote safe activity participation are needed to maintain canine activity levels amidst rising global temperatures, including better understanding of cooling strategies for exercising dogs.

Comparison of body temperature in donkeys using rectal digital, infrared, and mercury-in-glass thermometers during the hot-dry season in a tropical savannah

The study aimed at comparing variations in body temperature values recorded using rectal digital, infrared, and mercury-in-glass thermometers in donkeys during the hot-dry season, prevailing under tropical savannah conditions. Thirty donkeys that served as subjects were divided into three groups of adults, yearlings, and foals. Values of the body temperature of each donkey were recorded bihourly, starting from 06:00 h till 18:00 h, by digital (5-cm depth of insertion), mercury-in-glass (3 cm depth), and infrared thermometers. The values obtained by each type of the thermometer were compared with those recorded using a 15-cm digital probe (Model HI935007, Hanna Instruments, range -50.0 to 150.0°C; accuracy ± 0.2°C) which served as the gold standard. Dry-bulb temperature (34.00 ± 0.50°C), temperature-humidity index (79.65 ± 0.15), and wet-bulb globe temperature (28.00 ± 0.50) index peaked at 14:00 h. The mean body temperatures for rectal probe, digital, mercury-in-glass, and infrared thermometers were 38.35 ± 0.11°C, 37.24 ± 0.04°C, 36.76 ± 0.06°C, and 36.92 ± 0.07°C, respectively. In comparison to the rectal probe, the mean bias for digital (-1.11 ± 0.05°C), mercury-in-glass (-1.59 ± 0.07°C), and infrared thermometers (-1.38 ± 0.07°C) was large. The Passing-Bablok regression plot demonstrated significant deviation from linearity (p < 0.01) when digital, infrared, and mercury-in-glass thermometers were compared to the rectal probe. The area under the curve (AUC) for digital (AUC: 0.7005 ± 0.01 [95%: 0.6853 - 0.7310], infrared (AUC: 0.6711 ± 0.01 [95%: 0.6322 - 0.7100], and mercury-in-glass (AUC: 0.6321 ± 0.01 [95%: 0.6001 - 0.7873] thermometers showed poor accuracy with low sensitivity. In conclusion, the use of digital, mercury-in-glass, and infrared thermometers in recording body temperature in donkeys during the hot-dry season underestimated the values. Their use in measuring body temperature may result in wrong diagnosis, and compromise the control of hyperthermia and diseases associated with thermoregulatory impairments in donkeys.

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.

Demographic Changes in UK Rescue Centre Dog Population between 2014 and 2018

Rescue centers remain a common means of rehoming a dog. There is a paucity of research into the composition of rescue center populations and its potential reflection of increased popularity of brachycephalic breeds. The study investigated changes in rescue center demographics from 2015 to 2018, compared to the wider dog population. Dogs on 16 rehoming centers' websites were recorded weekly from June 2015 for 8 weeks and replicated from June 2018. Data were collected on 1793 dogs across the centers. Over 50% of which were classified as purebred in both years. Over 80% of the dogs were categorized into 24 breeds or breed crosses. Dogs categorized as brachycephalic increased from 24 (2.76%) in 2015 to 48 (5.19%) in 2018. Subadult dogs (3-4 years) were most prevalent in both years. While sex, breed type, and age of the rehoming center population has remained relatively stable, breeds are changing. Whilst low, brachycephalic numbers doubled in 3 years, mirroring their rising popularity within the UK, impacting on rehoming centers and prospective new owners with additional costs of brachycephalic obstructive airway syndrome surgery.

Dogs Don't Die Just in Hot Cars-Exertional Heat-Related Illness (Heatstroke) Is a Greater Threat to UK Dogs

Heat-related illness will affect increasing numbers of dogs as global temperatures rise unless effective mitigation strategies are implemented. This study aimed to identify the key triggers of heat-related illness in dogs and investigate canine risk factors for the most common triggers in UK dogs. Using the VetCompassTM programme, de-identified electronic patient records of 905,543 dogs under primary veterinary care in 2016 were reviewed to identify 1259 heat-related illness events from 1222 dogs. Exertional heat-related illness was the predominant trigger (74.2% of events), followed by environmental (12.9%) and vehicular confinement (5.2%). Canine and human risk factors appear similar; young male dogs had greater odds of exertional heat-related illness, older dogs and dogs with respiratory compromise had the greatest odds of environmental heat-related illness. Brachycephalic dogs had greater odds of all three types of heat-related illness compared with mesocephalic dogs. The odds of death following vehicular heat-related illness (OR 1.47, p = 0.492) was similar to that of exertional heat-related illness. In the UK, exertional heat-related illness affects more dogs, and kills more dogs, than confinement in a hot vehicle. Campaigns to raise public awareness about heat-related illness in dogs need to highlight that dogs don't die just in hot cars.

Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 2016

As climate change causes global temperatures to rise, heat-related illness, a potentially fatal condition in dogs, will become an ever-greater threat. This study aimed to report the incidence, fatality and canine risk factors of heat-related illness in UK dogs under primary veterinary care in 2016. The VetCompass^TM programme collects de-identified electronic patient records from UK veterinary practices for research. From the clinical records of 905,543 dogs under veterinary care in 2016, 395 confirmed heat-related illness events were identified. The estimated 2016 incidence of heat-related illness was 0.04% (95% CI 0.04-0.05%), with an event fatality rate of 14.18% (95% CI 11.08 – 17.96%). Multivariable analysis identified significant risk factors including breed (e.g. Chow Chow, Bulldog and French Bulldog), higher bodyweight relative to the breed/sex mean and being over two years of age. Dogs with a brachycephalic skull shape and dogs weighing over 50 kg were also at greater risk. As we move into an ever-warmer world, veterinary professionals may need to include resistance to heat-related illness amongst their rationales when advising owners on breed selection. Breeding for good respiratory function and maintaining a healthy bodyweight should be considered key welfare priorities for all dogs to limit the risk of heat-related illness.

Changes in Pulse Rate, Respiratory Rate and Rectal Temperature in Working Dogs before and after Three Different Field Trials

Simple Summary

Competitions dedicated to working dogs have greatly expanded in order to select the best canine individuals for Search-and-Rescue (SAR) activity. Therefore, it is essential to identify physiological parameters for a rapid clinical evaluation in order to provide useful information on the physical fitness of athlete dogs. In the present study, heart rate, respiratory rate and rectal temperature were investigated during three different working activities. Heart rate was the most conditioned parameter by exercise and, probably, the most useful to evaluate the canine predisposition and response to work. Respiratory rate and rectal temperature were more affected by environmental variables.

Abstract

Physiological changes (pulse rate, respiratory rate and rectal temperature) induced by exercise are usually studied as physical fitness indices. The aim of this study was to investigate how these physiological parameters could be modified in a group of trained working dogs during three different field trials (rubble, search on field, obedience), in order to assess which parameter would be more useful to detect the dog response to exercise. Nine dogs were included in this study. The animals were monitored at rest, immediately before and after the working session. Pulse rate values increased significantly in all the phases compared to rest status. Respiratory rate values increased significantly after the competition, while rectal temperature was significantly increased only after search on rubbles and obedience activities. Reference values for specific competitions need to be stablished in order to promptly identify poor performance or exercise intolerance.

Comparing alternatives to canine rectal thermometry at the axillary, auricular and ocular locations

Body temperature is an important component in the diagnosis and treatment of disease in canines. The rectal temperature remains the standard of obtaining temperature within the clinical setting, but there are many drawbacks with this method, including time, access, animal stress, and safety concerns. Interest in using infrared thermometry in canines to obtain body temperature has grown as animal scientists and veterinarians search for non-invasive and non-contact methods and locations of obtaining canine temperatures. Here, we review evidence on axillary, auricular, and ocular region canine thermometry and the degree to which measurements in these locations are representative of rectal temperature values. Instrumentation refinement and development, as well as morphologic differences, play an important role in the potential correlation between the rectal temperature and these other locations. These caveats have yet to be fully addressed in the literature, limiting the options for those seeking alternatives to rectal thermometry.

Risk factors for exertional heat illness in Thoroughbred racehorses in flat races in Japan (2005-2016)

BACKGROUND

Exertional heat illness (EHI) is recognised in horses, but few reports have investigated its risk factors.

OBJECTIVES

To identify risk factors for EHI in racehorses participating in flat races in Japan.

STUDY DESIGN

Descriptive epidemiology and retrospective unmatched case-control study.

METHODS

Between 2005 and 2016, veterinary records of horses diagnosed with EHI after flat races were reviewed retrospectively and data of the months from April to September were used for a case-control study. For each case, three control horses were randomly selected from starts between April and September. Race records of horses and estimated wet-bulb globe temperature (WBGT) indexes at the local meteorological observatory closest to the racecourse were investigated. To identify risk factors for EHI, univariable and multivariable logistic regression analysis was used.

RESULTS

Of 194 cases during the study period, 188 cases occurred between April and September. The highest incidence risk was in July (1.1 cases per 1000 starts, 95% confidence interval 0.84-1.45). In the final multivariable model, WBGT index, sex, race distance, age and bodyweight were associated with EHI. When WBGT index exceeded 28°C, the risk of EHI was considerably higher than <20°C (OR 28.5, 14.2-62.4, P<0.001). Compared with uncastrated males, geldings (OR 4.9, 1.8-13.3, p = 0.002) and females (OR 2.4, 1.5-3.7, P<0.001) were at high risk of EHI (P<0.01). Furthermore, races of >1600 m (OR 1.8, 1.2-2.8, P = 0.002), 4-year-old (OR 3.5, 1.6-7.9, P = 0.002) and ≥5-year-old (OR 3.9, 1.8-9.2, P = 0.001) horses and horses with low bodyweight (OR per 20 kg, 0.8, 0.7-1.0, P = 0.02) were associated with increased risk of EHI.

MAIN LIMITATIONS

The median straight-line distance between the racecourse and the local meteorological observatory was 14.2 km (range, 1.1-28.3 km). There was a lack of objective criteria of EHI due to the retrospective nature of the study.

CONCLUSIONS

We identified specific risk factors for EHI in racehorses. These results may be useful to the equine industry for reducing EHI occurrence in racehorses.

Evaluation of the effect of urine dip vs urine drip on multi-test strip results

Standard operating procedures, including World Health Organization guidelines for packed cell volume, are established for in-clinic laboratory tests. No independent, evidence-based guidelines exist for dipstick urinalysis; however, manufacturer's instructions state to dip the stick into urine. In veterinary medicine, small volume urine samples could preclude dipping; therefore, a single drip per pad from a pipette or syringe is often performed. This study aimed to examine the differences between these two urine application methods prior to analysis, with the hypothesis that the method type would not effect on test results of dipstick analysis. To standardize the strip analysis method, a Siemens Clinitek Status + analyzer was used with Multistix10SG dipsticks. Three investigators tested urines from 53 dogs with a range of diseases by both methods. Results were assessed for the degree of agreement between the methods and within method variability. Overall, the agreement between methods was high. Within each method, the drip method variability was higher than that of the dip method (P = 0.012). Disagreements between methods were present, with pH and blood having the lowest agreement levels. Glucose was more likely to be positive on the drip compared with the dip methodology. This study demonstrates potential clinically relevant differences between the two methods and a higher level of variability with the drip methodology. Therefore, while the drip method could be used for practical reasons (eg, low sample volumes), this study supports the manufacturer's recommended method of dipping the dip stick into urine rather than dripping urine onto each pad with a pipette or syringe.

Quantifying body surface temperature differences in canine coat types using infrared thermography

Infrared thermography (IRT) has been used to assess the health of canines by measuring surface temperatures. However, little is known about the effect hair coat differences has on expected surface temperature in healthy canines under the influence of hair coat differences. The aim of this study was to identify the influence of coat characteristics in body surface temperature (BST) in canines (Canis lupus familiaris). To determine the changes in BST, an infrared thermal imaging camera (i.e. FLIR B400) was used. Thermal images of the left and right sides of privately-owned dogs (n = 50) were acquired. Each animal acclimated in an indoor environment away from direct sunlight (23 ± 2.0 °C) for 15 min, and images were taken at a distance 0.67 ± 0.24 m. Regions of interest (ROIs) of mean surface temperatures were examined across the lateral surface of each animal. No statistical differences were detected based on laterality (P = 0.08). Mean BSTs were categorized by each dog's hair coat type: short coat (SC), curly coat (CC), long coat (LC), and double coat (DC). These BSTs were then analyzed using two-way analysis of variance, or ANOVA, (Shapiro-Wilk) and pairwise comparison. SC animals had the highest BST (31.77 ± 0.19 °C; P < 0.001) whereas LC (28.14 ± 0.31 °C; P < 0.001) and DC animals (28.25 ± 0.23 °C; P < 0.001) were lower in BST. CC animals portrayed intermediate BST (29.85 ± 0.33 °C; P < 0.001). The Pearson correlation and one-way ANOVA between rectal temperature and BST and coat type were not statistically significant (r = -0.24 and P = 0.07, respectively). Results indicate that short-haired dogs exhibit a more drastic increase in BST (approximately 2 °C) in comparison to other dogs and this should be considered in future clinical applications.

Predicting recovery from exertional heat strain in military working dogs

A two-compartment (core, skin) rational Canine Thermal Model (CTM) of thermal-physiological responses was developed to predict the core temperature (Tc) of a military working dog (MWD) during recovery from exertional heat stress. Heat storage is represented as the balance among heat loss mechanisms, heat gain from the environment, and heat production from metabolism. Inputs to the CTM include environmental conditions (ambient temperature, relative humidity, solar radiation and wind speed), physical characteristics of the dog (weight, length), and metabolic rate. The CTM was validated against Tc of 16 MWDs measured in a previous study, where training was conducted in October (24 °C, 52% RH), March (14 °C, 74% RH), and August (28 °C, 64% RH). Measured and CTM-simulated Tc were compared at 5, 10, 15, 30 and 60 min post-exercise. The CTM was considered acceptable if it was within 0.5 °C of measured Tc for 80% of cases. This occurred in 92% of 37 cases after 30 min recovery, and 86% of 29 cases after 60 min. The mean difference between CTM-simulated and measured Tc was - 0.01 °C at 30 min recovery, with 2 of 37 cases falling outside the range of two standard deviations (Bland Altman comparison). After 60 min recovery the difference was 0.05 °C, with 4 of 29 cases outside the range of acceptance. The root mean squared deviation between CTM-simulated and measured Tc for all time points was 0.3 °C ± 0.3 °C. For comparison, the mean ± standard deviation of resting Tc was 38.2 °C ± 0.3 °C and at peak Tc was 39.4 °C ± 0.7 °C. For this population, the CTM is a valid method for simulating recovery from exertional heat stress. It can be used to develop work / rest cycles during activity in hot environments, and to compare rates of recovery across different environmental conditions.

Physiological parameter values in greyhounds before and after high-intensity exercise

Dog sports competitions have greatly expanded. The availability of reference values for each type of activity could help assess fitness accurately. Heart rate (HR), blood lactate (BL) and rectal temperature (RT) are relevant physiological parameters to determine the dogs response to effort. Previous studies in greyhounds have reported the effect of high-intensity exercise on many physiological parameters immediately after completing different racing distances and recovery times. However, there are no studies concerning physiological changes over shorter racing distances. We therefore assessed the effect of sprint exercise on HR, BL and RT in nine greyhounds performing sprint exercise over a 100-m distance chasing a lure. After the exercise, dogs underwent a passive 10-min recovery phase. Before the exercise, immediately after it and at 5 and 10 min during recovery, HR and RT were assessed and blood samples were collected for BL determination. HR, BL and RT values increased significantly after the exercise (P<0.01). Whereas HR returned to pre-exercise values at 10 min during the recovery phase (P>0.1), BL concentration and RT remained increased (P<0.01). The abrupt increase in HR, BL and RT values observed immediately after the exercise indicates the high intensity of the effort performed. Similarly, BL concentration after the exercise exceeded the 4 mmol/L lactate threshold, suggesting a predominant anaerobic metabolism during effort. Although HR returned to pre-exercise values 10 min after the exercise, a more extensive recovery phase would be necessary for a total return to resting values, particularly for BL and RT. In greyhounds subjected to high-intensity exercise, HR, BL and RT were reliable physiological parameters to accurately assess the physiological response to effort. The use of sprint exercises over short racing distances could be useful for appropriately monitoring fitness in sporting dogs.

Investigating factors affecting the body temperature of dogs competing in cross country (canicross) races in the UK

Increasing numbers of people are running with their dogs, particularly in harness through the sport canicross. Whilst canicross races are typically held in the winter months, some human centred events are encouraging running with dogs in summer months, potentially putting dogs at risk of heat related injuries, including heatstroke. The aim of this project was to investigate the effects of ambient conditions and running speed on post-race temperature of canicross dogs in the UK, and investigate the potential risk of heatstroke to canicross racing dogs. The effects of canine characteristics (e.g. gender, coat colour) were explored in order to identify factors that could increase the risk of exercise-induced hyperthermia (defined as body temperature exceeding the upper normal limit of 38.8°C).108 dogs were recruited from 10 race days, where ambient conditions ranged from - 5 to 11°C measured as universal thermal comfort index (UTCI). 281 post race tympanic membrane temperatures were recorded, ranging from 37.0-42.5°C. There was a weak correlation between speed and post-race temperature (r = 0.269, P < 0.001). Whilst no correlation between any single environmental factor or UTCI and post-race temperature was found, the proportion of dogs developing exercise-induced hyperthermia during the race increased with UTCI (r = 0.688, P = 0.028). Male dogs (χ(1) = 18.286, P < 0.001), and dark coated dogs (χ(2) = 8.234, P = 0.014), were significantly more likely to finish the race with a temperature exceeding 40.6°C. Prolonged elevati°n of body temperature above this temperature is likely to cause heatstroke. At every race dogs exceeded this critical temperature, with 10.7% (n = 30) of the overall study population exceeding this temperature throughout the study period. The results suggest male dogs, dark coloured dogs, and increased speed of running all increase the risk of heatstroke in racing canicross dogs. Further research is required to investigate the impact of environmental conditions on post-race cooling, to better understand safe running conditions for dogs.