Environmental and Physiological Factors Associated With Stamina in Dogs Exercising in High Ambient Temperatures

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.

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.

First detection and genetic identification of Rickettsia spp. from ticks collected from rodents in north India

BACKGROUND

Changing climatic conditions and invasion of ticks in urban areas have led to a greater number of cases of tick-borne diseases, thus, becoming a matter of increasing concern. Tick borne rickettsioses are one of the important emerging diseases worldwide. Knowledge of epidemiology of the vector and pathogen in the community is essential in order to understand and prevent the transmission of the disease to healthy population.

METHODS

In our present study, we trapped rodents in selected areas of Chandigarh and Punjab in north India. The rodents were screened for the presence of ticks which were further screened for the presence of rickettsial agents. PCRs targeting 17 ​kDa and gltA genes were carried out followed by Sanger sequencing of the positive amplicons followed by phylogenetic analysis of the sequences.

RESULTS

A total of 17 ticks were collected out of which one (Rhipicephalus sanguineus) was found to be harboring a Rickettsia sp. PCR targeting gltA and 17 ​kDa genes of rickettsia were put up and Sanger sequencing was performed. Phylogenetic analysis revealed the sequences to be closely related to Rickettsia rhipicephali.

CONCLUSION

The current study establishes the presence of rickettsial agents in the community. Although Rickettsia rhipicephali is a non-pathogenic agent, the study encourages more vigorous community surveillance should be carried out in order to determine the exact burden of rickettsial agents in our community. To our knowledge, this is the first study reporting Rickettsia rhipicephali in India.

Physical activity and sport-specific training patterns in Swedish sporting and working trial dogs-A questionnaire survey

OBJECTIVE

To explore physical activity patterns, including conditioning exercise and sport-specific training, and management routines utilized by handlers of Swedish sporting and working dogs participating in agility, obedience, rally obedience and working trial disciplines.

PROCEDURES

Dog handlers provided information on competition-level dogs through an internet-based cross-sectional and descriptive survey on physical activity, sport-specific training and management. Results are reported overall and stratified by participation in specific disciplines.

RESULTS

We received 1615 replies to the questionnaire. After data cleaning, 1582 dogs (98%) remained for the analysis. Of these, 430 participated in agility, 790 in obedience, 596 in rally obedience, and 847 dogs had competed in a working trial, i.e., messenger, protection, search or tracking. Number of disciplines performed by each dog varied between one and five. Most common was participation in one (n = 767, 48%) or two (n = 541, 34%) disciplines. Out of the dogs competing in one discipline, 38% (n = 294) were considered to be specialized as they actively trained only that discipline for ≥10 months per year. The vast majority of the dogs (n = 1129, 71%) received more than 1 h of daily physical activity, e.g., walks, and only n = 51 (3%) were never exercised off-leash. Preferred self-selected gait was trot (n = 907, 57%) and gallop (n = 499, 32%). A fifth (n = 319, 20%) never played with other dogs. The majority (n = 1328, 84%) received more than 1 h of vigorous physical conditioning exercise per week. Almost three quarters (n = 1119, 71%) participated in physical conditioning exercise. Two thirds (n = 953, 60%) participated in at least 3 h of sport-specific training per week and only a very small portion (n = 35, 2%) trained their specific discipline less than once per week. Median total work load, i.e., all daily physical activity, vigorous physical conditioning exercise and sport-specific training, was 16.5 h per week.

CONCLUSION AND CLINICAL RELEVANCE

We observe physical activity at moderate to high durations and moderate to vigorous intensities among Swedish sporting and working trial dogs. Most dogs received physical conditioning exercise, but not all dogs were warmed up before training and competition. Our study provides veterinary professionals and dog trainers with valuable insights on the physical exposures and management routines of sporting and working trial dogs.

Clinical Evaluation of Exercise-Induced Physiological Changes in Military Working Dogs (MWDs) Resulting from the Use or Non-Use of Cooling Vests during Training in Moderately Hot Environments

Simple Summary

A cooling vest is a clothing article especially designed to reduce body temperature and make exposure to heat in hot climates or environments more bearable. Such cooling vests can be of significant help to military working dogs (MWDs) in high-temperature regions. Dogs performing scent-detection tasks could benefit from the use of a cooling vest, if proven useful, by reducing the risk of heat stroke and olfactory fatigue. As different models of cooling vests are available for dogs, our aim was to compare wearing nothing versus two different models of cooling vests in a homogenous dog population during physical exercise (moderate-intensity running). We observed that the evaporative cooling waistcoat performed best. In conclusion, the waistcoats improve the cooling of the dogs during and after exercise, and differences between the two garment models exist.

Abstract

Nose work with military working dogs (MWDs) in warmer-than-usual areas has led us to look for new tools to reduce both heat stress and the risk of heat stroke. One of the different strategies to manage heat stress is the use of cooling vests, such as those used in humans. The aim was to assess three cooling conditions (using two different cooling vests during exercise and the non-use of such garments) by measuring core body temperature, systemic blood pressure and pulse rate before and after the exercise (moment: four measurement times) in military dogs of the I Military Police Battalion (in Valencia, Spain). All dogs were evaluated under all three conditions during the three days of the study. Significant differences were observed between condition, moment, and the interaction of these two factors, in relation to core body temperature and pulse rate. Therefore, the use of an evaporative cooling vest may further be useful as a routine thermal control and conditioning measure in MWDs.

Dog Handler Beliefs regarding Barriers and Facilitators to Canine Health Promotion and Injury Prevention in Swedish Working Dog Trials and Competitions

Dog trials and competitions involve various sport disciplines, e.g., obedience, agility, working dog trials and rally obedience. Dog handlers navigate their dogs through physically and mentally demanding tasks. The purpose of this study was to gain a better understanding of barriers and facilitators to canine health promotion and injury prevention described by dog handlers.

METHODS

Qualitative inductive content analysis was applied to systematically organize and interpret narrative data from 654 respondents' answers to open-ended questions in an anonymous online inquiry.

RESULTS

Two categories, with seven sub-categories, emerged from the analysis: (1) Challenges in applying the regulations in dog trials and competitions, and (2) Implementation of animal welfare and canine well-being approaches. Respondents described the challenges in applying regulations in dog trials and competitions and lack of scientific research as barriers to their intent to prevent injuries in their dogs. Implementation of animal welfare and canine well-being approaches were described as facilitators.

CONCLUSION

The findings imply that the stakeholders continuously need to work on bridging possible gaps between the canine welfare criteria and the scientific and empirical knowledge in canine sports and performance medicine.

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.

Efficacy of high-intensity interval training compared with moderate-intensity continuous training on maximal aerobic potency in dogs: Trial protocol for a randomised controlled clinical study

BACKGROUND

High-intensity interval training (HIIT) is a more efficient method to improve exercise capacity than moderate-intensity continuous training (MICT) because of its greater physiological stimulus.

OBJECTIVE

The aim of this protocol is to evaluate the efficacy of HIIT on maximal aerobic potency in dogs as compared to MICT.

METHODS

This protocol is for a randomised, blinded controlled clinical trial, with three parallel groups for the purpose of demonstrating superiority. Thirty dogs aged between 12 and 84 months of both sexes and different breeds will be included. Dogs, before initiating and after finalising the training will perform an incremental exercise test on a treadmill to obtain maximal speed and lactate threshold; resting parameters of heart and respiratory rate, left ventricle chamber and systolic function will be measured. Dogs assigned to each intervention will endure a 42-min session of HIIT or MICT during 12 weeks. HIIT comprises four intervals of 4 min each at a load of 85%, alternating with a 4-min resting period. MICT group will have a continuous load of 60%. The control group will remain in a cage. An intention-to-treat statistical analysis will be implemented. Analysis of covariance will be used to estimate the effect of HIIT compared with MICT training on maximal aerobic potency, aerobic resistance, systolic function at rest, left ventricle chamber measurements and indexes, respiratory rate and HR at rest.

CONCLUSION

Significant time and effort are invested into training sports/working dogs, which could benefit from improving physical capacity by means of the HIIT methodology.

2021 AAHA Working, Assistance, and Therapy Dog Guidelines

The guidelines are the first comprehensive consensus report on veterinary healthcare recommendations for working, assistance, and therapy dogs. This category of canine patients includes a broad assortment of animals, some with well-defined functions and others that provide a more generalized support role. The guidelines discuss recommendations for dogs trained for protection, odor/scent detection, service functions for people with diagnosed disabilities or physical limitations, emotional support, and therapeutic intervention. Although the term is often used to describe dogs providing animal-assisted activities, true therapy dogs provide goal-directed therapy, often under the supervision of a healthcare professional such as an occupational therapist or psychologist. Many working dogs undergo extensive training and have rigorous physical demands placed upon them. These factors make working, assistance, and therapy dogs inherently valuable and impose a need for a high level of primary veterinary care as described in the guidelines. Because working dogs have a particularly close relationship with their handlers, a trust relationship between the practice team and the working-dog client is imperative.

Thermal Imaging Following Exercise in Working Dogs

Disaster search dogs traverse diverse and unstable surfaces found in collapsed buildings. It is unknown if the physical conditioning on a treadmill involves the same muscle groups that are involved in rubble search. This 14-week prospective cohort study was conducted to investigate changes within the thermal gradients of specific dog muscles following treadmill compared to rubble search. Nine dogs, ranging in age from 6 months to 4 years, were randomly assigned to one of two groups. Each week the two groups would participate in either 20 min of treadmill or rubble searches. Prior to exercise, the dogs were weighed and then kenneled in a temperature-controlled study room for 20 min at 21°C. Pre-exercise thermal images were then captured of the standing dog from the dorsal, left and right lateral, and caudal perspectives, and of the sitting dog from the rostral perspective. Following a 10-min warm-up period of stretches, dogs proceeded to either treadmill or search. Upon completion, dogs were kenneled in the study room for 20 min prior to post-exercise thermal images. Images were sectioned into 22 muscle regions, the pre-exercise images were subtracted from the post-exercise images to determine the temperature difference (ΔT) for that dog, on that day, for that activity. Thermography measures radiant energy, temperature, and converts this information into an image. This study looked at ΔT within a region pre and post-exercise. The study failed to find a statistically significant difference in the ΔT within each muscle group between treadmill and search activities. There was a decrease in ΔT within all muscle regions over the of the study except for the right cranial shoulder, right caudal shoulder, and right hamstring for the treadmill activity only. The decrease was significant in the pelvis, left longissimus, right cranial shoulder for the search activity, left oblique, left caudal shoulder, and left quadricep muscular regions. These findings suggest that ΔT in muscle groups are similar between treadmill exercise and rubble search. Regardless of the exercise type, 14 weeks of structured Search and Rescue training and treadmill exercise resulted in less ΔT associated with a structured weekly exercise.

Nutrition of Working Dogs: Feeding for Optimal Performance and Health

Working dogs are athletes, but have a wide variety of work types and durations that impact their dietary needs. Their basic nutritional needs do not change: all dogs need a complete and balanced diet, fed in proper proportions to maintain optimal body condition. However, with increasing muscle work and endurance, the amounts of specific nutrients (particularly the macronutrients, protein, fat, and carbohydrates) must be adjusted. This article provides an overview of the key aspects of working canine nutrition and provides the nutritional science behind the recommendations made.

Canine Special Senses: Considerations in Olfaction, Vision, and Audition

Canine companions have learned to aid in performing tasks and conducting work for decades. Areas where unique capabilities of working dogs are harnessed are growing. This expansion, alongside efforts to increase domestic purpose-bred stock and awareness of the important role working dogs play in society, is increasing the role veterinarians provide. This article provides a brief overview of 3 key sensory systems in working dogs and highlights considerations for care related to each olfaction, audition, and vision.

Operational Canine

Operational K9s encompass a unique population of working dogs that serve as a force multiplier in various civilian law enforcement, force protection, search and rescue, and humanitarian operations. These elite canines do not volunteer to serve, yet they are some of the most faithful and dependable operators in the field. They undoubtedly perform an invaluable service in today's society and are owed a tremendous debt of gratitude for their selfless service, loyalty, and sacrifices. This article describes the unique characteristics and occupational hazards that pertain to the community of Operational K9s.

Supplemental Fiber Affects Body Temperature and Fecal Metabolites but Not Respiratory Rate or Body Composition in Mid-Distance Training Sled Dogs

Dietary fiber affects canine physiology in many ways, such as increasing colonic absorption of water and improving gut health, both of which may positively impact exercise performance. The objectives of this study were to investigate the effects of increased dietary soluble fiber and incremental training on respiratory rate (RR), internal body temperature (BT), body composition, and fecal metabolites in mid-distance training sled dogs. Fourteen dogs (12 Siberian and 2 Alaskan Huskies) were blocked by age, sex, and body weight (BW) and then randomly allocated into one of two diet groups. Seven dogs were fed a dry extruded control diet (Ctl) with an insoluble:soluble fiber ratio of 4:1 (0.74% soluble fiber on a dry-matter basis), and seven dogs were fed a dry extruded treatment diet (Trt) with an insoluble:soluble fiber ratio of 3:1 (2.12% soluble fiber on a dry-matter basis). Fecal samples were taken once a week. All dogs underwent 9 weeks of incremental exercise conditioning where the running distance was designed to increase each week. Every 3 weeks, external telemetry equipment was used to non-invasively measure and record RR and internal BT at resting, working, and post-exercise recovery states. Body composition was measured on weeks −1 and 9 using quantitative magnetic resonance. Body composition, RR, BT, and fecal metabolites were analyzed using a mixed model with dog as a random effect and week and diet group as fixed effects. Dogs on Trt had lower working and post-exercise BT than Ctl (P < 0.05). In addition, Trt dogs had lower recovery BT at weeks 2 and 5 than Ctl dogs (P < 0.05). Treatment dogs had greater fecal short-chain fatty acid concentrations than Ctl (P < 0.05). Diet had no effect on RR or body composition (P > 0.10), but exercise resulted in an overall 7% increase in lean and 3.5% decrease in fat mass (P < 0.05). These data suggest that increasing dietary soluble fiber may positively influence BT and gut health; however, it has no effect on RR or body composition. Soluble fiber did not negatively impact any measures of overall health and performance and should be considered for use in performance dogs.

Proposing the VetCompass clinical grading tool for heat-related illness in dogs

Heat-related illness is a potentially fatal condition in dogs. Rapid and accurate recognition of the severity can improve clinical management in affected dogs and lead to better outcomes. This study explored retrospective VetCompass veterinary clinical records to investigate the clinical signs recorded for dogs presenting with heat-related illness to primary-care veterinary practice from 2016 to 2018. The relative risk of death associated with these clinical signs was reported and used to develop a novel clinical grading tool. From the clinical records of 856 heat-related illness events, the most frequently recorded clinical signs were respiratory changes (68.73%) and lethargy (47.79%). The clinical signs with the highest relative risk of death were neurological dysfunction, gastrointestinal haemorrhage and bleeding disorders. The novel VetCompass Clinical Grading Tool for Heat-Related Illness in dogs defines three grades: mild (altered respiration, lethargy), moderate (gastrointestinal signs, a single seizure, episodic collapse) and severe (neurological dysfunction, gastrointestinal haemorrhage, bleeding disorders). This novel grading tool offers a simple, evidence-based device to improve recognition of heat-related illness in dogs and promote improved decision-making for earlier interventions such as cooling and hospitalisation. This could improve outcomes and protect the welfare of dogs in the face of rising global temperatures.

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.

Impact of High Temperature on Post-Exercise Albuminuria in Dogs

Simple Summary

The literature suggests that strenuous exercise and exposure to high temperatures may cause physiologic proteinuria, but there are no available data showing the effect of high temperature on the occurrence of post-exercise albuminuria in dogs. The goal of the present study was to assess impact of high temperature on the occurrence of albuminuria. A period of about 30–40 min of intensive exercise at high temperatures did not lead to increased albuminuria. This suggests that there is no need to limit physical activity before urine tests in dogs, even at high temperatures, before a urinalysis.

Abstract

The literature suggests that strenuous exercise and exposure to high temperatures may cause physiologic proteinuria, but to our knowledge there have been no studies that have assessed the effect of high temperatures on the occurrence of post-exercise albuminuria in dogs. The goal of the study was to assess the impact of high temperatures on the occurrence of albuminuria. Thirteen healthy adult dogs—eight female (62%) and five male (38%) had to run 5 km at a temperature of 25 °C in grasslands which took about 30–40 min. Dogs underwent clinical examinations: echocardiography, abdominal ultrasound, blood hematology and biochemistry and urinalysis, including the ratio of albumin to creatinine (UAC). Baseline UAC was on the borderline of statistical significance for female dogs, but not for male dogs, before and after exercise. UAC was 0.31 ± 0.56 mg/mmol for female dogs and 0.36 ± 0.60 mg/mmol in male dogs before exercise. Immediately after exercise, UAC was 0.51 ± 0.58 mg/mmol in female dogs and 0.31 ± 0.40 mg/mmol in male dogs. Thus, a period of about 30–40 min of intensive exercise at high temperatures (25 °C) did not lead to increased albuminuria. This suggests that there is no need to limit the movement activity before urine tests in dogs, even at high temperatures, before urinalysis.

A canine thermal model for simulating temperature responses of military working dogs

Military working dogs (MWDs) are often required to operate in dangerous or extreme environments, to include hot and humid climate conditions. These scenarios can put MWD at significant risk of heat injury. To address this concern, a two-compartment (core, skin) rational thermophysiological model was developed to predict the temperature of a MWD during rest, exercise, and recovery. The Canine Thermal Model (CTM) uses inputs of MWD mass and length to determine a basal metabolic rate and body surface area. These calculations are used along with time series inputs of environmental conditions (air temperature, relative humidity, solar radiation and wind velocity) and level of metabolic intensity (MET) to predict MWD thermoregulatory responses. Default initial values of core and skin temperatures are set at neutral values representative of an average MWD; however, these can be adjusted to match known or expected individual temperatures. The rational principles of the CTM describe the heat exchange from the metabolic energy of the core compartment to the skin compartment by passive conduction as well as the application of an active control for skin blood flow and to tongue and lingual tissues. The CTM also mathematically describes heat loss directly to the environment via respiration, including panting. Thermal insulation properties of MWD fur are also used to influence heat loss from skin and gain from the environment. This paper describes the CTM in detail, outlining the equations used to calculate avenues of heat transfer (convective, conductive, radiative and evaporative), overall heat storage, and predicted responses of the MWD. Additionally, this paper outlines examples of how the CTM can be used to predict recovery from exertional heat strain, plan work/rest cycles, and estimate work duration to avoid overheating.

Exercise but Not Supplemental Dietary Tryptophan Influences Heart Rate and Respiratory Rate in Sled Dogs

Tryptophan (Trp), an indispensable amino acid for dogs, is the precursor of serotonin, a neurotransmitter with a variety of effects throughout the body, including the ability to modulate cardiac and pulmonary activity. This study aimed to investigate the effects of a 12-week incremental exercise regimen and supplemental dietary Trp on heart rate (HR) and respiratory rate (RR) in client-owned sled dogs. Sixteen Siberian huskies were randomly allocated to either treatment or control diet groups. Both groups were fed a control diet (Trp to large neutral amino acid ratio of 0.047:1); however, treatment dogs received a Trp supplement to achieve a Trp to large neutral amino acid ratio of 0.075:1. Every three weeks, external telemetry equipment was used to non-invasively measure and record HR and RR at a resting, working, and post-exercise state in a controlled exercise challenge. A mixed model was used to test differences between diet, activity parameter, and week. Dietary Trp supplementation had no effect on HR or RR. Independent of diet, resting, working, post-exercise HR, and time to recover post-exercise HR decreased from week −1 to week 11 (p < 0.05). Resting HR had the greatest reduction from week −1 to week 11 (21%, p < 0.05). Working RR did not change with exercise (p > 0.10), but rRR and postRR decreased from week −1 to week 11 (p < 0.05). These data suggest that the exercise regimen the dogs were subjected to may have positively impacted the dogs’ capacity to sustain aerobic exercise, whereas Trp supplementation had no effect on HR or RR.

A Randomized Cross-Over Field Study of Pre-Hydration Strategies in Dogs Tracking in Hot Environments

The objective of this study was to evaluate 4 pre-exercise hydration strategies (oral water, chicken-flavored water, chicken-flavored oral electrolyte solution, and subcutaneous electrolyte solution) in working dogs conducting rigorous tracking operations in hot and arid conditions. In a randomized cross-over field study, 7 Border Patrol Search, Trauma, and Rescue (BORSTAR) Unit dogs working/training out of Fort Bliss in El Paso, Texas were randomly assigned to one of 4 different hydration strategy treatments each day for 4 days of study participation. Dogs were provided hydration treatment prior to running 2 separate one-mile tracks and were offered water while tracking. Body weight, blood, and urine were collected at the beginning of the study day and at the completion of each track. Core body temperatures were recorded using internal temperature sensing capsules. The impact of hydration strategy on change in weight, peak temperature, and serum chemical, hematological, and urinary parameters were analyzed using the COIN procedure in R^a. Compared to the other 3 hydration strategies, dogs receiving chicken-flavored water had higher blood creatine kinase values at the end of the second track (p = 0.0361). Otherwise, hydration strategy had minimal effects on blood or urine parameters. Total fluid intake was lower with water only compared to the other three hydration strategies. Dogs developed elevated core body temperatures (median 41°C; 106°F) without signs of heat exhaustion or heat stroke. Alternate hydration strategies increased total fluid intake compared to water alone; however, chicken-flavored water resulted in increased markers of muscle injury suggesting electrolyte-enriched strategies may have an advantage as a hydration strategy. Additionally, electrolyte-enriched fluids before exercise may help these dogs maintain lower peak temperatures.

Predicting military working dog core temperature during exertional heat strain: Validation of a Canine Thermal Model

Military working dogs (MWDs) operate under a wide range of conditions, including hot environments. Predicting how long a MWD can safely work without overheating is important for both health and performance. A Canine Thermal Model (CTM) was developed to predict core temperature (Tc) of MWDs. The CTM calculates heat storage from the balance of heat production from metabolism and heat exchange with the environment. Inputs to the CTM are: meteorological conditions (ambient temperature, relative humidity, solar radiation and wind speed), physical characteristics of the dog (mass, length), and metabolic activity (MET level, estimated from accelerometer data). The CTM was validated against Tc measured in 23 MWDs during training sessions (11.6 ± 5.0 min (mean ± standard deviation), range 4-26 min) in October (24 °C, 52% RH), March (14 °C, 74% RH), or August (28 °C, 64% RH), and 24 kennel MWDs during a standard exercise walk (11.4 ± 3.3 min, range 5.6-18 min) in July (26 °C, 77% RH). The CTM was considered acceptable if predicted Tc was within ±0.5 °C of measured Tc at the end of exercise. Compared to Tc at the end of training sessions (39.8 ± 0.6 °C, range 38.4-41.1 °C) and exercise walks (40.0 ± 0.7 °C, range 38.9-41.4 °C), the CTM-predicted Tc was within ±0.5 °C for 71 of 84 cases (85%) and 19 of 24 cases (79%), respectively. The mean difference between CTM-predicted and measured final Tc during training was -0.04 ± 0.43 °C, with 80 of 84 cases (95%) within the range of ±2 SD (Bland Altman comparison). During exercise walks the mean difference was -0.15 °C ± 0.57, with 23 of 24 cases (96%) within ±2 SD. These results support the use of the CTM to predict Tc of MWDs for the types of physical activities described above.

Changes in salivary electrolyte concentrations in mid-distance trained sled dogs during 12 weeks of incremental conditioning

Regular exercise improves the health status of dogs; however, extreme exertion in the absence of adequate fluid and electrolyte replacement may negatively impact health and performance due to dehydration and cardiovascular stress. Unlike humans and horses, dogs thermoregulate predominantly through respiration and salivation, yet there is a dearth of literature defining exercise-induced changes to canine salivary electrolytes. The study objective was to investigate the effects of exercise on salivary electrolyte concentrations, and to determine if adaptations may occur in response to incremental conditioning in client-owned Siberian Huskies. Sixteen dogs were used, with an average age of 4.8 ± 2.5 years and body weight of 24.3 ± 4.3 kg. A 12-week exercise regimen was designed to increase in distance each week, but weather played a role in setting the daily distance. Saliva samples were collected at weeks 0 (pre-run, 5.7 km), 5 (pre-run, 5.7, 39.0 km), and 11 (pre-run, 5.7, 39.0 km). Samples were analyzed for sodium, chloride, potassium, calcium, magnesium, and phosphorous using photometric and indirect ion-selective electrode analysis. When compared across weeks, sodium, chloride, potassium, and calcium concentrations did not differ at any sampling time point; however, phosphorus and magnesium concentrations increased from baseline. Data were then pooled across weeks to evaluate changes due to distance and level of conditioning. Sodium, chloride, and magnesium concentrations increased progressively with distance ran, suggesting that these electrolytes are primarily being lost as exercising dogs salivate. Repletion of these minerals may assist in preventing exercise-induced electrolyte imbalance in physically active dogs.

Body Temperature Responses During Phases of Work in Human Remains Detection Dogs Undergoing a Simulated Deployment

Body temperature responses were recorded during phases of work (waiting-to-work in close proximity to search site, active work in a search site, and post-work recovery crated in vehicle) in human remains detection dogs during search training. State or federally certified human remains detection dogs (n = 8) completed eight iterations of searching across multiple novel search environments to detect numerous scent sources including partial and complete, buried, hidden, or fully visible human remains. Internal temperature (Tgi) of the body was measured continuously using an ingestible thermistor in the gastrointestinal tract. Mean total phase times were: waiting-to-work: 9.17 min (±2.27); active work: 8:58 min (±2:49); and post-work recovery: 24:04 min (±10.59). Tgi was impacted by phase of work (p < 0.001) with a small increase during active work, with mean peak temperature 39.4 °C (±0.34 °C) during that period. Tgi continued to increase for a mean of 6:37 (±6:04) min into the post-work recovery phase in the handler's vehicle with a mean peak Tgi of 39.66 °C (±0.41 °C). No significant increase in temperature was measured during the waiting-to-work phase, suggesting behaviors typical of anticipation of work did not appear to contribute to overall body temperature increase during the waiting-to-work recovery cycle. Continued increase of gastrointestinal body temperature several minutes after cessation of exercise indicates that risk of heat injury does not immediately stop when the dog stops exercising, although none of the dogs in this study reached clinically concerning body temperatures or displayed any behavioral signs suggestive of pending heat injury. More work is needed to better understand the impact of vehicle crating on post-work recovery temperatures in dogs.

A protocol for the determination of the maximal lactate steady state in working dogs

BACKGROUND

This study aimed to describe a test protocol for the determination of the maximal lactate steady state (MLSS) in dogs.

METHODS

Ten animals were submitted to a variable number of sessions (3 to 5), with a duration of 30 minutes each. Every session started with a warm-up period of 10 minutes at 7 km/h, at a 0% inclination. The treadmill was then set at a 5% inclination and at a constant speed, maintained for 20 m. In subsequent sessions, speed was increased or decreased 0.5 km/h. Blood samples were collected, and blood lactate (BL), heart rate (HR), rectal temperature (RT) and glycaemia were determined at rest (T0), after the warm-up (T1) and every 5 minutes until the end of the test (T2-T5).

RESULTS

Significant variations were observed in BL, HR and RT, when comparing values at rest and T1 with those at the MLSS level (P<0.01). Mean speed at MLSS was 14.6±1.47 km/h and BL was 2.7±0.45 mmol/L, a value below 4 mmol/L. A correlation between BL at MLSS and the visual lactate threshold was observed (0.87). A strong agreement between blood lactate levels at the MLSS level and LTv was also observed.

CONCLUSIONS

The present results consist, to the authors' knowledge, in the first description of a protocol to determine the MLSS in dogs. It provides information for exercise monitoring and training planning.

VOC pattern recognition of lung cancer: a comparative evaluation of different dog- and eNose-based strategies using different sampling materials

Background: It has been reported that canine scent tests offer the possibility to screen for cancer. Assuming that breath samples can be collected with carrier materials, we tested the practicability of different carrier materials to be presented to dogs and validated and compared results with an electronic nose (eNose). Moreover, we hypothesized that cancer detection ability of dogs differs according to their working experience. Methods: In a methodological approach, two dog teams participated, one using experienced working dogs and the other ordinary household dogs to find the most qualified dogs and training method. To find best carrier material for breath sampling we compared charcoal containing glass tubes and fleece masks. In a second validating part, experienced working dogs were trained with improved training strategies. For breath sampling, two different, previously successfully tested fleece-based carrier materials were used: one was used with the dog team and both materials were compared with eNose. Results: In the methodological approach, it turned out that the charcoal-based sampling strategy qualified not sufficiently for VOC-detection. Moreover, we could determine that using experienced working dogs provided several advantages. Overall results of dogs in the validating part regarding specificity were 83%, regarding sensitivity 56%, but with great variability among dogs. Using eNose for breath analysis collected with both fleece carrier materials, specificity was 97% and sensitivity 89-100%. Conclusion: Our data confirmed that the diagnostic accuracy of dogs depended on the type of dog training and on the carrier materials. A comparison of breath samples analysis with an eNose achieved better results for both, sensitivity and specificity than for dogs. The use of fleece masks or fleeces in glass tubes as a sampling material can be recommended as successful VOC carriers, encouraging their use for clinical screenings.

Health and temperaments of cloned working dogs

Dogs serve human society in various ways by working at tasks that are based on their superior olfactory sensitivity. However, it has been reported that only about half of all trained dogs may qualify as working dogs through conventional breeding management because proper temperament and health are needed in addition to their innate scent detection ability. To overcome this low efficiency of breeding qualified working dogs, and to reduce the enormous costs of maintaining unqualified dogs, somatic cell nuclear transfer has been applied in the propagation of working dogs. Herein, we review the history of cloning working dogs and evaluate the health development, temperaments, and behavioral similarities among the cloned dogs. We also discuss concerns about dog cloning including those related to birth defects, lifespan, and cloning efficiency.

Identifying and Resolving End of Session Cues in Substance Detection Canine Training

When training and working a substance detection canine, a trained final response should be performed immediately upon recognition of odor (Generally, a 1–3 s window is preferred within our detection practices). Typical canine training places much emphasis on planning and setting up training scenarios to achieve specific objectives but not much consideration is given to how to end a training session. When the canine fails to maintain criteria, trainers are left trying to determine the cause of poor performance. One consideration often overlooked is a phenomenon called End of Session Cueing that may exist in detection training whereby a previously trained canine no longer responds to odor because it has taken on aversive association. This may be due to several factors associated with motivation. The sequence of events at the end of a session can be as equally important to maintain motivation for the task of scent detection in future sessions. This paper will identify and examine multiple factors associated with “End of Session Cues” in working dogs, how they may be responsible for poor final response performance and discuss potential strategies to address them.

Working Dogs Drinking a Nutrient-Enriched Water Maintain Cooler Body Temperature and Improved Pulse Rate Recovery After Exercise

Exercise-related physiological changes were evaluated in hydrated, exercise-conditioned working dogs with free access to tap water (TW) with or without a nutrient-enriched water supplement (NW). Physiological samples and measures were collected before and after work-related field tasks in a warm and moderately humid ambient environment. In a cross-over design study, 12 dogs (age range 8-23 months) were evaluated on 3 separate occasions within each period with exercise bouts up to 30 min, on days -4, 3, and 11. Dogs were offered either ad libitum TW or portion-controlled NW daily plus ad libitum TW. Prior to and serially after exercise, pulse rate (PR), core (BT_core) and ear (BT_ear) temperature were recorded. Urine was collected first thing in the morning, whereas blood samples collected and body weight (BW) recorded pre- and immediately post exercise. Ambient temperature was above 21.7°C (71°F) and relative humidity ranged from 36 to 76%. Activity parameters, AM urine measures, post-exercise percent change of BW, resting PR and resting BT_core did not differ between treatment groups on any exercise day. At the completion of exercise, mean BT_core for all dogs ranged from 104.8 to 105.6°F. Immediate post-exercise BT_ear was always lower compared to BT_core and means ranged from 103.3 to 104.0°F. The effect of time was highly significant (P < 0.001) for both BT measures with both BT_core and BT_ear recovering to resting levels by 60 min post exercise. PR and several blood values showed a significant main effect of time. Over the recovery period, dogs in the NW group had lower mean BT_ear and PR by 0.6°F and 3.4 bpm, respectively. Daily ingestion of a NW in combination with free access to TW can reduce the post-exercise-related BT_core and BT_ear hyperthermia, and improve pulse rate recovery following exercise in this population of working dogs undergoing 30 min bout of exercise.

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.

Evaluation of Three Hydration Strategies in Detection Dogs Working in a Hot Environment

Physical activity in hot environments can increase the risk of heat stress or heat stroke in dogs. Heat tolerance is influenced by acclimatization to the environment, physical fitness, and hydration state. Three common strategies to promote hydration in working dogs are free access to water (W), oral electrolyte solutions (OESs), and administration of subcutaneous fluids (SQs). None of these methods have been compared for safety or efficacy in a working environment. In a cross-over design, seven vehicle-screening canines were randomly assigned to each of the three hydration strategies during working shifts at the Sarita, TX checkpoint. Physical, behavioral, and biochemical parameters were collected before, during, and after a work shift (mean 5.7 ± 0.8 h). Dogs were given 10 mL/kg oral W, 10 mL/kg chicken flavored OES, or 15 mL/kg of SQs initially followed by controlled access to W or OES. The dogs drank 15.61 ± 4.47 mL/kg/h of W and OES when in the OES group, compared to 7.04 ± 3.42 and 5.56 ± 4.40 mL of W, for the W and SQ groups, respectively. The median environmental temperature was 84.8°F (29.3°C). The median humidity was 70%. Based on mixed effects linear modeling, dogs in the OES and SQ groups had significantly higher total CO₂, and lower packed cell volume and total plasma protein at the end of the day. Creatinine increased a small but significant amount in the SQ group and decreased in the OES group. Searching behaviors were independent of hydration strategy but highly related to the dog specific factors of sex, breed, and activity level. Under conditions of controlled activity in moderate heat and humidity, dogs accustomed to the work and the environment were more likely to increase fluid consumption and hydration when provided a flavored OES. Potential benefits of OES and SQ were indirect and no adverse effects were documented for any of the hydration strategies tested.