Environmental Heat Exposure Among Pet Dogs in Rural and Urban Settings in the Southern United States

Abstract

With advancing global climate change, heat-related illnesses and injuries are anticipated to become more prevalent for humans and other species. Canine hyperthermia is already considered an important seasonal emergency. Studies have been performed on the risk factors for heat stroke in canine athletes and military working dogs; however there is limited knowledge on environmental risk factors for the average pet dog. This observational study explores variation in individually experienced environmental temperatures of pet dogs (N = 30) in rural and urban environments in central Alabama. Temperature data from dogs and their owners was collected using wearable personal thermometers. Demographic data on the dogs was collected using a brief survey instrument completed by their owners. Dogs included in the study varied in signalment, activity level, and home environment. Linear mixed effects regression models were used to analyze repeated measure temperature and heat index values from canine thermometers to explore the effect of environmental factors on the overall heat exposure risk of canine pets. Specifically, the heat exposures of dogs were modeled considering their owner's experienced temperatures, as well as neighborhood and local weather station measurements, to identify factors that contribute to the heat exposure of individual dogs, and therefore potentially contribute to heat stress in the average pet dog. Results show hourly averaged temperatures for dogs followed a diurnal pattern consistent with both owner and ambient temperature measurements, except for indoor dogs whose recordings remained stable throughout the day. Heat index calculations showed that owners, in general, had more hours categorized into the National Weather Station safe category compared to their dogs, and that indoor dogs had a greater proportion of hours categorized as safe compared to outdoor dogs. Our results suggest that the risk of the average pet dog to high environmental heat exposure may be greater than traditional measures indicate, emphasizing that more localized considerations of temperature are important when assessing a dog's environmental risk for heat-related injury or illness.

Risk Factors for Severe and Fatal Heat-Related Illness in UK Dogs—A VetCompass Study

“…Heat stress experienced both during the day and at night contribute to heat-related mortality in humans [ 54 ], with heat-sensitive sub-populations (including the elderly and hospital patients) most likely to be located in areas with the highest night-time temperatures [ 40 ]. We echo the suggestion by Moon et al [ 51 ] that traditional measures of local temperature, such as heat index data from local weather stations, are likely to underestimate the risk of heat exposure for dogs. Further research aimed at predicting heat risk for dogs in different locations and housing types is needed.…”

“…These data are therefore an estimation of the local environmental (shaded) conditions and are unlikely to fully represent the true conditions actually experienced by the dogs [ 40 ]. A recent US study compared ambient temperature data from thermometers mounted on dogs’ collars to neighbourhood and local weather station temperature records [ 51 ]. That study reported that the dog-mounted thermometers generally recorded lower ambient temperatures than the local weather station reported during the day for indoor housed dogs, but dogs housed outdoors in urban locations recorded higher local ambient temperatures than either the neighbourhood or regional weather stations.…”

“…Moon et al [ 51 ] also found that the temperatures recorded from the dog-mounted thermometers in urban environments were significantly higher than the concurrent weather station temperatures at night. This difference was attributed to reduced airflow within houses, resulting in hotter indoor temperatures than outdoor overnight.…”

Do intense weather events influence dogs' and cats' behavior? Analysis of owner reported data in Italy

“…Moreover, performance in animals falls below its optimum during cooling and warming (15). Since extreme weather events, including thunderstorms, torrential rains, and flooding, are predicted to rise in frequency and severity (16), increased attention is necessary to identify and implement adaptation strategies (17). During last years, changes in temperatures and precipitation patterns have been evidenced in Italy, with events of extreme heat, torrential rains lasting for days and sudden and violent thunderstorms increasingly frequent (18), likely leading owners to change their routine based on the weather conditions.…”

“…To the authors' knowledge, only one study in English (26) has examined the potential environmental impacts related to a dog's entire life cycle. Few studies investigated the most common triggers of heat-related illness and injuries in dogs in the UK (7,17,27) and the environmental impacts of companion dog's and cat's food consumption (26). However, limited attention has been given to the environmental factors contributing to canine and feline behavioral changes.…”