was suggestive of HPA dysfunction. A decrease in peripheral lymphocyte numbers and an increase in neutrophil numbers, along with an increased neutrophil:lymphocyte ratio, is another well‐documented response to glucocorticoid release and has been proposed as another reliable method for evaluating the stress an animal may be experiencing (Davis et al. 2008).
Studies have shown that the average shelter dog does have higher levels of circulating cortisol than pet dogs that were sampled in their homes (Hennessy et al. 1997). Some studies of shelter dogs have found that circulating levels of cortisol return to normal within days to weeks, but others have found that HPA axis dysregulation develops in some dogs (Hennessy 2013).
Any single individual’s response to stress will vary as a result of several different factors such as genetics, temperament, experience, environment, and learning. For example, cats not socialized to people have been shown to be more likely to experience high levels of stress when exposed to people in a shelter setting (Kessler and Turner 1999a). Experiences during the first weeks of life have been shown to have profound effects on an animal’s ultimate ability to cope with stress (Foyer et al. 2013). The importance of the role of maternal stress on the developing offspring during the prenatal period is receiving an increasing amount of attention (Jensen 2014). Research in numerous species has demonstrated that when the gestating mother experiences stress, it can alter her behavior and affect the behavioral development of her young (Braastad et al. 1998; Chapillon et al. 2002; Champagne et al. 2006). Subsequently, her offspring often show a decreased ability to deal with stress: they may have some learning impairment and they may be more susceptible to the conditioning of fearful responses, especially to auditory stimuli (Ross et al. 2017). The individual’s perception of stress, which will also vary based on experience, is ultimately the most important factor that influences the effect of stress. Many potential stressors exist for the sheltered dog and cat. Table 4.1 provides a summary of common shelter stressors and behavioral signs of stress.
4.4.1 Cats
Several studies have evaluated the stressors impacting shelter and laboratory cats. Shelter cats exhibiting higher stress scores are at higher risk of developing upper respiratory tract infections (Tanaka et al. 2012). One study reported that feigned sleep may be a coping mechanism seen in stressed shelter cats (Dinnage 2006). An increased need for restorative sleep has been demonstrated in both humans and animals exposed to physiological or biological stress (Rampin et al. 1991; Rushen 2000). These data suggest that while cats may appear to be the most relaxed of animals, they may, in fact, suffer the highest levels of stress.
The stress level of most kenneled cats will decrease over the first few days to weeks. One study demonstrated that two‐thirds of cats will adjust well within the first two weeks (Kessler and Turner 1997). The same study demonstrated that about 4% of cats maintained a high level of stress for the entire study period, suggesting that for a small segment of the feline population, housing in the shelter for any extended period may not be in the best interest of that individual (Kessler and Turner 1997).
Table 4.1 Common Stressors and Behavioral Signs of Stress in Shelter Dogs and Cats (Jones and Josephs 2006; Horváth et al. 2008; Beerda et al. 1998, 1999; Carlstead et al. 1993; Kessler and Turner 1999b; Tanaka et al. 2012; Kessler and Turner 1997; Dinnage 2006).
| Common stressors | Behavioral signs of stress |
|---|---|
| Dogs | |
| Separation from familiar social figures Loud noises Restraint and unpredictable handling Confinement Elimination on unfamiliar surfaces and/or in living space Sounds and odors associated with the stress and aggressive behavior of other dogs Altered routines Immersion in novel environment, surrounded by novel stimuli | Trembling Crouching Oral behaviors (e.g., snout licking, swallowing, smacking) Yawning Restlessness Lowered body posture Increased autogrooming Paw lifting Vocalizing Repetitive behavior Coprophagy |
| Cats | |
| Unpredictable handling and husbandry routines Increased density of group‐housing Inability to hide | Decreased food intake and weight loss Less play and active exploratory behaviors More time awake and alert Attempting to hide Behavioral apathy Vocalization Escape behaviors Aggressive behavior Feigned sleep |
4.5 The Behavior of Pain
Recognizing the behavioral signs of pain in non‐verbal species is challenging. Because animals can’t tell us when they experience pain, it is critical to train shelter staff to recognize their non‐verbal signs if we are to ensure good welfare. A number of problem behaviors can occur in dogs and cats in response to pain. These can include irritability (increased sensitivity and reactivity to stimuli), aggressiveness, restlessness, excessive vocalization, changes in activity level, and an increase in anxiety‐related behaviors. In an animal that was previously behaviorally stable, any abrupt changes in behavior can signal pain, but they are especially noteworthy when occurring in a middle‐aged or geriatric animal.
Pain in the shelter animal may be even more difficult to identify since caretakers may not be familiar enough with an individual to determine what is normal or abnormal for that animal. To further complicate matters, physiologic responses to pain and stress can be similar, and because animals entering a shelter are likely to experience stress, this may make differentiating the two very difficult. In addition, it is normal for most animals to try to mask their pain, and they may be even more likely to do this when placed in a stressful situation.
The objective signs of medical problems that typically result in pain cannot always be identified with a physical exam, radiographs, laboratory work, and so forth. Therefore, it is generally accepted that behavioral rather than physiological signs are the most important parameters we should attend to when evaluating pain in animals (Epstein et al. 2015). We should also always keep in mind that if a procedure, injury, or illness causes pain in humans, then it would be wise to assume that it causes pain in dogs and cats as well.
Different animals will manifest pain differently, and there is no single behavior that can be considered pathognomonic for pain. Neither does the absence of certain behaviors always indicate the absence of pain. Many behaviors considered to be indicative of pain can also occur due to anxiety or fear in both dogs and cats. In addition, the presence of other diseases can change the appearance of pain behaviors. Several studies have found that subjective behavioral measures can be used successfully to identify pain in animals and subsequently evaluate the efficacy of treatment (Holton et al. 1998; Cloutier et al. 2005; Bennett and Morton 2009). However, more research is needed to refine and validate some of the current methods. Because some diagnostic capabilities may be limited in a shelter situation, anecdotal information suggests that when in doubt, a course of treatment with analgesics and/or anti‐inflammatories may be warranted if a painful condition is suspected. Failure to recognize pain is a significant welfare concern. Training shelter staff is a crucial task for shelter management to ensure that staff can reliably and consistently recognize even the most subtle signs of pain in animals. Table 4.2 provides a summary of behavioral signs of pain in dogs and cats.
4.5.1 Cats
Improving our ability to identify pain in cats is important for many reasons. Degenerative joint disease (DJD) is more common in cats than previously believed (Perry 2014). Although some cats will appear pain free and still have joint abnormalities visible on radiographs (Monteiro and Steagall 2019), several studies have shown that signs of pain and discomfort associated with DJD commonly occur prior to the
