Salivary cortisol concentrations and behavior in a population of healthy dogs hospitalized for elective procedures

Abstract

Identification of severe stress in hospitalized veterinary patients may improve treatment outcomes and welfare. To assess stress levels, in Study 1, we collected salivary cortisol samples and behavioral parameters in 28 healthy dogs hospitalized prior to elective procedures. Dogs were categorized into two groups; low cortisol (LC) and high cortisol (HC), based on the distribution of cortisol concentrations (< or ≥ 0.6 µg/dL). We constructed a stress research tool (SRT) based on three behaviors, (head resting, panting and lip licking) that were most strongly related to salivary cortisol concentrations. In Study 2, we collected salivary cortisol samples from 39 additional dogs, evaluated behavior/cortisol relationships, assigned each dog to an LC or HC group, and tested the ability of the SRT to predict salivary cortisol. Median (interquartile range) salivary cortisol concentrations were not different between Study 1 (0.43 µg/dL, 0.33 to 1.00 µg/dL) and Study 2 dogs (0.41 µg/dL, 0.28 to 0.52 µg/dL). The median salivary cortisol concentration was significantly lower (P ≤ 0.001) in LC versus HC dogs in each study; (Study 1 LC: 0.38 µg/dL, (0.19 to 0.44), n = 19, HC: 2.0 µg/dL, (1.0 to 2.8), n = 9, and Study 2 LC: 0.35 µg/dL, (0.25 to 0.48), n = 28, HC: 0.89 µg/dL, (0.66 to 1.4), n = 7). In Study 1, three behaviors were found to be associated with salivary cortisol concentrations. Duration of head resting was negatively associated with salivary cortisol (ρ = −0.60, P = 0.001), panting and lip licking were positively associated with cortisol (ρ = 0.39, P = 0.04, and 0.30, P = 0.05, respectively), Head resting (p = 0.001) and panting (p = 0.003) were also associated with LC/HC group assignment. In Study 2 dogs, the three behaviors correlated (but not significantly) with salivary cortisol concentration; of the three, only head resting was significantly associated with LC/HC group assignment (P = 0.03). The SRT derived from Study 1 was effective at prediction of salivary cortisol concentrations when applied to 20 min but not 2 min of behavioral data from Study 2. Additionally, we note that dexmedetomidine and butorphanol sedation more than 6 h prior to measurement was found to be significantly (P = 0.05) associated with lower salivary cortisol concentrations when compared to unsedated dogs. Our work offers support for eventual construction of a rating tool that utilizes the presence or absence of specific behaviors to identify higher salivary cortisol concentrations in dogs subjected to hospitalization, which may be tied to greater psychogenic stress levels. Future work to investigate the effects of stress on dogs and its mitigation in clinical situations may be approached by studying a combination o f parameters, and should consider the possible beneficial effects of sedatives.

Salivary cortisol concentration in healthy dogs is affected by size, sex, and housing context

“…It is likely that the genetic background of breed other than live weight is a factor affecting the responsiveness of the dogs to environmental stimulations (Houpt, 2007;Spady et al, 2008). From the best of our knowledge, no results are published for the effect of breed or size on cortisol secretion, but in other researches, the authors recognized the need to randomize dogs according to breed and size to avoid potential interferences (Bennet and Hayssen, 2010;Hekman et al, 2012). Furthermore, Vas et al (2007) measured attention deficit hyperactivity disorder using a human questionnaire and found that small-sized dogs showed significantly differences in their activity/impulsive score in comparison to large-sized dogs.…”

“…According to Beerda et al (1998), the concentration of salivary cortisol increases from a mean basal value of 2.16-4.68 and up to 6.01 ng/mL in dogs exposed to different stimulations. In a study of Hekman et al (2012) with dogs selected among a population of healthy patients hospitalized for an elective procedure, median and mean cortisol concentrations in saliva were 4.3 and 8.7 ng/mL, respectively. These values are above the 75 percentile of the present study (Table 2), confirming that saliva cortisol is a marker of HPA axis activation in response to the environment.…”

“…After sampling, the swabs were introduced into tubes specifically designed to avoid cortisol sequestration (Salivette; no. 51.1534, Sarstedt, Nümbrecht, Germany), temporally stored in an iced box before the final storage at À20 C. Before analysis, performed within 15 days, swabs were thawed and centrifuged at room temperature at 1500Âg for 15 minutes to obtain clear saliva, which was used for cortisol determination using an enzyme immunoassay kit (Salimetrics, State College, PA) (Hekman et al, 2012). Samples were assayed in duplicate, using 25 mL of sample per well.…”

Influence of low stress handling during clinical visit on physiological and behavioural indicators in adult dogs: a preliminary study

“…The influence on rectal temperature could be related to a different temperature perception through the examination table (lower table temperature during TT than during LSH visits) but many conditions, including digestion, peristaltic movements, fecal masses and physical activity may affect rectal temperature (Rexroat et al 1999;Rizzo et al 2017). Lip licking has been previously related to salivary cortisol concentrations in hospitalized dogs (Hekman et al 2012) and could be useful for the evaluation of acute stress levels in a social context (Beerda et al 1998). Limitations to the findings of this study are the small number of subjects, the adult age of enrolled dogs and the absence of interaction with an owner.…”

Nutrición clínica de perros hospitalizados: Revisión

“…Em alguns casos oferecer alimentos palatáveis e aquecidos é suficiente para que o animal consuma a quantidade necessária de nutrientes e calorias (Nelson and Couto, 2015). O simples fato de dar alta ao paciente e a presença do proprietário também podem estimular o animal a voltar a se alimentar espontaneamente, já que eles manifestam comportamento de estresse em ambientes hospitalares, afetando negativamente a ingestão de alimentos mesmo em animais saudáveis (Hekman et al, 2012).…”