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Baseline cortisol concentrations are routinely used to screen dogs for hypoadrenocorticism (HOC); this diagnosis must then be confirmed with an ACTH stimulation test. A baseline cortisol concentration less than 55 nmol/L (2 μg/dL) is highly sensitive for HOC but lacks specificity, with a false positive rate >20%. Many dogs with nonadrenal disease are therefore subjected to unnecessary additional testing. It was hypothesized that exposure to an unpleasant auditory stimulus before sample collection would improve the specificity of baseline cortisol measurements in dogs with nonadrenal disease by triggering cortisol production. Twenty-eight healthy client-owned dogs were included in the study, with a median age of 4 yr (range 2–9 yr) and a median weight of 20 kg (range 10–27 kg). Dogs were ineligible for inclusion if they had received short- or long-acting glucocorticoids within the previous 30 and 90 d, respectively. Dogs were randomly assigned to group 1 (control; no noise; n = 7), group 2 (brief noise: n = 10), or group 3 (long noise: n = 11). Each dog and owner were directed to a secluded area for approximately 15 min. Group 1 sat in relative quiet, exposed only to the background sounds of a veterinary hospital. Group 2 were exposed to the sound of a wet-dry vacuum in an adjacent hallway during the first 3 min of this period. Group 3 were exposed to random bursts of wet-dry vacuum noise during this period. At the end of the test interval, each dog was escorted to an adjacent examination room for blood collection. Samples were processed within 15 min; serum was frozen at −80°C before measurement of cortisol concentrations. Median serum cortisol concentrations and the proportion of dogs with results <55 nmol/L were similar for the 3 groups. The study hypothesis that exposure to the noise of a wet-dry vacuum cleaner would consistently drive baseline serum cortisol concentrations above 55 nmol/L in dogs with apparently normal adrenal function was therefore rejected. [ABSTRACT FROM AUTHOR]

Background The ACTH stimulation has low sensitivity for the diagnosis of hypercortisolism possibly as a result of biological and analytical variability. Hypothesis/Objectives To report the components of biological and analytical variability in serum cortisol concentration post- ACTH stimulation ([cortisol]) in healthy dogs. Animals Fourteen healthy harrier hound dogs. Methods The data were extracted from a separate, prospective, randomized, double-blinded, controlled discovery study in which dogs treated with vehicle control and 4 different doses of cortisone acetate ( CA) for 7 days had an ACTH stimulation test performed to confirm the dose-dependent effect of CA. The index of individuality (IoI), the critical difference between sequential measurements ( C D), and the number of measurements required to assess the homeostatic set point ( HSP) of [cortisol] with confidence intervals ( CI) of 90 and 95% were estimated. Results The IoI was equal to 1.1 and the C D was 3.3 μg/ dL (92 nmol/L). The number of measurements required to assess the HSP of [cortisol] with CI of 90 and 95% were 3 and 15, respectively. Additionally, mean [cortisol] was higher in males than in females (13.3 ± 4 μg/ dL [366 ± 114 nmol/L] vs. 11.5 ± 2.5 μg/ dL [318 ± 65 nmol/L], respectively; P = .046). As expected, treatment with CA resulted in a dose-dependent suppression of [cortisol]. Conclusions and Clinical Importance False-negative test results in hypercortisolism could occur when [cortisol] is outside of the individual's HSP and within the reference interval. The large C D emphasizes the importance of assessing clinically relevant parameters in the diagnosis and monitoring of HC. [ABSTRACT FROM AUTHOR]

Along the perinatal period, in mammals, cortisol (C) plays a pivotal role in the final intrauterine fetal maturation and in the early neonatal adaptation. Because of the scarce knowledge about canine perinatology, the present study was aimed to assess the C concentrations in amniotic and allantoic fluids collected, without invasiveness, from small-sized, purebred newborn puppies born by elective cesarean section, at term of pregnancy. Possible correlations between fetal fluid C concentrations and maternal parity, litter size, birth weight, Apgar score, were evaluated. In addition, the possible effect of fetal fluid C concentrations on newborn survival at 24 hours of age, and the effect of the litter or the newborn gender on fetal fluid C concentrations were also assessed. The results, obtained from 50 born alive, normal-weight puppies, without gross physical malformation, showed that C concentration was higher in allantoic than in amniotic fluid (P < 0.01), even if a strong positive correlation between the two fluids C concentration was found (P < 0.0001; R = 0.83). Neither amniotic nor allantoic C concentrations were correlated to maternal parity, litter size, birth weight, and Apgar score. Interestingly, higher amniotic (P < 0.05), but not allantoic, C concentrations were found in puppies not surviving at 24 hours after birth. Therefore, it could be suggested that this parameter may be useful for the recognition, at birth, of puppies needing special surveillance during the first day of age. A significant (P < 0.001) effect of the litter in both amniotic and allantoic C concentrations was found. In conclusion, the present results showed that in small-sized purebred puppies, born at term by elective cesarean section, the exact fetal, maternal, or placental source contributing to fetal fluid C concentrations remains to be clarified. From a clinical perspective, however, the evaluation of amniotic C concentration at birth seems useful for the detection of puppies that need special surveillance during the first 24 hours of age, and should be coupled to the early newborn evaluation by Apgar score. However, the small total number of newborns, and especially of the dead puppies enrolled in the present study, suggests that further, more-focused investigations on a large number of subjects are needed before the method could be considered for application in the clinical practices. [ABSTRACT FROM AUTHOR]

Separation anxiety (SA) is a serious behavioral problem in dogs. In this study, salivary cortisol was studied to determine if the owner's odor or voice could reduce SA in dogs. Twenty-eight dogs with SA were divided into three groups: group 1 (control), group 2 (with owner's clothes during the separation period; SP) and group 3 (a recording of the owner's voice was played during SP). The dog's saliva was collected after the owner and their dog were in the experimental room for 5 min (PRE). The dog was then separated from the owner for 20 min and saliva collected four times at intervals of 5 min (SP1-4). Finally, the owner was allowed back into the room to calm the dog for 5 min, after which saliva was collected (POST). Evaluation of salivary cortisol concentrations by ELISA revealed that the ratios of SP1 concentration to PRE or POST concentrations were significantly higher in group 1 than in group 2 or 3. Additionally, the concentrations of SP1-PRE and SP1-POST among groups differed significantly. These findings indicate that the owner's odor or voice may be helpful to managing stress in dogs with SA. [ABSTRACT FROM AUTHOR]

Background There are breed differences in several blood variables in healthy dogs. Objective Investigate breed variation in plasma endothelin-1 ( ET-1) concentration, plasma renin activity, and serum cortisol concentration. Animals Five-hundred and thirty-one healthy dogs of 9 breeds examined at 5 centers (2-4 breeds/center). Methods Prospective observational study. Circulating concentrations of ET-1 and cortisol, and renin activity, were measured using commercially available assays. Absence of organ-related or systemic disease was ensured by thorough clinical investigations, including blood pressure measurement, echocardiography, ECG, blood and urine analysis. Results Median ET-1 concentration was 1.29 (interquartile range [ IQR], 0.97-1.82) pg/mL, median cortisol concentration 46.0 ( IQR, 29.0-80.8) nmol/L, and median renin activity 0.73 ( IQR, 0.48-1.10) ng/ mL/h in all dogs. Overall, breed differences were found in ET-1 and cortisol concentrations, and renin activity ( P < .0001 for all). Pair-wise comparisons between breeds differed in 67% of comparisons for ET-1, 22% for cortisol, and 19% for renin activity, respectively. Within centers, breed differences were found at 5/5 centers for ET-1, 4/5 centers for cortisol, and 2/5 centers for renin activity. Newfoundlands had highest median ET-1 concentration, 3 times higher than Cavalier King Charles Spaniels, Doberman Pinschers, and Dachshunds. Median renin activity was highest in Dachshunds, twice the median value in Newfoundlands and Boxers. Median cortisol concentration was highest in Finnish Lapphunds, almost 3 times higher than in Boxers. Conclusions and Clinical Importance Breed variation might be important to take into consideration when interpreting test results in clinical studies. [ABSTRACT FROM AUTHOR]

Background The ACTH stimulation test is used to evaluate the adrenocortical reserve. Recently, the availability of the synthetic ACTH formulation was limited, causing major problems in clinical practice. Objectives The objective of this study was to evaluate poststimulation peak cortisol concentrations and the duration of the stimulatory effect of a depot ACTH preparation in dogs. Animals Twenty-two healthy dogs, 10 dogs with suspected hypoadrenocorticism ( HA) and 15 dogs with suspected hyperadrenocorticism ( HC). Methods Prospective study. An ACTH stimulation test using a synthetic depot tetracosactide, administered intramuscularly (5 μg/kg or at least 0.1 mL) was performed. Blood samples for determination of cortisol were taken immediately before and 1, 2, 3, 4, 6, and 24 hours after stimulation. Results Peak cortisol concentrations were reached after 2-4 hours in all dogs. Cortisol concentrations 1 hour after stimulation were >9 μg/dL in all healthy dogs and >5 μg/dL in all dogs in which HA was excluded. None of the dogs with HA showed a cortisol-increase above the detection-limit of the assay. After 6 hours, cortisol concentrations had decreased in the healthy and HC group and were back to baseline after 24 hours. Conclusions and Clinical Importance The depot formulation can be used in place of the short-acting ACTH to evaluate the adrenocortical reserve. Blood for peak cortisol concentrations should be drawn 3 hours after stimulation in cases in which HC is suspected; in HA-suspected cases, blood sampling can take place after 1 hour. As the stimulatory effect is gone after 24 hours, interference with other hormonal tests is unlikely after that time. [ABSTRACT FROM AUTHOR]

Motivation–structural rule theory predicts that a sender producing harsh, low frequency sounds directed at a conspecific modifies the receiver's behaviour, in part, by communicating its willingness to escalate to an attack. Motivation–structural (MS) rules generally assume that receivers respond to this signal by retreating because of the threat encoded in the acoustic characteristics of the vocalisation. This assumption does not consider if alternative behavioural responses exist or how internal and environmental contexts affect receivers. This becomes an area for potential development of the MS theory when acknowledging that physiological and behavioural reactions may be related to distinct antithetical responses, such as Passive and Proactive coping strategies. To test if aggressive sound stimuli elicit consistent retreat responses by receivers, 42 dogs from shelters and private dog breeders were graded on behaviour and measures of salivary cortisol (a stress related steroid hormone) in response to an agonistic growl from an unknown, similarly sized conspecific. Results revealed that 52.4% (22/42) of dogs displayed retreat behaviours (Passive response), 33.3% (14/42) actively approached the growl source (Proactive response) and 14.3% (6/42) neither approached nor retreated (Neutral response). Post-test cortisol levels differed significantly between dogs in the Proactive, Passive and Neutral categories. Passively responding dogs averaged an 80% change in cortisol levels, Proactive dogs exhibited a 16.5% average cortisol change and Neutral responders displayed only a 6.4% change in cortisol. Although shelter dogs exhibited greater changes in cortisol, they did not differ significantly from the privately-owned dogs. This study verified that overt, observable behavioural responses reflect the physiological stress responses as measured by cortisol changes exhibited by domestic dogs. Results also suggested that experiences may influence how dogs to threatening stimuli from conspecifics respond—behaviourally and physiologically. A protocol providing a simulated threatening interaction with a dog, which does not bring the animals into direct contact, would have important implications for shelter staff in terms of how dog–dog introductions are managed, housing arrangements, potential training, matching dogs to owners and what advice shelter staff could offer to new owners. [ABSTRACT FROM AUTHOR]

The effect of animal-assisted activities (AAA) on the animal participants has been minimally investigated, and the welfare of these animals has been questioned. To enhance our understanding of these animals’ welfare, we measured cortisol collected from serial saliva samples of 15 healthy adult dogs registered with an AAA organization. We collected saliva every 30 min before, during, and after a standardized 60-min session across three settings: an AAA session (activity) for college students in the communal area of a residence hall, a novel session located in a novel room without interaction with a stranger, and a home session inside each handler's own home. Each session was videotaped, and specific behaviors during 5-min petting interactions were coded. Salivary cortisol levels were significantly higher in the novel setting (0.397 μg/dL) compared to activity (0.257 μg/dL) and home (0.213 μg/dL) settings at time 30 min ( P = 0.01 and P = 0.03, respectively). Dogs exhibited significantly more standing (59% vs 0%, P = 0.008) and ambulating (5.6% vs 0%, P = 0.001) behavior in the activity setting compared to the home at time 30 min, as well. Salivary cortisol level was negatively correlated with panting ( P = 0.02) and standing ( P = 0.02) at specific time points in the novel and activity settings, respectively. During the 60-min AAA session, salivary cortisol concentration and stress-associated behavior were not statistically different compared to when dogs spent the same amount of time in the home setting, suggesting that they were not distressed when participating in the AAA sessions. The predictability of the environment may be an important consideration when evaluating the effect of AAA on dogs. [ABSTRACT FROM AUTHOR]