Reactivity In Dogs Research Articles

Noise reactivity and firework fear in dogs

Noise reactivity and firework fear are well-known and often discussed topics among dog owners. The prevalence of noise reactivity varies a lot between different dog breeds; in certain breeds, as many as 50% of all dogs are affected at some level. Even though the prevalence of noise reactivity is high, little is known about the genetic background of noise reactivity in dogs. This article provides a brief introduction to behavioural genetics and the genetics behind noise reactivity and firework fear, some of the animal welfare issues related to extreme fear of noise, and sheds light on the possibilities of reducing the prevalence through systematic breeding.

Size, skull shape and age influence the temperament of domestic dogs

Studies have investigated the relationship between dogs’ morphological characteristics and behavioural dimensions, but little is discussed about this relationship in the context of dogs’ responses to emotion eliciting stimuli and temperament. Based on the assumption that the developmental trajectory of behaviour and emotion processing is impacted by the interaction between organisms and environment, we analysed whether dogs’ characteristics – that determine how they perceive and interact with their surroundings – affect temperament profiles. We looked at size, height, weight, skull morphology, age, sex, reproductive status, and breed of a sample of Brazilian domestic dogs’ and their temperament (measured as Positive and Negative Activation), obtained via the PANAS questionnaire for dogs. We tested possible main effects and first-order interactions in linear mixed models. Younger dogs showed higher positive activation (i.e. sensitivity to positive stimuli; play and treats). For short snouted dogs, the older the dog, less was the negative activation (i.e. sensitivity to negative stimuli; punishment). And for long snouted dogs, larger dogs showed lower negative activation. Weight alone also showed an effect, with heavier dogs having less sensitivity to negative stimuli. Overall, our study demonstrated how morphology and age are important factors that influence temperament expression and emotional reactivity in dogs.

Neuroendocrine and Cardiovascular Activation During Aggressive Reactivity in Dogs.

Our aim was to investigate cardiovascular activation by measuring changes in facial and body surface temperature using infrared thermography, and neuroendocrine activation using salivary cortisol (CORT) and serotonin concentration (SER) in dogs exhibiting aggressive reactivity in real time. Based on two factors, owner-reported past aggressive behaviors, and detailed behavioral observations collected during a Socially Acceptable Behavior test consisting of 16 subtests and, each individual was categorized as aggressive or non-aggressive. CORT and SER showed no difference in neuroendocrine activity between dogs, but aggressive dogs with higher levels of aggression were found to have lower SER. Aggressive dogs also had an increase in facial temperature from pre-test values. The discovery of a correlation between tail wagging and left tail wagging with aggression level and aggression-related behaviors in aggressive dogs is further evidence of the right hemisphere specialization for aggression previously reported in the literature. This study provides the first evidence that both cardiovascular and neuroendocrine systems are activated during an active act of aggression in dogs.

Genetic parameters for noise reactivity in standard poodles

The aim of this study was to increase knowledge on the genetic background of noise reactivity in dogs, with a study on heritability based on owner-collected data on standard poodles’ degree of fear of sudden loud noises and fireworks. Previous studies have shown significant breed differences, and we expected to find significant heritability for noise reactivity. 1148 standard poodles are included in the study. The estimated heritabilities are between 0.09 and 0.16. Reaction to sudden loud noises and fireworks are genetically highly correlated (rg > 0.95).

Orienting asymmetries and physiological reactivity in dogs' response to human emotional faces.

Recent scientific literature shows that emotional cues conveyed by human vocalizations and odours are processed in an asymmetrical way by the canine brain. In the present study, during feeding behaviour, dogs were suddenly presented with 2-D stimuli depicting human faces expressing the Ekman's six basic emotion (e.g. anger, fear, happiness, sadness, surprise, disgust, and neutral), simultaneously into the left and right visual hemifields. A bias to turn the head towards the left (right hemisphere) rather than the right side was observed with human faces expressing anger, fear, and happiness emotions, but an opposite bias (left hemisphere) was observed with human faces expressing surprise. Furthermore, dogs displayed higher behavioural and cardiac activity to picture of human faces expressing clear arousal emotional state. Overall, results demonstrated that dogs are sensitive to emotional cues conveyed by human faces, supporting the existence of an asymmetrical emotional modulation of the canine brain to process basic human emotions.

Is your dog empathic? Developing a Dog Emotional Reactivity Survey.

Dogs' seemingly empathic behaviour attracts general and scientific attention alike. Behaviour tests are usually not sufficiently realistic to evoke empathic-like behaviour; therefore we decided to ask owners about their experiences with their dogs in emotionally loaded situations. Owners from Hungary (N = 591) and from Germany (N = 2283) were asked to rate their level of agreement on a 1–5 Likert scale with statements about the reactivity of their dogs to their emotions and to other dogs’ behaviour. We created two scales with satisfactory internal reliability: reactivity to the owner’s emotion and reactivity to other dogs’ behaviour. Based on an owner-dog personality matching theory, we hypothesised that the owner’s empathy, as measured by the subscale on the cooperativeness character factor of the human personality, will correlate with their dog’s emotional reactivity in emotionally loaded situations. In addition we also examined how anthropomorphism, contagious yawning, attitude toward the dog are related to emotional reactivity in dogs as perceived by the owner. In addition we examined how owners rate dog pictures. We found that the scale scores were largely independent from demographic and environmental variables like breed, sex, age, age at acquiring, keeping practices, training experiences and owner's age. However, anthropomorphic and emotional attitude of the owners probably biased the responses. In the German sample more empathic owners reported to have more emotionally reactive dog, as expected by the personality matching theory. More empathic owners reported to have fewer problems with their dogs and they rated a puppy picture as more cute in both countries. 62% of owners from Hungary and 36% of owner from Germany agreed with the statement “My dog is more important for me than any human being”. In Germany, more empathic owners agreed less with this statement and indicated that their dogs have a tendency for contagious yawning. Owners whose attitudes toward their dogs were anthropomorphic (agreed more with the statement that “My dog thinks like a child”), perceived their dogs as more reactive to their emotions. This findings highlights the importance of testing the attitudes of the respondents when they assess the personality and the emotions of animals. The criterion validity of the Dog Emotional Reactivity Survey should be confirmed by objective behavioural tests.

Autonomic, endocrine and behavioural responses to thunder in laboratory and companion dogs

Dogs are highly sensitive to sound stimuli, especially fireworks, firearms, and thunder, and therefore these sounds are used as models of stress reactivity in dogs. Companion and laboratory dogs may respond differently to stressful stimuli, due to differences in management and their relationship with humans. Therefore, the reactivity of beagle dogs (laboratory) and companion dogs to an acute acoustic stress model was studied by analysing the heart rate variability (HRV; cardiac interval values), serum cortisol levels and various behavioural parameters. Eight beagles and six privately owned dogs with no history of phobia to thunder were used. The sound stimulus consisted of a standardized recording of thunder for 2.5min with a maximum intensity of 103–104dB. To evaluate the HRV, cardiac intervals were recorded using a frequency meter (Polar RS800CX model), and later the data were analysed using CardioSeries 2.4.1 software. In both laboratory and companion dogs, thunder promoted an increase in the power of the LF band of the cardiac interval spectrum, in the LF/HF ratio and in the HR, and a decrease in the power of the HF band of the cardiac interval spectrum. Companion dogs showed higher cortisol levels, than beagles, independently of the time point studied and a significant increase in the cortisol levels 15min after acoustic stress, while beagles did not show any alterations in their cortisol levels in response to the sound. On the other hand, beagles showed higher scores in the trembling, hiding, vigilance, running, salivation, bolting and startle parameters than companion dogs. Our results showed that independently of the sound stimulus, companion dogs had higher cortisol levels than laboratory dogs. Furthermore, the sound stimulus induced a marked autonomic imbalance towards sympathetic predominance in both laboratory and companion dogs. However a significant increase in the cortisol was observed only in companion dogs. On the other hand, in general the behavioural response was more pronounced in laboratory dogs than in companion dogs.

Is noise reactivity reflected in auditory response variables, including those that measure cognition, in dogs? Initial findings

Noise reactivity and noise phobia are anxiety- and panic-related conditions in dogs that may affect up to 50% of dogs across their lifetime. Affected dogs show a range of signs of distress including trembling, freezing, panting, social withdrawal, pacing, salivating, and escape behaviors. Noise reactivity and phobia have been shown to be comorbid conditions, and their presence may increase the risk and severity of other anxiety-related conditions. Anxiety disorders may interfere with dogs' abilities to perform problem-solving tasks or to interpret information that could be useful in such tasks, including tasks involving or affected by noise. The extent to which noise reactivity or phobia is related to auditory dysfunction or impairment is not known. In this study, we asked whether known noise reactivity in dogs was reflected in any of several measures of auditory function: the brainstem auditory-evoked response, auditory middle-latency response, and mismatch negativity. Most noise-reactive dogs in this study were mildly affected (mean anxiety intensity rank [noise] score 17.65, maximum = 64). Comparison of the major auditory measures of dogs who were noise reactive with those of dogs who were non–noise reactive revealed a significant difference in only one variable of the brainstem auditory-evoked response test, right ear wave-V (RE-V) (Welch's t = 2.55, df = 22.41, P < 0.02). Auditory middle- and late-latency responses were present in all dogs that allowed for the completion of this test, providing initial evidence of higher order auditory-cognitive function. Behaviorally, the group of noise-reactive dogs was significantly different from the group of non–noise-reactive dogs with respect to their ability to undergo this testing: 5 of the 17 noise-reactive dogs were too reactive to undergo or complete the test but none of the 14 non-noise dogs were unable to undergo and complete testing. This study suggests that the underlying pathology resulting in noise reactivity may not influence auditory middle-latency response or mismatch negativity related variables, but the study should be expanded to a larger and more severely affected population of dogs.

Food-specific serum IgE and IgG reactivity in dogs with and without skin disease: lack of correlation between laboratories.

Despite conflicting data on their utility and no reports on interlaboratory reproducibility, serum food-specific antibodies are commonly assayed in first-opinion canine practice. To determine both the variability of test results between two laboratories and the frequencies and magnitudes of food reactivity in dogs of different disease status. Sera were obtained from eight dogs with cutaneous adverse food reaction (Group A), 22 with nonfood-induced atopic dermatitis (Group B), 30 with an allergic/inflammatory phenotype (Group C), 12 with miscellaneous skin diseases (Group D) and nine healthy dogs (Group E). Paired sera were submitted to two laboratories (A and B) for assays of food-specific IgE and IgG antibodies. Numbers of positive IgE and IgG tests determined by each laboratory in Groups A, B, D and E were comparable (GroupC not included). Significant differences in the magnitude of IgE reactivity between groups for each allergen were seen only for lamb (LaboratoryA, P=0.003); lamb reactivity in GroupD exceeded GroupE (P=0.004) but was comparable between all other groups. Agreement (kappa statistic) between the two laboratories' tests was 'moderate' for one antigen (potato IgE), 'fair' for four (corn IgE, rice IgE and IgG and soya bean IgG), 'slight' for eight (six IgE and two IgG) and 'less than chance' for the remaining six antigens (three IgE and three IgG). These laboratories' tests appear to have dubious predictive clinical utility because they neither correlate nor distinguish between dogs of different disease status.

Reactivity of dogs' brain oscillations to visual stimuli measured with non-invasive electroencephalography.

Studying cognition of domestic dogs has gone through a renaissance within the last decades. However, although the behavioral studies of dogs are beginning to be common in the field of animal cognition, the neural events underlying cognition remain unknown. Here, we employed a non-invasive electroencephalography, with adhesive electrodes attached to the top of the skin, to measure brain activity of from 8 domestic dogs (Canis familiaris) while they stayed still to observe photos of dog and human faces. Spontaneous oscillatory activity of the dogs, peaking in the sensors over the parieto-occipital cortex, was suppressed statistically significantly during visual task compared with resting activity at the frequency of 15–30 Hz. Moreover, a stimulus-induced low-frequency (∼2–6 Hz) suppression locked to the stimulus onset was evident at the frontal sensors, possibly reflecting a motor rhythm guiding the exploratory eye movements. The results suggest task-related reactivity of the macroscopic oscillatory activity in the dog brain. To our knowledge, the study is the first to reveal non-invasively measured reactivity of brain electrophysiological oscillations in healthy dogs, and it has been based purely on positive operant conditional training, without the need for movement restriction or medication.

TLR-2 but not TLR-9 is up-regulated in the Central Nervous System and Lymphoid Organs during Canine Visceral Leishmaniasis.

TLR-2 but not TLR-9 is up-regulated in the Central Nervous System and Lymphoid Organs during Canine Visceral Leishmaniasis.

Glial reactivity in dogs with visceral leishmaniasis: correlation with T lymphocyte infiltration and with cerebrospinal fluid anti-Leishmania antibody titres

Visceral leishmaniasis is a multisystemic zoonotic disease that can manifest with several symptoms, including neurological disorders. Because glial cells are extensively associated with the immune response within the brain, we evaluated the morphology of astrocytes and microglia of dogs naturally infected with Leishmania chagasi. We used immunohistochemical and lectin-histochemical techniques for morphological analyses and we also examined the glial correlation with lymphocyte infiltration of the brain and with the presence of anti-Leishmania antibodies within the cerebrospinal fluid of the dogs. Although we did not detect a shared morphological pattern in the astrocytes or microglia in the brain tissue, these cells were more intensely labelled in infected dogs than in the control group. The density of microglia was increased in the ependymal/subependymal area, thus demonstrating a strong correlation with the presence of T lymphocytes and with cerebrospinal fluid antibody titres. Thus, our results indicate a pro-inflammatory state in the brains of dogs naturally infected with L. chagasi and strongly suggest that microglia and astrocytes are involved in the pathogenesis of the neurological disorders of visceral leishmaniasis in dogs.

Pattern of Coombs’ test reactivity has diagnostic significance in dogs with immune‐mediated haemolytic anaemia

To investigate the clinical significance of the pattern of Coombs' test reactivity in dogs with immune-mediated haemolytic anaemia. Sixty-five anaemic dogs with a positive Coombs' test were included. Coombs' testing was performed at 4 and 37 degrees C with polyvalent canine Coombs' reagent and antisera specific for each of canine immunoglobulin G, immunoglobulin M and complement factor C3. The impact of performing testing with only polyvalent antiserum at 37 degrees C was assessed. Chi-squared tests were used to compare Coombs' test reactivity in dogs with primary immune-mediated haemolytic anaemia (group A) and in dogs with concurrent/underlying disease (group B). Following Bonferroni correction, significance was set at P < or = 0.003. Eleven dogs would have been regarded as Coombs' negative had they been tested with polyvalent antiserum at 37 degrees C alone. Group A dogs were significantly more likely to be positive with polyvalent antiserum and/or anti-dog immunoglobulin G at 4 and/or 37 degrees C (P < or = 0.001) and tended to be less likely to be positive with anti-dog immunoglobulin M at 4 degrees C (P=0.040). Testing of anaemic dogs with polyvalent Coombs' reagent at 37 degrees C was less sensitive than testing with monovalent reagents at 4 and 37 degrees C. The pattern of Coombs' test reactivity differed significantly between dogs with primary immune-mediated haemolytic anaemia and those with concurrent/underlying disease.

Immediate intradermal flea‐antigen reactivity in dogs in a flea‐scarce environment

The aim of this study was to determine the prevalence of intradermal test (IDT) reactions to flea antigen in dogs in a flea‐scarce environment. Seventy‐three client‐owned dogs without present or prior exposure to fleas were used. Forty dogs had a history of, and clinical signs compatible with, atopic dermatitis (AD), after exclusion of other causes of pruritus, and 33 dogs were healthy or had some disease other than AD. A questionnaire was used to collect information about previous ectoparasitic infestations. An aqueous extract of whole bodies of Ctenocephalides spp. (Nelco Laboratories Inc., NY, USA) was used for IDT at a concentration of 1:1000 w/v. None of the dogs had been treated with corticosteroids or antihistamines within the previous 3 months. A positive reaction was defined as a wheal that was equal to or larger in diameter than the average of the saline and histamine controls. Two of the dogs with clinically diagnosed AD and none of the nonatopic dogs had immediate skin‐test reactions to flea antigen. The prevalence (2.7%) for positive IDT against flea extract found in this study is low compared with studies performed in a flea‐rich environment. Immediate skin‐test reactivity against flea antigen in clinically normal dogs in flea‐endemic areas could represent subclinical hypersensitivity or true false‐positive reactions (due to skin irritation). Thus, these findings indicate that false‐positive reactions against whole‐body flea antigen from Nelco in dogs not exposed to fleas are rare.

Cerebral oxygen reactivity in the dog

Brain tissue oxygen reactivity is a measure of the increase in tissue oxygen pressure (PtO2) relative to an increase in arterial oxygen pressure (PtO2). Clinical studies show that PtO2 reactivity is increased after cerebral injury. However, the impact of patient ventilation on these measures is not known. We determined whether changes in end tidal carbon dioxide pressure (ETCO2) would affect PtO2 reactivity in dogs. After a craniotomy, a Neurotrend probe that measures PtO2 was inserted into the cerebral cortex of eight dogs. PtO2 reactivity was measured at five concentrations of inspired oxygen (room air, 40%, 60%, 80%, 95%) at three levels of ETCO2 (20 mmHg, 40 mmHg, 60 mmHg) in random order. PtO2 reactivity at ETCO2 of 20 mmHg was 0.2 and increased to 0.3 when ETCO2 was 40 mmHg and 0.4 when ETCO2 was 60 mmHg (p < 0.05). These results show that PtO2 reactivity increases from hypocapnia to normocapnia. It is important to consider the ventilation state of each patient when evaluating PtO2. Neurol Res 2000; 22: 620-622]

Effects of high thoracic epidural anaesthesia on the peripheral airway reactivity in dogs

It has been speculated that epidural anaesthesia may induce bronchoconstriction via the mechanism of a sympathetic blockade. However, this hypothesis has not been confirmed by any experimental evidence. Therefore, we investigated the effects of high thoracic epidural anaesthesia with neural sympathetic blockade on basal airway resistance and airway reactivity in response to bronchoconstrictive stimuli in a canine periphery lung model. Acetylcholine (Ach, 8 microg kg[-1] i.v.) or histamine (His, 3 microg kg[-1] i.v.) was administered to 7 anaesthetized mongrel dogs before and after thoracic epidural anaesthesia. Successful neuronal sympathectomy was confirmed by nitroglycerin test. The changes of peripheral airway resistance (Rp), haemodynamics, cardiac output (CO), and the recovery time for Rp from peak returning to baseline in each challenge were studied. Thoracic epidural anaesthesia altered neither the baseline Rp nor the peak Rp evoked by Ach or His. However, the recovery time of the Rp was prolonged significantly after epidural anaesthesia (P<0.01) and correlated inversely with the CO in response to Ach or His challenge (Ach, r=0.542; His, r=0.651). Our results suggest that epidural anaesthesia with neural sympathetic blockade has no influence on the basal peripheral airway resistance; however, it prolongs the airway reactivity to Ach or His challenge, probably by the mechanism of reducing CO.

Evaluation of association of blood and bronchoalveolar eosinophil numbers and serum total immunoglobulin E concentration with the expression of nonspecific airway reactivity in dogs

Abstract Objective To characterize the relation between bronchoalveolar and blood eosinophil numbers, serum total IgE concentration, and nonspecific airway reactivity in healthy dogs. Animals 26 healthy Beagles. Procedure Prior to measurement of nonspecific airway responsiveness, dogs were anesthetized and bronchoscopy was performed to recover bronchoalveolar lavage (BAL) fluid. Repeated measurements were made in 6 dogs. Results The percentage of blood eosinophils varied between 0 and 13 (mean ± SD, 5.6 ± 3.6) %, the percentage of eosinophils in BAL fluid ranged between 0 and 63.5 (8.8 ± 12.9) %, and total serum IgE concentration was 0.1 to 107.5 (23.4 ± 29.1) U/ml. A strong association was evident between numbers of blood eosinophils and total serum IgE concentration (R2 = 0.413, P &lt; 0.001), and a trend toward an association between numbers of blood eosinophils and numbers of eosinophils in BAL fluid was apparent (R2 = 0.110, P = 0.053). Significant associations were not found between any other aspects of the blood and BAL fluid cell profiles and total serum IgE concentration or airway reactivity. Serum total IgE concentration was not associated with airway reactivity. Further, in dogs examined on repeated occasions, variation in BAL fluid eosinophil numbers was not associated with any change in serum total IgE concentration or airway reactivity. Conclusions Neither numbers of bronchoalveolar or blood eosinophils nor serum total IgE concentration have a significant role in determining airway reactivity in healthy dogs. (Am J Vet Res 1997;58:34–39)

Reactivity of dogs and cats to feeding fleas and to flea antigens injected intradermally.

Reactivity of dogs and cats to feeding fleas and to flea antigens injected intradermally.

Effect of inflammation on peripheral airway reactivity in dogs

1. Eight mongrel dogs were studied to evaluate the effect of local inflammation on the response of collateral airways to histamine. In each dog we measured the baseline collateral resistance and its response to increasing doses of nebulized histamine. These measurements were obtained at weekly intervals, twice under control conditions and in three subsequent weeks after a local instillation of the bacteria Bordetella bronchiseptica. On each study day, after the measurements of collateral resistance, we lavaged the studied lung segment by instilling and aspirating 100 ml of saline (four 25 ml aliquots). All studies were performed in the same lung segment. 2. Collateral resistance remained stable under control conditions at 19.5 +/- 7.2 and 11.7 +/- 3.2 cmH2O l-1 min. With a bacteria-induced, mostly neutrophilic, inflammation, collateral resistance initially increased to 70.2 +/- 18.6 cmH2O l-1 min after 1 week and subsequently decreased towards control values (47.3 +/- 13 and 30.7 +/- 10.1 cmH2O l-1 min at 21 and 29 days, respectively). Collateral pathways reactivity, expressed as the slope of the relationship collateral resistance/log (1 + [histamine]), remained unchanged throughout the study. The values of this slope were (mean +/- SEM) 0.021 +/- 0.003 and 0.022 +/- 0.004 in the two control studies and 0.025 +/- 0.004, 0.030 +/- 0.006 and 0.023 +/- 0.003 in the three subsequent weekly studies. Inflammation, evaluated by the number of bronchoalveolar lavage cells and the percentage of neutrophils in bronchoalveolar cells, closely paralleled baseline collateral resistance with a peak value at the first week after the infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Attenuated vascular reactivity in dogs with anteroventral third ventricle lesions.

Lesion of the anteroventral portion of the third cerebral ventricle causes hypernatremia, adipsia, and attenuation of the pressor response to intravenous administration of angiotensin II and norepinephrine. In addition, these lesions prevent the development of several experimental models of hypertension. In this study, a lesion of the third cerebral ventricle region was made in 14 dogs. In seven dogs in which hypernatremia developed the lesions included the organum vasculosum of the lamina terminalis; seven animals in which the circumventricular organ was spared by the lesion remained normonatremic. Vascular responsiveness of isolated right carotid artery rings to angiotensin II and phenylephrine was assessed 3 days after lesioning the anteroventral portion of the third cerebral ventricle. In endothelium-denuded ring vessels, vasoconstrictor responses to phenylephrine were significantly decreased in animals both with and without inclusion of the organum vasculosum of the lamina terminalis. A similar effect was observed in intact vessels of dogs in which the circumventricular organ was spared but not in those with lesions that included this area. In contrast, angiotensin II-induced vasoconstriction was significantly decreased in the arteries with intact endothelium of both groups of lesioned animals. These data show that lesion of the anteroventral third ventricle area alters alpha 1-adrenergic and angiotensin II vascular responsiveness in isolated carotid artery rings with the possible participation of the endothelium.