Eighteen male English Pointers (2–4 years of age, 23:94 0:54kg body weight) were allotted to three diet and two physical conditioning groups to evaluate the effect of level and source of dietary fat on the olfactory acuity of canine athletes subjected to treadmill exercise. Diet groups (6 dogs/diet) consisted of commercially prepared diets (minimum of 26% crude protein) containing 12% fat as beef tallow (A), 16% fat provided by equivalent amounts of beef tallow and corn oil (B), or 16% fat provided by equivalent amounts of beef tallow and coconut oil (C). This dietary formulation resulted in approximately 60% of the total fatty acid being saturated for diets A and C, while approximately 72% of the total fatty acids were unsaturated in diet B. One-half of the dogs within each dietary groupwere subjected to treadmill exercise 3 times per week for 30 min (8.05 km/h, 0% grade) for 12 weeks. All
dogs were subjected to a submaximal exercise stress test (8.05 km/h, 10% slope for 60 min) every four weeks beginning at week 0. Olfactory acuity was measured utilizing behavioral olfactometry before and after each physical stress test. Non-conditioned (NON) dogs displayed a greater decrease (P < 0:05) in olfactory acuity following exercise, while physically conditioned (EXE) dogs did not show a change from pre-test values. A diet by treatment interaction (P < 0:10) was detected over the course of the study. NON dogs fed coconut oil had decreased odorant-detecting capabilities when week 4 values were compared with week 12 values. Feeding a diet that is predominately high in saturated fat may affect the odorant-detecting capabilities of working dogs. Additionally, these data indicate that utilization of a moderate physical conditioning program can assist canine athletes in maintaining olfactory acuity
during periods of intense exercise.
 
Altom et al. 2003
 
The unpredictability of epileptic seizures is considered an important threat to the quality of life of a
person with epilepsy. Currently, however, there are no tools for seizure prediction that can be applied to the domestic setting. Although the information about seizure-alert dogs – dogs that display changes in behavior before a seizure that are interpreted by the owner as an alert – is mostly anecdotal; living with an alerting dog (AD) has been reported to improve quality of life of the owner by reducing the stress originating from the unpredictability of epileptic seizures and, sometimes, diminishing the seizure frequency. Aim of the study: The aim of the study was to investigate, at an international level, the behaviors displayed by trained and untrained dogs that are able to anticipate seizures and to identify patient- and dog-related factors associated with the presence or absence of alerting behavior. Methodology: An online questionnaire for dog owners with seizures was designed. Information about the participants (demographics, seizure type, presence of preictal symptoms) and their dogs (demographics, behavior around the time of seizures) was collected. In addition, two validated scales were included to measure the human–dog relationship (Monash Dog–Owner Relationship scale (MDORS)) and five different traits of the dogs' personality (Monash Canine Personality Questionnaire refined (MCPQ-R)).
 
Martinez-Caja et al. 2019
 

In this work, a chromatographic method for identification of volatile organic compounds was compared with canine recognition. Gas chromatography and mass spectrometry (GC–TOF MS) were used for determination on concentrations of trace gases present in human breath. The technique enables rapid determination of compounds in human breath, at the parts per billion level. Linear correlations were from 0.83–234.05 ppb, the limit of detection was the range 0.31–0.75 ppb, and precision, expressed as relative standard deviation (RSD), was less than 10.00 %. Moreover, trained dogs are able to discriminate breath samples of patients with diagnosed cancer. We found a positive correlation between dog indications and the ethyl acetate and 2-pentanone content of breath (r00.85 and r00.97, respectively). The methods presented for detection of lung cancer markers in exhaled air could be used as a potential non-invasive tool for screening. In addition, the canine method is relatively simple and inexpensive in comparison with chromatography.

Buszewski et al. 2012

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Effects of steroids on the olfactory function of the dog. PHYSIOL BEHAV 51(6), 1183-1187, 1992.--Twenty-four (24) mature, mixed breed, healthy dogs weighing from 14.6 kg to 27.6 kg were used to study the effects of various steroids on the olfactory function of the dog using olfactory detection threshold as an index. Two odorants were used, viz; benzaldehyde and eugenol. Of the various steroids used, only dexamethasone produced classical signs of Cushing's syndrome in the dogs. However, all dogs that received either dexamethasone alone or hydrocortisone plus DOCA exhibited a significant elevation in the olfactory detection threshold for both odorants without any observable structural alteration of the olfactory tissue using light microscopy. On the other hand, neither DOCA, hydrocortisone alone, nor any of the vehicles used in the study significantly altered the olfactory function of the dogs. The results show that Cushing's syndrome can be  experimentally produced in dogs using exogenous steroids and that this condition diminishes the olfactory capability of the dog without producing classical signs of the disease.

Ezeh et al. 1991

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Experimental studies using trained dogs to identify breath odour markers of human cancer, published in the recent decade, have been analyzed and compared with the authors’ own results. Particular published studies differ as regards the experimental setup, kind of odour samples (breath, urine, tumor tissue, serum), sample collection methods, dogs’ characteristics and dog training methods as well as in results presented in terms of detection sensitivity and specificity. Generally it can be stated that trained dogs are able to distinguish breath odour samples typical for patients with lung cancer and other cancers from samples typical for healthy humans at a ‘better than by chance’rate. Dogs’ indications were positively correlated with content of 2-pentanone and ethyl acetate (r = 0.97 and r = 0.85 respectively) and negatively correlated with 1-propanol and propanal in breath samples (r = −0.98 and −0.87 respectively). The canine method has some advantages as a potential cancer-screening method, due to its non-invasiveness, simplicity of odour sampling an storage, ease of testing and interpretation of results and relatively low costs. Disadvantages and limitations of this method are related to the fact that it is still not known exactly to which chemical compounds and/or their combinations the dogs react. So far it could not be confirmed that dogs are able to sniff out early preclinical cancer stages with approximately the same accuracy as already diagnosed cases. The detection accuracy may vary due to failure in conditioning of dogs, decreasing motivation or confounding factors. The dogs’ performance should be systematically checked in rigorous double-blind procedures. Recommendations for methodological standardization have been proposed.

Jezierski et al. 2015

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It has long been known that odors and olfaction play a major role in behavioral development and expression in animals. The sense of smell is employed in numerous contexts, such as foraging, mate choice, and predation risk assessment. Indeed, olfaction is the primary sensory modality for most mammals, and many domestic species kept by humans, including chickens (1). Odors are therefore likely to influence many of the handling and management procedures carried out with animals, whether on farms, in zoos, in the laboratory, or in the family home. Despite this, applied ethologists and animal welfare scientists have not to any great extent investigated chemosensory perception or included odors in their studies.

Nielsen et al. 2015

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Despite the large and growing dependence on dog-handler teams for solving ‘‘real world’’problems of odor detection, recognition and localization, no comprehensive methodology for quantifying the capabilities of such teams has been reported. We developed an approach in which each dog is housed with its owner-handler, deprived of neither food nor water and indicates to its handler which of five Teflon boxes contains the target odorant of n-amyl acetate (nAA). In two dogs (Rottweiler, Standard Schnauzer) trained in this way, precisely controlled concentration ranges of nAAwere systematically lowered over the course of several weeks, in blocks of three 9-trial sessions, until chance performance was seen. Data for each concentration were expressed in terms of a logistic regression equation relating concentration to the binomial probability that the observed performance (or better) would be seen by chance alone. That concentration corresponding to a probability of 0.05 was defined as threshold. In this admittedly small sample, the values we obtained (1.9 and 1.14 ppt) are roughly 30- to 20,000-fold lower than the range of thresholds reported by Krestel et al. [Krestel, D., Passe, D., Smith, J.C., Jonsson, L., 1984. Behavioral determination of olfactory thresholds to amyl acetate in dogs. Neurosci. Biobehav. Rev. 8, 169–174] in their conditioned suppression study of beagle sensitivity to nAA. Thus, it appears that there are significant advantages to our approach, though the reasons for differences in results are unclear. The ‘‘find the target’’ aspect of this new method makes it readily applicable to odor processing tasks much more complex than detection of single compounds.

Walker et al. 2006

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