Browsing by Author "Hall, Nathaniel J."
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Item A novel method for the creation of canine explosive detection training aids using an olfactometer(2018-12) Nguyen, Thy; Prada, Paola A.; Hall, Nathaniel J.; Sperry, KathyThe prevalence of terrorism around the globe has made explosive detector dogs an invaluable tool for homeland security, creating a need for reliable training aids for optimal performance results. While research exploring the use of other animals such as rats, wasps, honey bees, and moths as explosive detectors have been done, canines remain the preferred method of detection. The use of an olfactometer in olfaction-based research is the key to understanding complex odor mixtures. This instrument is used to not only detect and measure odors but also to investigate and understand odor dilutions. One of the benefits that arise from using an olfactometer to create training aids for canines will be the ability of these training aids to expose the canines to the actual odor of the explosive source that the canine is expected to detect without posing a safety or handling risk to either the dog or the handler. The creation of explosive training aids using an olfactometer also opens the door to rapidly and optimally generating training aids from new homemade explosive devices. This could mean that military and law enforcement personnel could collect explosive residue from the field and allow the analyst to create a training aid that simulates current threats. This thesis experiment was conducted with the intent of evaluating the potential of training aids using commercially available smokeless powders, sugar, and a laboratory made olfactometer, specifically designed to investigate various experimental parameters for use in training dogs in explosives detection. By evaluating if training aids created using an olfactometer have a detectable odor signature for use and discovering the longevity of these new training aids, this thesis experiment hopes to open up a new avenue for canine training aid manufacture to be used throughout the United States for national defense at home and abroad.Item An Automated Canine Line-Up for Detection Dog Research(2021) Aviles-Rosa, Edgar O.; Gallegos, Shawna F.; Prada-Tiedemann, Paola A.; Hall, Nathaniel J.Currently, there is a need to develop technology that facilitates and improves detection dog research. The aim of this research was to develop an automated computer-driven olfactory line-up task. The apparatus consisted of three olfactometers. Each olfactometer was equipped with flow meters to regulate air flow and dilution and six solenoid valves connected to odor jars. Each olfactometer generated an odor which was carried to an odor port where the dogs sample it. The olfactometer's valves were activated by a microcontroller, and a Python program was built to control each olfactometer and randomize and balance the odor presentation. Dogs (N = 12) received one or two 40-trial training sessions in a day where they progressed through a series of training phases where they learned to detect and alert to double-base smokeless powder (SP). An “alert” consisted of a 4-s nose hold. This was measured by infrared sensors in the ports. For each trial, the apparatus recorded dogs' search latency, sniff time, port entries, and response. All this information was automatically recorded in a csv file. A photoionization detector (PID) and solid-phase microextraction followed by gas chromatography-mass spectrometry (SPME-GC/MS) were used to evaluate the odor dynamics and to instrumentally verify odor presence and clearance. A control test was conducted at the end of the training to ensure dogs were alerting exclusively to the odorant. All 12 dogs readily learned to operate the apparatus within 23 days, and all exceeded 85% accuracy. Control tests indicated dogs were leveraging only olfactory cues and not unintentional cues such as auditory cues from the apparatus. Analytical data showed that odor was detected in the port immediately after the activation of a valve and that odor clearance occurred immediately after the valve was closed. The apparatus developed was easy to operate by the dogs and allowed substantial data collection using double-blind testing procedures in a very short period at an affordable cost point for research equipment (~$5,000 USD). The apparatus may prove to be a useful research tool to provide optimal odor stimuli control, ensure double-blind conditions, reduce labor, and significantly increase the amount of data collected.Item Behavioral, physiological, and neurological influences of pheromones and interomones in domestic dogs(2018-05) Pirner, Glenna M; McGlone, John J.; Garcia, Arlene; Hall, Nathaniel J.; Protopopova, Alexandra; Mechref, YehiaPheromones provide a crucial method of information transfer for many species; however, this type of communication is not well understood in the domestic dog. Beyond intraspecific communication, evidence suggests that some molecules, known as interomones, may act as a pheromone in one species but elicit unpredictable effects in a different species. 2-methylbut-2-enal (2M2B), the rabbit maternal-neonatal pheromone, is one such molecule. To determine the behavioral and physiological effects of 2M2B on chronically stressed domestic dogs two stress-induction models were used: a simulated thunderstorm and car travel. In both models, 2M2B elicited a faster return of elevated heart rate (HR) to baseline compared to control (CON). During the thunderstorm dogs treated with 2M2B spent 15.9% more time lying down compared to when treated with CON (p = 0.04). Heart rate variability measures, leukocyte differentials, and adrenocorticotropic hormone-stimulation tests were recorded from the dogs used in these studies to understand how acute stressors affect chronically stressed dogs, and how 2M2B might ameliorate this response. Average R-R interval was negatively, but not significantly, correlated with the magnitude of difference in heart rate between placebo and 2M2B ointment during the simulated thunderstorm. There is limited research on domestic dog pheromones, and there are notable inconsistencies in the literature that does exist. To identify urinary volatiles that may act as pheromones, urine was collected from five individuals in each of six groups: juvenile intact male (JIM), adult intact male (AIM), adult castrated male (AXM), juvenile intact female (JIF), adult intact female (AIF), and adult ovariohysterectomized female (AXF). Headspace sampling yielded six molecules with significantly different peak areas between groups. Octanal, 2-methyl-quinoline, methyl propyl sulfide, and 2-heptanone appear to be closely linked to male sex hormones as they had significantly higher peak areas in intact adult males. 3-ethylcyclopentanone appears to be associated with intact adult females and castrated or subordinate male animals. No sex or life stage patterns could be divulged from the data on 2-pentanone. For a molecule to elicit a behavioral or physiological response, it stands to reason that regions of the brain corresponding to the effect should be activated. 5α-androst-16-en-3-one elicits behavioral and physiological effects in women, especially during the time of ovulation. Functional magnetic resonance imaging (fMRI) and blood-oxygen-level dependent (BOLD) contrast were employed to determine which areas of the brain might be responsible for these effects. Ten women received an fMRI scan with ANDRO, 2M2B, rose odor (ROSE), and fresh air (CON) in a 15 s on / 45 s off block design, with three randomized repetitions. ANDRO activated the left insular region compared to CON (p = 0.04). 2M2B elicited activation in the somatosensory association cortex (p < 0.01), premotor cortex (p < 0.01), and Brodmann’s area 8 (p = 0.03) compared to CON. 2M2B also elicited activation in the posterior cingulate and angular gyri compared to ROSE (p < 0.01, both). The insula and amygdala are regions associated with olfactory processing and so were expected. 2M2B elicited activation mainly in motor processing regions, suggesting a motor response to the molecule. Evidence that either molecule activated the hypothalamus, as would be expected by a priming pheromone, was not observed.Item Canine threshold to double base smokeless powder(2021-08) Sanford, Madelyn; Hall, Nathaniel J.; Schroeder, Katy; Tiedemann, PaolaCanines have been employed to thoroughly search susceptible areas such as schools, sporting events, concerts, and more for explosives and other weapons. Unfortunately, while dogs are so readily utilized, little is known about dogs’ detection limits to essential odorants. This study aimed to determine eleven dogs' thresholds to double-base smokeless powder utilizing an air dilution olfactometer to evaluate individual differences. Using a 2-up, 1-down adaptive descending staircase procedure, dogs completed two threshold assessments which were required to meet a specific repeatability criterion. More assessments were required if dogs did not meet our repeatability criterion. Using dog as a fixed effect in our linear model, we found that there were important differences in detection limits between individuals, with some dogs showing consistently lower thresholds and an overall variation of 1,100-fold difference between the best and worst threshold. The results from this study validated the use of an air dilution olfactometer with a correlation measure of 0.86. highlighted individual differences in detection dogs. In addition, the data highlighted individual differences in detection dogs, suggesting that some dogs are inherently better at detecting smokeless powder.Item Comparing demand and preference assessments for food products in dogs(2019-05) Wyant, Rachel L.; Hall, Nathaniel J.; Protopopova, Alexandra; McGlone, John J.Canine food preference is commonly measured using two-bowl and one-pan tests. These methods measure preference in a free-choice format. Free-choice, however, can be a poor measure of reward value. The aim of this study was to compare and contrast typical free-choice based methods of food preference to recently developed behavioral economic models of reward value to see how preference and reward value measures relate. Ten dogs were tested on a demand assessment and a preference assessment. Four food products were used, with the subjects tested first on the demand assessment, followed by a two-bowl device for the preference assessment. Dog responding in the demand assessment on a lever was evaluated on a fixed ratio schedule (FR 1, FR 2, FR 5, FR 10, FR 20). Comparing the results of the demand assessment to the preference assessment, the dogs’ preferences are more clearly defined in the latter. The preference assessment identified differences both across food category and within category, the value of the products, as measured by demand, revealed only differences in product type, but not statistically significant differences within type. Measuring canine food preferences is important for measuring flavor and palatability. Not only is it important for the pet food industry, this information is valuable in identifying appropriate reinforcers for training. The applications of this study could have benefits for both pet food companies and trainers.Item Effect of direct-fed microbial supplementation on dietary nutrient digestibility and fecal characteristics of dogs(2019-08) Soto, Stephanie; Hall, Nathaniel J.; Sarturi, Jhones; Protopopova, Alexandra; Schroeder, KatyThe nutritional composition of a diet influences gut microflora, which in turn influences digestion of food and absorption of nutrients. Direct-fed microbes are often supplemented in the diet to improve the health of animals; however, the effect of direct-fed microbial supplementation on nutrient digestibility and fecal characteristics in dogs, as well as how it affects palatability, is not well known. The objective of this study was to determine the effect of a direct-fed microbial supplementation in dogs on the following characteristics: dry matter, organic matter, apparent total tract nutrient and energy digestibility, fecal pH, and fecal score. Twelve dogs, fed a premium commercial diet, were divided into two groups which were randomly assigned the following treatments: a) Control (no Direct Fed Microbes [DFM]), and b) DFM (Bacillus subtilis (2×109 CFU/g), Bifidobacterium bifidum (2×109 CFU/g), Enterococcus faecium (4×109 CFU/g), Lactobacillus acidophilus (3×109 CFU/g), and Lactobacillus casei (4×109 CFU/g). Dogs underwent their assigned treatment for 33 days. Overall, the supplementation of the direct-fed microbes did not affect dry matter, organic matter, or gross energy digestibility, as well as fecal scores or fecal pH. Our results did show a clear food preference for the food with the direct-fed microbes. These results highlight that the DFM had a positive impact on palatability, but in our sample of healthy dogs fed a high-quality diet, enhancements in digestibility were not evident.Item Effect of handler knowledge of the detection task on canine search behavior and performance(2020) DeChant, Mallory T.; Ford, Cameron; Hall, Nathaniel J.Detection dogs are commonly trained and tested under conditions in which the handler or the evaluator knows the true presence or absence of a target odor. Previous research has demonstrated that when handlers are deceived and led to believe that a target odor is present, more false alerts occur. However, many detection teams operate under unknown conditions, and it remains unclear how handler knowledge (or lack thereof) of odor presence/absence influences the dog's behavior. The aim of this study was to evaluate if knowing the number of hides placed influenced detection dog performance in an applied search environment. Professional (n = 20) and sport (n = 39) detection handler-dog teams were asked to search three separate areas (area 1 had one hide, area 2 had one hide, area 3 was blank). Handlers in the Unknown Group were not told any information on the number of hides whereas the Known Group were told there was a total of two hides in the three areas. The sport Unknown Group spent a longer duration (69.04 s) searching in area 3 compared to the sport Known Group (p = 0.004). Further, sport dogs in the Unknown group looked back to the handler more frequently. When a miss did occur, dogs of both sport and professional handlers showed an increase interest in the location of the target odor compared to a comparison location. Critically, however, there was no difference in false alerts between the Known Group and Unknown Group for sport or professional handlers. In a second experiment, fourteen professional, and thirty-nine sport teams from Experiment 1 conducted an additional search double-blind and an additional search single-blind. Both sport and professional-handler dog teams had statistically similar accuracy rate under single and double blind conditions. Overall, when handlers knew the number of hides, it led to significant changes in search behavior of the detection team but did not influence the overall false alert rates.Item Effects of additional walks and social play on physical activity and rest in shelter(2020-05) Cordova, Eduardo; Hall, Nathaniel J.; McGlone, John J.; Machado, Eila; Protopopova, AlexandraDogs entering the shelter experience stress upon admission and throughout their time in the shelter. Different enrichment interventions have been used to mitigate the adverse effects of stress and promote physical and psychological well-being of these dogs. The objective of the current study was to evaluate two enrichment strategies, walk and social play, and identify differences in physical activity and rest during and after enrichment sessions. To evaluate walks and social play, twenty-five shelter dogs housed at two locations were tested in a within-subject design. Dogs wore accelerometers (Whistle Activity MonitorTM) for 16 days. Analysis of in-kennel rest and physical activity revealed that, on average, dogs at the Canine Olfaction Research and Education (CORE) lab received significantly more physical activity from an additional walk than an additional play session (est.=0.86, z=9.8, P<0.001). There was no significant difference between each event for The Shelter dogs (est.=0.08, z=1.01, P=0.31). Moreover, dogs from the CORE lab had more in-kennel rest than dogs at the Shelter (est.=0.21, z=4.04, P<0.001), and rested more during daylight active times (est.=0.83, t=2.6, P=0.016). On average, dogs across both locations rested more during days in which they received an additional walk (est.=0.021, z=6.2, P<0.001; est.=0.026, z=8.98, P<0.001). There were individual differences observed between dog pairs, both in physical activity and rest. Physical activity and rest may be useful measures of welfare in shelter dogs, but these two factors may not be directly related. Differences in physical activity and rest between locations and individuals indicates the dog’s social partner during sessions. there may be several factors that cumulatively influence whether a dog receives more physical activity from a walk or play session with a companion. Moreover, there may be several factors that influence the amount of rest a dog receives.Item Effects of various nutritional supplements on the development, innate immunity, and gastrointestinal health of young dairy calves(2018-08) Liang, Yu; Ballou, Michael A.; Machado, Vinicius; Neves, Rafael; Neary, Joseph M.; Hall, Nathaniel J.The neonatal calves are extremely susceptible to enteric diseases during the first few weeks of life. According to the report form USDA, the mortality rate of newborn calves is about 10%; however, the death caused by enteric diseases accounts for 50% of mortality. On the other hand, antimicrobials are widely used in the dairy industry in the past decades; but the concern has been increased for using antibiotic in recent years. Therefore, there is more interesting to find alternatives to antibiotic use which has similar efficacy as antibiotic in decreasing diseases. Some studies have been conducted to investigate effects of those nutritional supplements on growth performance and health on swine and poultry industry. For current research, yeast cell wall, various strains of probiotic, egg protein, and hydrolyzed yeast will be investigated for effects on growth performance, innate immunity, and gastrointestinal development in young dairy calves. In first study, effects of Provia® (Bacillus coagulans 6086) and OmniGen AF® alone or in combination on growth performance, innate leukocyte responses, and enteric health of pre-weaned and immediate post-weaned dairy calves were evaluated. Treatments in this study were: CON: base milk replacer and calf starter; PV: 2 x 109 CFU/d of Bacillus coagulans 6086 in milk replaer and 2 x 109 CFU of Bacillus coagulans 6086 per kg of the base calf starter; OG: 12g/d of OmniGen-AF in milk replacer and 12 g of OmniGen-AF per kg of the base calf starter; OG+PV: supplement with both of the Bacillus coagulans 6086 and OmniGen-AF. The PV supplemented calves had greater ADG from d 71 to d 84 during post-weaning period. There were no treatment differences in the percentage of calves that scoured throughout the study. The results of this study indicated that neither Provia, Bacillus coagulans 6086 nor OmniGen-AF greatly influenced the growth performance or enteric health during the pre-weaned or immediate post-weaned periods. The impact of a blend of a strain of Lactobacillus casei and an Enterococcus faecium strain on physiological response to an oral Salmonella enterica serotype Typhimurium challenge in neonatal Jersey calves was investigated in second study. The treatments in this study were: CON: base milk replacer; CON+ST: base milk replacer with Salmonella typhimurium challenge on d 7; PRO+ST: base milk replaer with a blend of a strain of Lactobacillus casei and an Enterococcus faecium strain and challenged with Salmonella typhimurium on d 7. Serum haptoglobin and urea N concentrations were increased on d 10 in CON+ST comparing to PRO+ST. In contrast, PRO+ST had greater rectal temperature after challenge than CON+ST. Further, neutrophil percentages in PRO+ST were greater than CON+ST or CON. However, 7 of 8 calves in PRO+ST had elevated neutrophil percentages on d 10 relative to d 7, whereas 4 of 8 calves among the CON+ST had reduced neutrophil percentages on d 10 relative to d 7. The ratios of villi height to crypt depth in both of duodenum and ileum were greater in PRO+ST than CON+ST calves. These data indicated that supplementing neonatal calves with the blend of probiotics used in the current study improve the pathophysiological response and small intestinal health and development with an enteric Salmonella typhimurium challenge. The objective of final study is to determine the impacts of supplementing a blend of yeast culture, yeast extract, hydrolyzed yeast, and immunized egg antibodies on the growth performance and health of calves challenged with Salmonella typhimurium. There are 4 treatments in current study: CON: base milk replacer; CON+ST: base milk replacer with Salmonella typhimurium challenge on d 7; CA: milk replacer supplemented with 16 mL/d CalfAce; CA+ST: base milk replacer supplemented with 16 mL/d CalfAce and challenged with Salmonella typhimurium on d 7. The calves with challenge had decreased starter intakes. CalfAce supplementing calves decreased serum haptoglobin concentration. Calves supplemented with CalfAce had greater villi height to crypt depth ratio in duodenum when compared to non-supplemented calves. In conclusion, CalfAce supplementing calves reduced both of systemic and local inflammatory response and improved the gastrointestinal health.Item Enrichment strategies that modify cat behavioral pattern: Their applications in improving welfare(2019-05) Zhang, Lingna; McGlone, John J.; Protopopova, Alexandra; Hall, Nathaniel J.; Conover, William J.; Schmidt, Kenneth A.This dissertation aimed to identify effective environmental enrichment strategies for cats over both the short- and long-term. In study I, preferences of scratchers differing in shapes and covering materials were evaluated in adult household cats. Preference indexes (PI) calculated based on the frequency and duration of scratching and interactions were shown to be significantly higher with the standing cardboard scratcher compared to the laying S-shaped cardboard (N = 7 houses, P < 0.01). Standing scratchers covered with rope and cardboard received more scratching and interactions (N = 14 houses, P < 0.05) compared to scratchers covered with sofa fabric, and scratchers with carpet were intermediate. Standing scratchers covered with cardboard and rope are preferred scratching devices for adult cats. In study II, fecal and urinary samples were compared between adult intact male and female cats for volatiles using gas chromatography-mass spectrometry in order to identify sex-related semiochemicals that might attract cats. Males had higher concentrations of 3-Mercapto-3-Methyl Butanol (MMB, N = 7/sex, P < 0.001) in the urine and butanioc acid (N = 8 females, 10 males, P = 0.02) in the feces than females. Standing cardboard scratchers treated with the mixed solution of MMB and butanoic acid (i.e., estimated amount from one elimination) through hanging sock had aversive effects on the use of scratcher in cats (N = 28), as indicated by the significantly decreased scratching duration and frequency, as well as the interaction duration compared to the placebo scratchers. The male-representative mix of MMB and butanoic acid may reduce inappropriate scratching in cats. In study III, cat attractants such as catnip (CN) and silver vine (SV) that known to induce active responses in cats, were tested for their efficacies of modifying the use of scratchers. The feline interdigital semiochemicals (FIS) shown by other study to increase the scratching behavior in cats, was also included. Each treatment (i.e., CN, SV, and FIS) was delivered to a standing cardboard scratcher through a hung sock, which was compared to a control scratcher with an empty/placebo sock. Cats had access to both the control and treated scratcher at same time in each treatment group and cats from different households were exposed to all the three treatment groups in a randomized order. Both CN and SV significantly increased (P = 0.02) the interaction duration and frequency compared to control. Catnip also increased (P = 0.02) the scratching duration. The treatment of FIS only tended to increase the interaction frequency (P = 0.06). Catnip and silver vine are effective in increasing the use of scratchers in cats. In study IV, the effects of cardboard standing scratchers treated with CN and SV on activity and weight management were evaluated in household cats. Animals from the treatment group (N = 12) received the treated scratcher and were compared with cats on the control group (N = 4), which did not receive the scratcher over a 4-week period. Weekly activity levels recorded by PetPaceTM monitor collars and body weights were not significantly affected (P > 0.10) by time, treatment or time by treatment interaction. Cats on the treatment group habituated to the enrichment as scratching and interaction related measures decreased significantly over time (scratching duration and frequency, P = 0.002; interaction duration, P < 0.0001; interaction frequency, P = 0.0004). The long-term effects of enrichment on cat activity and body weight requires future study and obese cats in more controlled settings may serve as better subjects.Item Environmental Effects on Explosive Detection Threshold of Domestic Dogs(2023-05) Fernandez, Lauren; Hall, Nathaniel J.; Tiedemann, Paola; Stellato, AnastasiaDetection canines are deployed to detect explosives in a wide range of environmental conditions. These environmental conditions may have negative impacts on canine capabilities as a sensor. This study leveraged an air dilution olfactometer to present controlled odor concentrations of four different energetic materials (double base smokeless powder, C4, ammonium nitrate, and flake TNT) to dogs working in a range of high temperature, standard, and low temperature conditions with high and low humidity conditions. The air dilution olfactometer controlled concentrations independent of environmental condition and dogs’ detection threshold limits were measured using a descending staircase procedure. We measured dogs’ threshold twice for each energetic under each environmental condition. Results indicated heterogeneity in effects based on energetic, but all odors were detected at the lowest concentrations under standard conditions. Smokeless powder detection was reduced under all environmental conditions compared to standard and was least detectable under high temperature and humidity conditions. AN detection was poorest under high temperature both high and low humidity conditions. C4 in contrast, was least detectable at low temperatures with high humidity. TNT detection was difficult under all conditions, so decrements were not statistically detectable. Additional measures were also found to be associated with detection limits. Under high temperature conditions, correlations were observed between canine mean subcutaneous temperature and detection limits, such that dogs experiencing greater temperature increases showed poorer detection limits. In addition, dog’s latency to sample the odor port from the onset of a trial was longest in the high temperature conditions. Further, longer latencies were predictive of poorer detection limits. Overall, dogs showed deficits in detection sensitivity limits under all environmental conditions for at least one energetic material when the concentration of that energetic material was not directly impacted by the environmental conditions. These results suggest that behavioral factors related to environmental exposure can have important impacts on canine detection sensitivity and should be considered in operational environments.Item Evaluating volatile organic compounds from the spotted lanternfly (Lycorma delicatula) using headspace odor sampling methods(2023-05) Cantu, Ariela; Prada-Tiedemann, Paola A.; Cañas-Carrell, Jaclyn; Hall, Nathaniel J.The Spotted Lanternfly (SLF) is an invasive species native to China, and it was first discovered in the United States in Pennsylvania in 2014. It is known to cause great economic damage by destroying various crops, specifically grape vines, and therefore several efforts have been made to control and mitigate its spread from the Northeast. Detection of the invasive spotted lanternfly is key to reduce ecological impacts as well as to reduce expensive eradication costs. Canine detection is a useful detection tool in this pest detection effort, however, an important aspect to further eradication developments via canine means is to understand the odor chemistry of this target substrate. The purpose of this study was to address the gap in research regarding the volatile organic compound (VOC) profile of the SLF and provide more information on the chemical odor signature of SLF as well as other distractor odors, to better inform pest control mitigation strategies utilizing trap technologies and canine detection teams. Instrumental analysis was performed utilizing SPME-GC/MS on SLF eggs, crickets, and bark from its innate environment. The developed SPME-GC/MS method proved to be a valid and reliable approach for VOC analysis of target samples. Differences in shared compound abundance and other detected VOCs within each sample set depicted distinctive odor profiles for each matrix tested. The major conclusion that this study presented is that SLF eggs have a distinctive chemical odor profile comprised of the following compounds: Anisole, Tridecane, Dodecane, 2-Nonanone, 3-Octanone, and D-Limonene, as these were the most frequently seen in the various samples. The SLF egg and cricket samples did not share many compounds, which was in direct opposition to part of the hypothesis that SLF eggs would share compounds with other insects. The selected method proved that detection of odor volatiles even after 6-weeks of frozen storge suggests cold storage safeguards volatile detection, however, the VOC profile of the SLF eggs and crickets did not persist across the 6-week frozen study and did not equate to optimal volatile reproducibility. The VOC profile of the SLF eggs and crickets did not persist consistently across the 6-week dissipation study, and it was determined that the SLF egg vials should be left closed for VOC retention. While the crickets did not depict a statistically significant variation in VOC accumulation as a function of lid type, the detection of extraneous VOCs in the headspace does suggest a need for closed sampling handling for better integrity of the chemical odor profile.Item Evaluation of decomposition residual odor using Sus scrofa as a sampling model(2019-05) Raymer, Jennifer L.; Prada, Paola A.; Presley, Steven M.; Hall, Nathaniel J.This research project will impact the forensic field by providing an insightful scientific perspective on the chemical composition of decomposition odors of human analogues emitted into the environment. By studying the chemical makeup of decomposition odor or the “scent of death”, enhanced understanding of stage-specific volatile organic compounds (VOCs) can provide better understanding for better detection methods to be developed. This study also achieved a preliminary understanding of when a specific area can be cleared of any remaining decomposition odor. Not only will this study aid in the potential location of holding sites or transportation methods, it will also aid in optimal training of human remains detection dogs. There has been limited scientific research into how decomposition residual volatile organic compounds change over time, with even less scientific research into how the compounds change in a dry, arid environment such as west Texas. Emerging research has begun to look into the compounds present in soil during decomposition, but limited studies are specifically looking at the change of compounds as a longitudinal analysis over time, after the removal of the decomposing item. The purpose of this study was to monitor and provide abundances of the target decomposition odor vapors emanating from the soil after removal of decomposing human analogues (sus Scrofa). Pig meat samples and carcasses were placed in an outdoor study site to model the decomposition process and VOCs were collected intermittently over a one-month period. The odor collection process consisted of allowing pigs to decompose for a period of 14 days, 17 days and 21 days, then removing the pigs and sampling the soil once per week for a period of four weeks. Instrumental analysis utilized Divinylbenzene/Carbon/Polydimethylsiloxane (DVB/CAR/PDMS) coated Solid Phase-Microextraction (SPME) fibers that were injected into a Gas Chromatography-mass Spectrometry (GC-MS) system for the identification of extracted soil headspace odor profiles of target decomposition odors. The soil samples were sampled individually in 15mL glass vials for a period of 24 hours to allow for headspace extraction time optimization. Weather conditions such as temperature and humidity were recorded during each soil sample collection, as well as soil pH and moisture content. During each sample extraction, at each of the three intervals, both abundance and type of target volatiles were analyzed. The purpose was to document the change in both the type of volatiles present and their abundance at each of the set intervals. VOCs of interest were identified over the duration of the study, showing distinctive trends in compound abundance and disappearance. The benefit produced by the study has heightened the understanding of how decomposition odor changes over a set period of time. This research will ultimately aid in the knowledge and understanding of odor composition and concentration levels of residual decomposition odor for given decomposition times, with the generated information supporting search and recovery of holding sites and possible modes of transportation at various stages of decomposition.Item Intake Vaccinations Reduced Signs of Canine Respiratory Disease During an Outbreak at an Animal Shelter(2021) Andrukonis, Allison; Brown, Kelsea M.; Hall, Nathaniel J.; Protopopova, AlexandraAnimal shelters provide an ideal environment for the spread of disease. Dogs are often housed in close quarters with others of unknown vaccine histories, and experience high levels of sustained stress. As a result, Canine Infection Respiratory Disease (CIRD) is often prevalent and difficult to control. The aims of this study were to (1) identify specific pathogens responsible for CIRD in a city shelter in West Texas, USA, and (2) determine whether intake vaccinations decrease proportion of dogs exhibiting signs of CIRD even during an outbreak. A laboratory analysis of conjunctival, pharyngeal, and nasal swabs (n = 15 dogs) and fecal samples (n = 6 kennels) showed prevalence of various CIRD pathogens (e.g., canine adenovirus-2, canine parainfluenza virus, canine distemper virus). All fifteen dogs tested positive for at least one pathogen, with the most prevalent pathogen being Canine Distemper Virus (CDV; n = 12). All of the kennels (n=6) tested positive for Canine Distemper Virus. Health data on dogs (n = 1,258) over the age of 6 weeks were assessed from May to August 2017. Beginning in July, both stray and owner-surrendered dogs were vaccinated with Nobivac® Canine 1-DAPPv 5 Way and Nobivac® Intra-Trac® 3 upon intake, which differed from the previous policy. For each day in the study, we calculated the proportion of dogs in each nasal discharge category, the proportion of dogs observed coughing, and the mean fecal score across all dogs. We conducted a linear regression between the proportion of the shelter vaccinated and the proportion of dogs coughing. At the beginning of the vaccination phase, ~25% of the dogs were coughing. However, as the proportion of the dogs vaccinated increased, the proportion of dogs coughing decreased. There was a significant decrease of 7% of the proportion of dogs coughing when vaccination was at least at 90% compared to when it was <90%. These data suggest that the shelter in this study was experiencing a CIRD outbreak, with CDV being primary pathogen, and that it is possible to substantially reduce illness by implementing a vaccination on intake protocol. The current study provides support for the importance of vaccination in animal shelter welfare.Item Lactobacillus salivarius L28 in dog kibble results in shifts in microbial indicators in pet fecal samples after feeding(2018-08) Katawal, Ishwar; Brashears, Mindy M.; Echeverry, Alejandro; Miller, Markus F.; Hall, Nathaniel J.; Calle, AlexandraCertain probiotic lactic acid bacteria (LAB), also called Direct fed microbials (DFM), have beneficial effects in the gastrointestinal tract (GI) of pets through competitive exclusion of enteric-pathogen or by modulating the population of GI microflora, which can be monitored through the change in the load or shedding of microbial indicators such as: Generic E. coli, fecal coliforms, Entereobacteriaceae and Salmonella in fecal samples. Additionally, changes in the microbial populations can improve the overall gut health of the animal. The purpose of this study was to evaluate the impact of various combinations of probiotics including Lactobacillus salivarius L28 in the indicators during feeding. A total of 47 apparently healthy and domesticated dogs from various households within Lubbock County of Texas were randomly assigned to each of the 4 feeding groups; i) Control (without probiotics); ii) L28 iii) L28 and commercial probiotics and iv) commercial probiotics. These dogs differed in breed, gender, and age. During the adjustment phase, the kibble without probiotics was fed to every dogs for 7 days irrespective of the groups assigned. On the 8th day (Day 0 of the treatment phase) the three probiotic groups were given their respective treatment food, whereas the control group was continuously fed with the non-probiotic kibble. The group fed with L28 alone or the combined probiotics (L28 + commercial probiotics) received the L28 at a dose of 106 CFU/dog/day, based on average consumption. Fecal samples from each dog were aseptically collected and subjected to microbial enumeration on days 3, 2 and 1 before feeding probiotics (to generate a baseline of the microbial indicators), and on day 5, 10, 20 and 40 of the treatment phase (to assess the impact of probiotics). Simultaneously, the fecal were screened for Salmonella with Real- Time BAX kit followed by selective enrichment, selective plating, and agglutination test for confirmation, before and during treatment. The group fed with combination of L28 and commercial probiotics showed a higher reduction in the fecal population of Generic E. coli, fecal coliforms, total-coliforms and, Entereobacteriaceae compared to the groups fed with the non-probiotic kibble, L28 or the commercial probiotics. Similarly, the group fed with combined probiotics had the highest proportion of dogs with greater than 1-log cycle reduction in the four microbial indicators. Like the control group, the group fed with Lactobacillus salivarius L28 alone or the commercial probiotics did not exhibit a significant reduction (p<0.05) in the microbial indicators over-time. Whereas, the group treated with combination of L28 and commercial probiotics at the given dose of L28 showed a significant reduction (P<0.05) in the fecal population of the indicators compared to baseline. However, the efficacy of L28 + commercial probiotics to reduce the indicators in the fecal samples depended on the duration of the feeding. Similarly, the effect of the supplement and its duration varied between the subjects in the group. A significant reduction (P<0.05) in all the indicators in the group was observed after 20 days of feeding. There was a rare presence of Salmonella in the dogs under study during baseline. The reduction in microbial indicators suggests the potential of L28 + commercial probiotics to reduce/control the growth of enteric-pathogens and modulate the balance of GI micro-flora towards healthier ones. This microbial shift could boost the gut health of the animal. Thus, L28 can be a promising component of the commercial probiotics formulation to add better functionality to kibbles for maintaining or improving GI health of pets and lowering incidence of zoonotic diseases in humans.Item Odor signature evaluation: Perspectives encompassing explosives and pathogen detection(2022-12) Gallegos, Shawna F.; Cañas-Carrell, Jaclyn E.; Prada-Tiedemann, Paola A.; Hall, Nathaniel J.; Anderson, Todd A.Canines have been utilized as biological detectors for centuries due to their instinctual drive to detect scent given off by prey making them the perfect hunting companion to humans. As time and technology have progressed, the use of canines as a detector has been expanded well beyond the hunting of prey. Canines are now trained and utilized for detection purposes in a wide variety of fields including explosives, narcotics, contraband, living and deceased humans, agriculture, currency, pests, and more recently medical diagnostic fields. The superior detection ability of the canine can be attributed to the significantly complex olfactory epithelium which provides for a large surface area of olfactory receptors, while the structure of their nasal cavity provides for efficient odor transport allowing for enhanced sensitivity to odor. There has been extensive research and effort into developing programs within the various fields of canine odor detection for trainers, handlers, and their canines. However, there is still a gap in knowledge in understanding the chemical odor signature of target odorants that the canine is specifically using when displaying the alert. It is known that canines can discriminate between odors and are also able to generalize while still correctly identifying the trained odorant. While research is currently ongoing, there is still limited knowledge in the chemical characterization of the odorants, i.e., the volatile organic compounds (VOCs) that are present in target odor sources. With technological advancements in analytical chemistry, a variety of questions about chemical makeup and odor profiles have surfaced in a number of areas. It has been reported that the compound diphenylamine is a common stabilizer used in explosives and smokeless powders. Plastic explosives such as trinitrotoluene (TNT) and composition 4 (C-4) have a number of compound identifiers including 2-ethyl-1-hexanol (2E1H). The identification of these compounds in a post-blast scenario can aid in identification of explosive components used in improvised or homemade explosives and provide evidence that may assist in the identification of a suspect. However, identification of these components before detonation can prevent terrorist events and loss of life. Optimal methods for delivery output have been validated using an in-house olfactometer, while simultaneously monitoring target volatile odor signatures above the headspace of an array of explosive classes. A 13-month longevity and persistence evaluation of smokeless powder indicated an expected fluctuation in the target odor volatile concentration of diphenylamine during active canine trials. Additionally, throughout the longevity monitoring, analytical detection of the target odorant was absent among some sample points. These results demonstrate a necessity for enhanced olfactory-based behavioral tools when utilizing biological detectors as analytical detection. Given that canine performance did not decrease among sampling trials it is evident there is a combination of VOCs rather than individual compounds present in the canine response to the odor profile. With respect to pathogen detection, current research trends are exploiting chemical odor profiles for medical diagnostics, disease prevention, and routine therapeutic monitoring. Using the highly virulent Clostridium difficile (C. diff), which is associated with a severe nosocomial infection, this study explored the chemical odor signature of this target pathogen. This infection causes increasingly higher morbidity and mortality rates and is common among the elderly and immunocompromised. The individual odor profile can be altered by disease and stress in the body which can be potentially utilized for identification and diagnostic purposes. As canines are utilized as detectors with explosives and various medical diagnostics that include infection, identification of volatile odor signatures emanating from targets of canine detection relevance has become ever more important. This study focuses on the coupling of analytical chemistry with canine training materials to understand the unique odor profile of Clostridium difficile (C. diff) to develop a safe and effective training aid for medical detection canine teams. Studies assessed C. diff inoculated media via an indirect passive headspace adsorption onto a Getxent tube followed by a SPME-GC/MS instrumental evaluation to chemically characterize emitted odor signatures. Evaluation of the longevity of the novel training aid was also studied to discern the persistence of the target odorant. As the field of canine odor detection continues to expand in applications of homeland security and medical detection, research into the related target odorants must expand on an equal level. Understanding these compounds both individually and in a mixture is key in developing an expanded knowledge base of canine response to trained odors as well as safe and effective training aid development, enhanced standardization of the canine odor detection field, expanded utilization for homeland security purposes, practical application in medical detection and diagnostic as well as further solidification of the scientific foundation presented within the legal sector.Item Odor signature evaluation: Perspectives encompassing explosives and pathogen detection(2022-12) Gallegos, Shawna; Cañas-Carrell, Jaclyn E.; Anderson, Todd A.; Hall, Nathaniel J.; Prada-Tiedemann, Paola A.Canines have been utilized as biological detectors for centuries due to their instinctual drive to detect scent given off by prey making them the perfect hunting companion to humans. As time and technology have progressed, the use of canines as a detector has been expanded well beyond the hunting of prey. Canines are now trained and utilized for detection purposes in a wide variety of fields including explosives, narcotics, contraband, living and deceased humans, agriculture, currency, pests, and more recently medical diagnostic fields. The superior detection ability of the canine can be attributed to the significantly complex olfactory epithelium which provides for a large surface area of olfactory receptors, while the structure of their nasal cavity provides for efficient odor transport allowing for enhanced sensitivity to odor. There has been extensive research and effort into developing programs within the various fields of canine odor detection for trainers, handlers, and their canines. However, there is still a gap in knowledge in understanding the chemical odor signature of target odorants that the canine is specifically using when displaying the alert. It is known that canines can discriminate between odors and are also able to generalize while still correctly identifying the trained odorant. While research is currently ongoing, there is still limited knowledge in the chemical characterization of the odorants, i.e., the volatile organic compounds (VOCs) that are present in target odor sources. With technological advancements in analytical chemistry, a variety of questions about chemical makeup and odor profiles have surfaced in a number of areas. It has been reported that the compound diphenylamine is a common stabilizer used in explosives and smokeless powders. Plastic explosives such as trinitrotoluene (TNT) and composition 4 (C-4) have a number of compound identifiers including 2-ethyl-1-hexanol (2E1H). The identification of these compounds in a post-blast scenario can aid in identification of explosive components used in improvised or homemade explosives and provide evidence that may assist in the identification of a suspect. However, identification of these components before detonation can prevent terrorist events and loss of life. Optimal methods for delivery output have been validated using an in-house olfactometer, while simultaneously monitoring target volatile odor signatures above the headspace of an array of explosive classes. A 13-month longevity and persistence evaluation of smokeless powder indicated an expected fluctuation in the target odor volatile concentration of diphenylamine during active canine trials. Additionally, throughout the longevity monitoring, analytical detection of the target odorant was absent among some sample points. These results demonstrate a necessity for enhanced olfactory-based behavioral tools when utilizing biological detectors as analytical detection. Given that canine performance did not decrease among sampling trials it is evident there is a combination of VOCs rather than individual compounds present in the canine response to the odor profile. With respect to pathogen detection, current research trends are exploiting chemical odor profiles for medical diagnostics, disease prevention, and routine therapeutic monitoring. Using the highly virulent Clostridium difficile (C. diff), which is associated with a severe nosocomial infection, this study explored the chemical odor signature of this target pathogen. This infection causes increasingly higher morbidity and mortality rates and is common among the elderly and immunocompromised. The individual odor profile can be altered by disease and stress in the body which can be potentially utilized for identification and diagnostic purposes. As canines are utilized as detectors with explosives and various medical diagnostics that include infection, identification of volatile odor signatures emanating from targets of canine detection relevance has become ever more important. This study focuses on the coupling of analytical chemistry with canine training materials to understand the unique odor profile of Clostridium difficile (C. diff) to develop a safe and effective training aid for medical detection canine teams. Studies assessed C. diff inoculated media via an indirect passive headspace adsorption onto a Getxent tube followed by a SPME-GC/MS instrumental evaluation to chemically characterize emitted odor signatures. Evaluation of the longevity of the novel training aid was also studied to discern the persistence of the target odorant. As the field of canine odor detection continues to expand in applications of homeland security and medical detection, research into the related target odorants must expand on an equal level. Understanding these compounds both individually and in a mixture is key in developing an expanded knowledge base of canine response to trained odors as well as safe and effective training aid development, enhanced standardization of the canine odor detection field, expanded utilization for homeland security purposes, practical application in medical detection and diagnostic as well as further solidification of the scientific foundation presented within the legal sector.Item Stimulus control of odorant concentration: Pilot study of generalization and discrimination of odor concentration in canines(MDPI, 2021) DeChant, Mallory T.; Bunker, Paul C.; Hall, Nathaniel J.Despite dogs’ widespread use as detection systems, little is known about how dogs generalize to variations of an odorant’s concentration. Further, it is unclear whether dogs can be trained to discriminate between similar concentration variations of an odorant. Four dogs were trained to an odorant (0.01 air dilution of isoamyl acetate) in an air-dilution olfactometer, and we assessed spontaneous generalization to a range of concentrations lower than the training stimulus (Generalization Test 1). Dogs generalized to odors within a 10-fold range of the training odorant. Next, we conducted discrimination training to suppress responses to concentrations lower than a concentration dogs showed initial responding towards in Generalization Test 1 (0.0025 air dilution). Dogs successfully discriminated between 0.0025 and 0.01, exceeding 90% accuracy. However, when a second generalization test was conducted (Generalization Test 2), responding at the 0.0025 concentration immediately recovered and was no different than in Generalization Test 1. Dogs were then tested in another generalization test (Compound Discrimination and Generalization) in which generalization probes were embedded within discrimination trials, and dogs showed suppression of responding to the 0.0025 concentration and lower concentrations in this preparation. These data suggest dogs show limited spontaneous generalization across odor concentration and that dogs can be trained to discriminate between similar concentrations of the same odorant. Stimulus control, however, may depend on the negative stimulus, suggesting olfactory concentration generalization may depend on relative stimulus control. These results highlight the importance of considering odor concentration as a dimension for generalization in canine olfactory research.Item The effect of swine's semiochemicals on pigs' behavior, physiology and production(2019-05) Aviles-Rosa, Edgar O.; McGlone, John J.; Hall, Nathaniel J.; Rakhshandeh, Anoosh; Thompson, Jonathan E.; Surowiec, KazThe objectives of this doctoral dissertation were to 1) evaluate how coprophagy benefits piglets, 2) the identification of maternal semiochemicals that might be acting as a fecal maternal pheromone, and 3) to evaluate if putative maternal semiochemicals (FMS) could be used to improve wean pig welfare and performance. The effect of coprophagy on nursing piglet hematology, behavior, and performance were assessed by depriving piglets of maternal feces the first seven days of age. Deprivation of maternal feces had no statistically significant effect on piglet behavior, RBC, HCT, and Hb (P > 0.05). Piglets with access to maternal feces (control) had better pre- and post-weaning performance than piglets deprived of maternal feces for the first seven days of age. Deprivation of maternal feces reduced piglets average daily gain and feed intake by 10 %. Piglets with access to maternal feces the first seven days of age weighed 9.6 kg more at 123 d post-weaning compare to the ones deprived of maternal feces the first seven days of age (P < 0.05). To identify fecal maternal semiochemicals that might be acting as a maternal fecal pheromone and inducing coprophagy, fecal samples were collected from eight sows during gestation and lactation. Fecal semiochemicals were extracted with a SPE procedure and analyzed by GC/MS. Results showed that lactation increased the fecal concentrations of skatole and myristic acid (P < 0.05). During gestation the concentration of skatole and myristic acid were 11. 69 µg/g and 66.24 µg/g respectively. However, during lactation the concentration of these analytes significantly increased by 62 % and 11 % respectively (P < 0.05). A free-choice preference assessment showed that piglets had a preference for feeders sprayed with 5 mL of a mineral oil solution containing skatole (4.5 mg) and myristic acid (9.0 mg) (P < 0.05), but not either molecule alone. The application of skatole and myristic acid to the feeders of weaned pigs statistically reduced piglet aggression by 30 % and increased feeding behavior by 35 % the first 24 h post weaning (P < 0.05). No difference in performance was observed over a 28-d period. Overall, because having access to maternal feces improved piglet performance by 10 %, coprophagy presents as a beneficial behavior to piglets. In addition, skatole and myristic acid might be acting as a multicomponent maternal semiochemical that attracts piglets and has a calming effect at weaning.Item The evaluation of canine training aids over time on working dog performance(2018-05) Alejandro, Lauren A.; Prada, Paola A.; Hall, Nathaniel J.; Thoen, Megan A.Canines (K9) are the front line of defense in detecting narcotics by police and military working units across the nation. The way canines learn how to detect narcotics is by using small amounts of actual narcotics known as training aids or with training aid mimics. These mimics are synthetically made and replicate the targeted narcotic scent (pseudo). Even though there’re a number of research studies exploring canine detection in terms of olfaction capabilities, identification of target odor volatiles, to name a few, there are no existing studies evaluating the lifespan of narcotic canine training aids, defined as the length of time in usage during training. In this study, two types of training aids are be evaluated: real narcotic training aids (cocaine and heroin), that range in age from fresh to up to 10 years of age and commercially bought pseudo narcotic scents (cocaine and heroin). The main objective is to perform an instrumental evaluation in terms of the volatile odors being emitted for any given sample in relation to their respective age to see how their lifespan affects K9 detection. To do so, the evaluation period included: freshly acquired, 2 week, 4 week, 6 week, and up to 12 week old in order to observe the dissipation rate of chemical vapors in a controlled setting. Headspace analysis of all training aids was collected with Solid Phase Microextraction (SPME) and analyzed with Gas Chromatography-Mass Spectrometry (GC-MS) to obtain a chemical odor profile. Simultaneously, field testing with four local police department narcotic detection canines teams (all male Belgian Malinois breed of various ages) occurred to observe K9 alert performance with respect to training aid age. The hypothesis is that over time, training aid vapors decrease in concentration and provide less of the chemical odor signature for the canines to detect, which thereby decreases alert performance. The findings include primary Volatile Organic Compounds(VOC) (80% in quality abundance and frequency occurrence in narcotic types) for heroin: ethanone,1-(2-hydrophenyl) -, phenol, and undecane, 5-methyl-. Primary VOC’s for cocaine included: ethanol, 2-butoxy-, benzene, 1,3-dimethyl-, p-xylene. Using multi-factorial ANOVA modeling there was no statistical difference between the amount of these target VOCs in either heroin or cocaine with respect to their age or narcotic training aid type. Although no consistent chemical odor profile was found across the different types of training aids tested, canines were able to alert with great accuracy, obtaining an average of 96% Positive Predictive Value (PPV) in alerts for heroin and 100% PPV for cocaine. Average Negative Predictive Values (NPV) for heroin yielded 91% and 94% for cocaine. The variation of VOC odor vapor highlights how canines, no matter the age or narcotic type, are able to learn a distinct odor and follow its odor pattern as it changes over time to identify it. This directly impacts biological detection of narcotics by presenting scientifically based evidence on the chemical odor profiles of various drug types and their effect on efficient and reliable canine detection in the field. This research project attends to the need of standardizing forensic canine detection practices within the United States national defense at home and abroad.