Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

There is a recognized need for additional research that produces empirical data on positive youth development (PYD) frameworks, as well as PYD impacts and roles amongst human-animal interactions (HAI) and youth. This study used inputs and outcomes from the 4-H Formula for Success to identify and describe components of the 4-H dog program within one state as case studies. Inputs included skill-building, meaningful leadership, and long-term relationships with caring adults. Outcomes included the 5 C's: caring, character, confidence, connection and competence. Three counties (cases) were identified, and participants were interviewed about their 4-H dog program experiences. 4-H youth, parents, volunteers and agents were included. A total of 19 interviews were transcribed and coded for themes that fit within the 4-H Formula for Success within the context of each case. Findings indicate a strong presence of inputs that are specific to dog programming, as well as some outcomes and emergent themes, including accessibility, motivation to join and COVID implications. Dog industry professionals greatly contributed to the skill-building and meaningful leadership opportunities for 4-H youth. Connection and Competence were the most frequently coded outcomes across the cases. Participants described the 4-H dog program as accessible due to cost, small size and simple housing requirements, compared to livestock or equine projects. A shared interest in dogs was the primary motivation to join 4-H dog clubs and led to strong connections or bonds between members. Limitations of this study are related to a low participant pool in one case, and recall accuracy and cognitive ability of 4-H youth to recognize and name their perceived outcomes. Recommendations for practice are included for 4-H agents and 4-H volunteers to start, promote or strengthen 4-H dog programs in any location by being intentional when recruiting 4-H volunteers, and planning educational programming. This program can be promoted as more accessible compared to large animal science 4-H programs such as livestock or equine based on data provided by participants in all three cases within diverse contexts. There are several recommendations for further research beyond this study including a longitudinal continuation of this model, replicating this study in other states to examine other 4-H dog programs, or replicating this study for other 4-H program areas. / Master of Science in Life Sciences / The 4-H dog project is one of many animal science projects available to youth enrolled in 4-H across the nation. Unfortunately, it is not nearly as recognizable or flashy as market livestock or equine and is often overlooked by families and agents alike. This study is a case study of three county 4-H dog programs, looking at what positive youth development inputs exist to promote positive youth development outcomes in the youth enrolled. 4-H members, parents, volunteers and agents were interviewed from three counties that had existing 4-H dog programs in each county as well as state 4-H dog opportunities. Each case presented opportunities for skill-building and meaningful leadership for 4-H members, as well as relationships with caring adults that led to the development of 4-H PYD outcomes including caring, connection, character, competence and confidence. Dog industry professionals were found to be a very valuable asset within each 4-H dog program. The 4-H dog program facets of each case are described in detail as well as how they contribute to outcome development. Limitations and recommendations for practice and future research are included to assist 4-H agents and volunteers in starting, strengthening or promoting 4-H dog programs in any location. A model created by the researcher based on findings is presented to assist 4-H agents and volunteers for future research or practice.

The objective of this prospective pilot study is to assess the feasibility of a minimally invasive, integrated endoscopic hemilaminectomy in chondrodystrophic dogs with clinically relevant Hansen type 1 intervertebral disc extrusion (IVDE). Study subjects included five client-owned chondrodystrophic dogs under 15kg with an acute, single site IVDE between T10 and L5 of less than 90 days duration and no loss of deep pain perception. The extent of the extrusion could not exceed 2/3 the diameter of the cannula to be used as defined by magnetic resonance imaging (MRI). A postoperative MRI was performed to assess remaining spinal cord compression. If significant compression remained, patients returned to surgery for a standard, open hemilaminectomy. Only the first dog required conversion to an open approach which resulted in adequate decompression. The same dog had a significant surgical complication of iatrogenic damage to the spinal cord during the minimally invasive approach. The other 4 dogs had no complications and achieved adequate spinal cord decompression. Three dogs eventually returned to normal neurologic status and another was improved compared to presentation. One dog was euthanized for reasons unrelated to IVDE. The authors conclude that a minimally invasive, integrated endoscopic hemilaminectomy is a feasible approach and can allow for adequate decompression of the spinal cord secondary to acute, single-site extrusion. Endoscopic approaches have a steep learning curve and extra care is required in the learning phase to avoid complications. Further studies are warranted to compare the safety and efficacy of this technique to a standard approach. / Master of Science / Acute intervertebral disc extrusion, or "slipped disc", is a common spinal emergency in dogs, particularly in small, chondrodystrophic breeds like dachshunds. Surgery is aimed at removing the disc material causing spinal cord compression. The traditional approach, known as a hemilaminectomy, involves elevating the muscles along the spine over multiple vertebrae, followed by creating a window in the bone with a surgical burr. Minimally invasive spinal surgery that minimizes the elevation of muscles, has the potential to decrease postoperative pain, surgical time, hospital stay, intraoperative blood loss and recovery time. This study was designed to assess the use of a minimally invasive, integrated endoscopic approach to a hemilaminectomy in clinical patients. Five dogs were enrolled with an acute, single site intervertebral disc extrusion between T10 and L5 that was no more than 2/3 the diameter of the cannula to be used in surgery. Study subjects were chondrodystrophic breeds under 15kg. All dogs had intact deep pain perception. Spinal cord compression was assessed by magnetic resonance imaging (MRI) both before and after a minimally invasive approach. If significant acute compression remained, a standard, open approach was immediately performed. Spinal cord decompression was adequate in all but one dog which required a second procedure to remove the remaining material. This same dog had accidental damage to the spinal cord during the minimally invasive approach. Three dogs eventually returned to normal neurologic status and the dog that required a second, traditional approach surgery eventually improved compared to his preoperative status. One dog was improving but euthanized eight days later due to chronic disease unrelated to IVDE. This approach is feasible for decompressing the spinal cord after a single site, acute intervertebral disc extrusion in a chondrodystrophic dog. However, like any endoscopic surgery, previous experience is of great benefit and errors are more likely to happen during the learning phase.

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for their analgesic, anti-pyretic and anti-inflammatory properties in both human and veterinary patients. Topical ophthalmic NSAIDs are commonly employed in the management of intraocular inflammation (uveitis), corneoconjunctival inflammatory disease and pre-operatively to prevent intraoperative miosis during cataract surgery. Despite their routine application in these clinical scenarios, little is known regarding the corneal penetration and relative anti-inflammatory efficacy of the available topical ophthalmic NSAIDs in the dog. Decisions regarding which of these agents to employ are therefore based upon factors such as cost and ease of acquisition as opposed to established efficacy. Objectives: To investigate the relative intraocular penetration and anti-inflammatory efficacy of two commonly utilized topical ophthalmic NSAIDs in dogs, diclofenac 0.1% and ketorolac 0.5%. Animals: Twenty-two client owned dogs (22 operated eyes) presenting to the VTH ophthalmology service for routine cataract surgery for mature or hypermature cataract. Methods: Subjects were randomized to be treated with either topical ketorolac 0.5% or topical diclofenac 0.1% ophthalmic solutions at specified times in the 24-hour period pre-operatively. Aqueous humor samples were obtained intra-operatively and stored for subsequent evaluation of drug concentrations and prostaglandin E2 (PGE2) concentrations via ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) and enzyme-linked immunoassay (ELISA) analysis, respectively. Results: Median aqueous humor drug concentrations were significantly higher in dogs treated with ketorolac 0.5% (1311.6 ng/mL) compared to those treated with diclofenac 0.1% (284.9 ng/mL). There was no significant difference in aqueous humor PGE2 concentrations between the two treatment groups. No significant association was determined between aqueous humor drug concentration and PGE2 concentration. There was no significant association between diabetic status and aqueous humor drug concentration or PGE2 concentration in either group. Conclusions and clinical importance: This study suggests that topical ketorolac 0.5% and diclofenac 0.1% are efficacious in decreasing aqueous humor PGE2 concentrations and are equally suitable for use based on their comparable anti-inflammatory profiles. The results of these assays provide clinically relevant information regarding intraocular penetration and anti-inflammatory efficacy of these medications in dogs with cataract. / Master of Science / Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for their analgesic, anti-pyretic and anti-inflammatory properties in both human and veterinary patients. Topical ophthalmic NSAIDs are commonly employed in the management of intraocular inflammation (uveitis), corneoconjunctival inflammatory disease and pre-operatively to prevent intraoperative miosis during cataract surgery. Despite their routine application in these clinical scenarios, little is known regarding the intraocular penetration and relative anti-inflammatory efficacy of the available topical ophthalmic NSAIDs in the dog. Decisions regarding which of these agents to employ are therefore based upon factors such as cost and ease of acquisition as opposed to established efficacy. Efficacy of topical anti-inflammatory medications in controlling intraocular inflammation is primarily related to the ability of the medication to penetrate the cornea and its efficacy at suppressing inflammatory mediators. The purpose of this study, therefore, is to investigate the relative intraocular penetration and anti-inflammatory efficacy of two commonly utilized topical ophthalmic NSAIDs in dogs, diclofenac 0.1% and ketorolac 0.5%. Twenty-two dogs presenting to the VTH ophthalmology service for routine cataract surgery with the presence of a mature or hypermature cataract were enrolled in a prospective, randomized clinical trial. Subjects were treated with either topical ketorolac 0.5% or topical diclofenac 0.1% ophthalmic solutions at specified times in the 24-hour period pre-operatively. Aqueous humor samples were obtained intra-operatively and stored for subsequent evaluation of drug concentrations (n=22) and prostaglandin E2 (PGE2) concentrations (n=19) via ultra performance liquid chromatography (UPLC) and enzyme-linked immunoassay (ELISA) analysis, respectively. Treatment with topical ketorolac 0.5% resulted in higher median aqueous humor drug concentrations when compared to treatment with diclofenac 0.1% (1311.6 ng/mL vs. 284.9 ng/mL). However, there was no significant difference in anti-inflammatory efficacy when comparing PGE2 concentrations between the two groups. Furthermore, no significant association was determined when drug concentration was directly compared with PGE2 concentration. The results of these assays suggest that topical ketorolac 0.5% and diclofenac 0.1% are equally suitable for use based on their comparable anti-inflammatory profiles, and provides clinically relevant information regarding intraocular penetration and anti-inflammatory efficacy of these medications in dogs with cataract.

Many of the presently approved somatic gene therapy protocols involve reimplantation of genetically engineered autologous cells into a patient. A potentially more cost-effective approach to the delivery of therapeutic gene products is the use of a universal recombinant cell line that can be implanted into a number of patients with the same product requirements. Enclosure of these non-autologous cells inside a permselective microcapsule membrane would permit the diffusion of the recombinant product but prevent entry of the host’s immune mediators. The clinical efficacy of this approach has been demonstrated by the implantation of recombinant fibroblasts and myoblasts to correct mutant phenotypes in murine models of diseases such as dwarfism (Al-Hendy et al., 1995) and lysosomal storage disease (Bastedo, 1994). In the first part of this thesis, a new microcapsule type was created that incorporated a combination of traits from both alginate-poly-L-lysine-alginate and barium-alginate microcapsules. The new, barium-poly-L-lysine-alginate microcapsule was cross-linked with BaCl2 and received a poly-L-lysine, and a second alginate coat. The three different types of microcapsules were compared with respect to encapsulated cell viability, proliferation and secretion in vitro. Results of these analyses demonstrated that cells inside alginate-poly-L-lysinealginate microcapsules had higher viability and a greater proliferation rate than did cells inside either barium-alginate or barium-poly-L-lysine alginate microcapsules. However, secretion from the alginate-poly-L-lysine alginate microcapsules was lower than from either of the barium-alginate types, and the two types of barium-alginate microcapsules, formulated with a higher alginate concentration, were more resistant to well-defined fluid shearing forces, than was the calcium alginate microcapsule. No significant difference in any of the parameters measured was observed between the barium-alginate and bariumpoly-L-lysine alginate microcapsule types. In the second part of this thesis the three different types of microcapsules, each containing canine MDCK cells secreting ~20 ng/106 cells/hr of human growth hormone (hGH) were implanted into the peritoneal cavities of a large animal model. The microencapsulated cells were able to deliver recombinant human growth hormone to the circulation of dogs at levels nearly 100 % higher than human physiological levels. In contrast, implantation of unencapsulated recombinant cells resulted only in short-term delivery of hGH to the dogs. The level of titre of anti-hGH antibodies was monitored in the experimental and control animals, and its increase was determined to be associated with the disappearance of the human growth hormone from the circulation of the dogs. The BaCl2 cross-linked capsules with the higher alginate concentration lasted longer in vivo, confirming their superior mechanical integrity relative to the alginate-poly-L-lysine alginate type. The presence of the microcapsules in the peritoneum of the dogs was associated with localized inflammation of the omentum, and mild lymphadenitis. This pathology, combined with varying degrees of fibrotic overgrowth of the microcapsules with increasing time in vivo, suggests that modifications must be made in order to improve the biocompatibility of alginate microcapsules. In conclusion, modifications of alginate microcapsules, such as the cross-linking with barium cations, the use of higher alginate concentrations and lamination with polyL-lysine alginate have contributed to the mechanical stability of the capsules and permitted the long-term delivery of recombinant gene products using non-autologous cells. This study has highlighted some of the issues to be addressed during pre-clinical studies in large animal models, in order to determine the efficacy of this new technology for humans. / Thesis / Master of Science (MS)

Research in grassland ecosystems worldwide has highlighted the crucial role many burrowing herbivore mammals provide as so-called “ecosystem engineers”. Many of these examples come from North America and have mostly been focused on Prairie Dogs (Cynomys sp.), which, due to their burrowing and grazing activities, are considered as a species of high ecological importance. Multiple studies have shown that their loss reduces grassland ecosystem functions and that their activities increase plant, arthropod, bird and mammal biodiversity, grassland heterogeneity, provide benefits to cattle, among many other key ecological roles. However, prairie dog species are distributed throughout multiple landscapes in North America, and most of the studies have been on mixed prairie grasslands. It is therefore not surprising that, when comparing the effects of different prairie dog species across ecoregions, the role of prairie dogs is not as clear and results vary, depending on spatial context, type of grasslands, climate and environmental conditions. Yet, grasslands are considered as some of the most highly threatened ecosystems, having high rates of conversion, desertification and biodiversity loss. Therefore, it is imperative to understand the effects prairie dog species have on the ecosystem. In this thesis, I focus on the Mexican prairie dog (C. mexicanus), a species in drastic decline due to habitat loss, caused by agriculture, overgrazing, human settlement, fragmentation, diseases (e.g. plague) and past eradication programs. C. mexicanus is considered endangered by the IUCN red list of threatened species and The Convention of International Trade in Endangered Species of Wild Fauna and Flora. It is also endemic to the Grassland Priority Conservation Area (GPCA) of El Tokio, located in Northeast Mexico within the Chihuahuan desert ecoregion and designated as a GPCA by the Commission for Environmental Cooperation (a cooperation between Canada, U.S. and Mexico) in 2009. Grasslands within GPCA El Tokio are highly fragmented as a result of many years of intense agricultural practices and other anthropogenic activities and around 90% of the original grasslands have been lost. However, it is considered an area of ecological importance due to its unique vegetation and edaphic associations, as well as being a key habitat for migratory birds. Up until now, very few studies have explored the role C. mexicanus has on plant taxonomical diversity and soil properties. Moreover, no studies focusing on prairie dogs have looked into the effect the species has on plant functional diversity or soil properties. Furthermore, GPCA El Tokio is a data-scarce area. Therefore, at this point, basic information and system understanding are urgently needed in order to identify which conservation efforts are most promising and which specific sites these efforts should focus on. Understanding the influence of prairie dog disturbance on vegetation parameters (taxonomic and functional), soil properties and their interaction with environmental conditions through time, will increase knowledge on the risks and vulnerability of grasslands, promoting solutions that can support grassland management. Furthermore, there is a clear gap in the literature about the varying effects of prairie dogs depending on different grassland types and environmental conditions. To study such conditions, I first classified and controlled for factors that could influence prairie dog ecosystem engineering effects addressing the following two general questions: (1) Which grassland types are present in GPCA El Tokio? (2) Do the different grassland types present in GPCA El Tokio influence prairie dog colony sizes and burrow density? When influencing factors were confirmed, I then assess the effects of prairie dog disturbance on vegetation and soil to answer the following questions: (3) Are there clear distinctions across GPCA El Tokio grassland environmental variables? (4) Do the different grassland types present in GPCA El Tokio influence prairie dog colony sizes and burrow density? To do so I selected a representative sample of sites covering the varying environmental conditions present in GPCA El Tokio grasslands, a data-driven clustering approach was used. Once clusters were defined, average burrow density was estimated from remote sensing imagery. To study vegetation measures I first, sampled plant species (92 species and 28 families and 6 traits) to obtain taxonomical and functional diversity measures, and obtained variables related to nutrient availability, carbon and climate regulation, and water regulation and purification. To study the effects on soil a total of 11 soil properties were obtained (382 samples were analyzed). Field work was done during the wet season and repeated during the dry season to obtain season variations of all measures. Soil measures were further obtained at depths of 0-10cm and 10 to 20cm. Results from the study classify GPCA El Tokio into 8 different grassland types with 4 clusters being the most dominant, named Agriculture, Arid, Calcareous, Mountain. I found agricultural grasslands had significantly lower colony sizes compared to calcareous grasslands when outliers were considered, but no differences when outliers were removed and burrow density varied depending on the grassland type, with mountain grasslands having a significantly lower burrow density compared to agricultural and calcareous grasslands. Regarding the effects of prairie dogs on vegetation and soil my findings suggest that functional metrics and community weighted mean (CWM) analyses responded to interactions between prairie dog disturbance, grassland type and season, whilst species diversity and cover measures were less sensitive to the role of prairie dog disturbance. I found weak evidence that prairie dog disturbance has a negative effect on vegetation structure, except for minimal effects on C4 and graminoid cover, but which depended mainly on season. Grassland type and season explained most of the effects on plant functional and taxonomic diversity as well as CWM traits. In the case of soil properties WOP grasslands tended to have higher nutrient availability than WP grasslands. However, mounds played a key role within WP grasslands. Mounds reduce compaction and increase nutrient levels of soil organic carbon, nitrogen, potassium, magnesium, and phosphorus. Such an effect was particularly present in calcareous and arid grasslands, and in many cases the effect was enhanced under wet conditions. In general, the effect of disturbance on soil property changes was dependent on environmental conditions. Overall, my study shows evidence that grassland type and season have a stronger effect than prairie dog disturbance on the vegetation of this short-grass, water-restricted grassland ecosystem.:3 TABLE OF CONTENTS Declaration of conformity 2 1 Acknowledgments 3 2 Extended Summary 5 4 List of Figures 11 5 List of Tables 13 1 Introduction 1 1.1 Importance of grasslands 1 1.2 Grassland conservation and ecosystem engineers 2 1.3 Prairie dogs: ecosystem engineers of grasslands in North America 3 1.4 Distribution of prairie dogs across North American grasslands 6 1.5 Current threats and conservation of the Mexican prairie dog C. mexicanus 7 1.6 Research questions, aims and objectives 9 2 Scientific background 13 2.1 Differences in grassland definitions and classifications 13 2.2 Dryland biases in grassland research 13 2.3 Research gaps on C. mexicanus 15 2.4 Functional diversity and disturbance 16 2.5 Soil complexity and limited research 17 3 Study Area: Grassland Priority Conservation Area of El Tokio 19 3.1 General overview 19 3.2 Bioregions, geology, topography and soils 20 3.3 Climate 23 3.4 Ecoregions, Land cover and Biodiversity 24 3.5 Anthropogenic activities and environmental issues 28 4 Assessing and classifying factors that could influence prairie dog ecosystem engineering effects 31 4.1 Data-driven identification of grassland types 33 4.1.1 Introduction 33 4.1.2 Methods 33 4.1.3 Results 36 4.1.4 Discussion and conclusion 39 4.2 C. mexicanus colony trends and differences across grassland types 41 4.2.1 Introduction 41 4.2.2 Methods 42 4.2.3 Results 48 4.2.4 Discussion and conclusion 52 5 Prairie dog disturbance effects on vegetation and soil across different grassland types and seasons 55 5.1 General methodology 57 5.1.1 Selection of grassland locations 57 5.1.2 Defining study sites and plots 58 5.1.3 Vegetation and soil sampling design 59 5.2 The effect of C. mexicanus on taxonomical and functional diversity across different seasons and grassland types 61 5.2.1 Introduction 61 5.2.2 Methods 63 5.2.3 Results 65 5.2.4 Discussion and conclusion 72 5.3 Soil property responses to the presence of C. mexicanus and its mounds across different grassland types, seasons and depths 77 5.3.1 Introduction 77 5.3.2 Methods 78 5.3.3 Results 81 5.3.4 Discussion and conclusion 88 6 Synthesis 95 6.1 Key findings 95 6.2 Management and Conservation opportunities 97 6.2.1 Designing management plans to suit existing environmental conditions 97 6.2.2 Functional diversity: an opportunity to identify patterns of vegetation across environmental conditions and scales. 98 6.3 Future research 99 6.3.1 Exploration of spatial and temporal effects 99 6.3.2 Mechanistic understanding of disturbance dynamics 100 6.3.3 A need for plant and soil ecological data 101 7 References 103 8 Appendix 131 8.1 Appendix 1. Prairie dog research reference list 132 8.2 Appendix 2. List of individual colonies with areas and other relevant information 140 8.3 Appendix 3. Historical and present colony data. 142 8.4 Appendix 4. Correlation results 144 8.5 Appendix 5. Top 3 models 146 8.6 Appendix 6. Species list per grassland type. 151 8.7 Appendix 7. Correspondence analysis (CA) for each grassland 154 8.8 Appendix 8. Post-hoc results 155 8.9 Appendix 9. Top 3 dominant species. 157 8.10 Appendix 10. HPD credible interval and ROPE. 159

This thesis regards the design process of a test rig for a new type of clutch. To save excessive fuel losses in heavy vehicles, a dog clutch has been designed with elastic engagement to lower peak torque. Currently, there is no way of testing this clutch. The purpose of this thesis is therefore to design a test rig that allows physical testing of this newly developed clutch. The thesis describes how suitable tests/measurements are found to indicate clutch functionality. By following a design process, these tests/measurements are incorporated in a test rig design. Initially, requirements were set. With these requirements, concepts have been generated. After some reviewing and improving, one final concept has been chosen. This concept has been designed using separate subsystems. When integrating these subsystems, a final design is realised. The final design measures the axial positions of components inside the clutch. It also measures torque and speed of the input and output. This all while having a variable input speed, engagement force, output braking torque, and output rotational inertia. The test rig is suitable for long-term testing to test wear of the different clutch components. Advice on future works has been given to the company based on the achieved results.

Play therapy and animal-assisted therapy are two specialized modalities within the field of counseling. Child-centered play therapy (CCPT) is a specific theoretical approach to play therapy that regards the therapeutic relationship as the primary healing factor. With much empirical support, CCPT is considered an effective mental health treatment option for working with children. Animal-assisted therapy in counseling (AAT-C) is acknowledged in the literature as a supplemental treatment modality to an existing counseling practice. Although past researchers have shown support for AAT-C as well as CCPT, there is a current dearth of literature examining the integration of these approaches. The present study sought to understand the approach of incorporating a therapy dog into child-centered play therapy while maintaining theoretical consistency. Using a constructivist grounded theory approach, I facilitated child-centered canine-assisted play therapy (C3APT) services for four children and reviewed the sessions with expert supervisors in AAT-C and CCPT. Three major themes emerged from the data: (a) principles of C3APT, (b) procedures of C3APT, and (c) relational dynamics. Implications for clinical practice and training of both therapy dogs and C3APT practitioners are also discussed.

Dog trainers sometimes teach verbal cues by saying the cue as the dog is performing the desired behavior. However, there is disagreement about when to say the cue. In this study, a pet dog was trained to go to three different apparatus, the cue for each of which was given at a different time, in a multi-element design. The cue "hoop" was given just as the dog began to move to the hoop apparatus. The cue "carrier" was given as the dog was stepping into the carrier apparatus. The cue "platform" was given after the dog was sitting on the platform apparatus. To test if the dog had learned the cues, the trainer had the dog sit and gave the cue. During testing, if only the correct apparatus was present, the dog responded to all three cues. However, when all three apparatus were present, the dog only responded correctly to the "hoop" cue. This suggests that giving the cue just as the learner is beginning to perform the desired behavior is the most effective teaching method.

Deva Plus Dog is a look at the life of a teenage girl singularly devoted to the sport of dog agility. The film explores how relationships develop and evolve in the high stakes world of competition, and how an alternative lifestyle impacts a youth’s coming of age.