An investigation into the use of infrared thermography as a tool to assess the physiological stress response in the horse

The experiments reported in this thesis investigated the use of temperature measurement using infrared thermography (IRT) as an objective, non-invasive method to identify the physiological stress response in the horse. The primary area of investigation was the eye area within the medial posterior palpebral border of the lower eyelid and the lacrimal caruncle as in existing work in other species. The application of these findings to horse management and welfare was discussed. Horses were exposed to potentially stressful situations that were acute (<20 seconds), short term (ten minutes) and long term or repetitive (one week) in duration. Temperature was measured using IRT in addition to measurement of salivary cortisol, faecal corticosterone and behavioural assessment, all of which are currently accepted measures of the stress response. IRT was shown to be an unsuitable method to assess acute stress in the horse due to the species specific behavioural response of flight. Rapid evasive movement of the horse meant that recording temperature using a thermal camera was difficult. A modified experimental design may have made it possible to capture the thermal response to acute stress however restraint of the horse would have been stressful in itself and confounded results

Monitoring changes in skin temperature associated with exercise in horses on a water treadmill by use of infrared thermography

Infrared thermography (IRT) was used to assess surface temperature change as an indirect measure of muscle activity and exercise associated changes in blood flow in the working hind limb muscles of horses (n¼7) undergoing water tread mill exercise. Three treatments were investigated including the treadmill ran dry (TD), water at the height of the proximal interphalangeal joint (PIP) and water at the height of the carpus (CP). Maximum skin surface temperature was recorded from the region of these mitendinosus muscle during exercise at each water height. There was a significant difference in surface hind limb temperature between exercise on the water treadmill ran dry and with water at the height of the PIP and CP (Po0.0001) with hotter temperatures recorded during the TD treatment. There was a greater increase in surface temperature of the hind limbs from preexercise to maximum temperature during the PIP and CP treatments when compared to the TD treatment, however, this was not significant (P¼0.58). There was no significant difference in surface hind limb temperature found between exercise in water at the height of the PIP and water at the height of the CP. The findings from this study suggest that IRT is able to non-invasively detect muscle activity and associated changes in blood flow whilst horses are exercised on a water treadmill. IRT could potentially be used as an alternative method to assess muscle activity and temperature change in an aquatic environment where existing methods present methodological challenges

Glucocorticoid assessment in the domestic horse: the impacts of time and climatic variables on sample integrity

Background: Assessment of faecal glucocorticoid metabolites (FGM) offers a noninvasive method of monitoring adrenal activity in domestic horses. Samples are collected on an opportunistic basis and, if they are not fresh or have been exposed to the elements before they are identified, may not accurately reflect FGM concentrations. Objectives: To explore the impact of a range of environmental conditions upon the integrity of FGM levels in equine faeces. Study design: In vitro experiment. Method: Equine faeces were exposed to six controlled environmental conditions intended to simulate a range of weather and seasonal patterns (temperate climate, high heat, high heat and rainfall, temperate climate and rainfall, high heat/temperate climate, freeze/thaw) over a period of 5 days. FGM were quantified using an enzyme-linked immunoassay. Results: Faecal samples exposed to room temperature and high heat demonstrated significant increases in FGM levels over time. No changes in FGM levels were observed in the remaining treatments. Main limitations: The study should be repeated in field conditions and with known high and low levels of FGM to further inform sampling regimes. Conclusions: Adrenal monitoring in the domestic horse should be performed with consideration of the impact of climate on the integrity of faecal samples in order to further inform sampling schedules and improve the reliability of results

Evaluation of thermal pattern distributions in racehorse saddles using infrared thermography

The impact of a rider’s and saddle’s mass on saddle thermal pattern distribution was evalu ated using infrared thermography (IRT). Eighteen racehorses were ridden by four riders with their own saddle. Images of the saddle panels were captured at each of six thermographic examinations. On each image, six regions of interest (ROIs) were marked on the saddle panels. The mean temperature for each ROI was extracted. To evaluate the influence of load on saddle fit, 4 indicators were used: ΔTmax (difference between the mean temperature of the warmest and coolest ROI); standard deviation of the mean temperature of the six ROIs; right/left; bridging/rocking and front/back thermal pattern indicator. Incorrect saddle fit was found in 25 measurements (23.1%) with ΔTmax greater than 2˚C. The relationships between rider and saddle fit as well as saddle fit and horse were significant (p<0.001). An average ΔTmax in rider A was significantly higher than in other riders (p<0.001). The right/left thermal pattern differed significantly from the optimal value for riders A and B; while the bridging/rocking thermal pattern differed significantly from this value for riders A, C and D (p<0.05). Front saddle thermal pattern was most frequent for rider A (41.5%), whereas back saddle thermal pattern was most frequent for rider C (85.7%). Measurement of the mean temperature in 6 ROIs on saddle panels after training was helpful in assessing the influence of rider and saddle mass on saddle fit. IRT offered a non-invasive, rapid and simple method for assessing load on thermal pattern distribution in race saddles.info:eu-repo/semantics/publishedVersio

Environmental impact on faecal glucocorticoid metabolite concentrations in Grevy's Zebra (Equus grevyi)

The non-invasive nature of faecal glucocorticoid metabolite (FGM) assessment means that sample collection is on an opportunistic basis and samples cannot always be collected immediately upon defection during field studies. Faeces that have been exposed to heat and moisturemay not accurately reflect levels of FGM. Our study exposed male (n=3) and female (n=3) Grevy's zebra (Equus grevyi) faeces to six environmental conditions to simulate a range of weather and seasonal patterns (temperate climate, high heat, high heat and rainfall, temperate climate and rainfall, high heat/temperate climate and freeze/thaw) over a period of five days. FGMs were quantified using an enzyme linked immunoassay. Results showed that environmental conditions do impact upon FGM levels over time, particularly in conditions that include high heat; however, regardless of environmental exposure, metabolites remain similar to baseline levels for up to 8 h. We recommend that the investigation of environmental factors on sample integrity should be carried out as a validatory step when planning studies involving FGM analysis in any species

Visual reinforcers designed for children with developmental disabilities

A library of visual reinforcers has been created to facilitate visual reinforcement audiometry (VRA) testing in children with developmental disabilities. The library includes 45 reinforcer sets – photos or videos grouped by a common theme – that were created based on commonly reported interests of children with developmental disabilities. Each reinforcer set contains a minimum of 20 unique photo or video files that can be download in two formats: one for commercially available VRA reinforcement systems and another for a custom setup. The library is freely available for download online under a Creative Commons License (Creative Commons Attribution-NonCommercial 4.0 International License). Use of these materials has the potential to improve behavioral testing outcomes for children with developmental disabilities, including children with restricted interests. Future research is needed to determine the effectiveness of implementing these materials in clinical settings

The ecological effects of livestock guarding dogs (LGDs) on target and non-target wildlife

Livestock guarding dogs (LGDs) are used across the world to reduce livestock depredation by free-ranging predatory wildlife. In doing so, they reduce the need for lethal predator control and are considered beneficial for conservation. However, LGDs might be perceived as predators by wildlife and induce a multitude of both positive and negative ecological effects. We conducted a literature review to evaluate the ecological effects of LGDs and found 56 publications reporting LGDs interacting with or affecting wildlife. Featuring in 77% of the publications, LGDs were widely reported to chase and kill wildlife, leading to species43 specific behavioural responses. A total of 80 species were affected by LGDs; 11 of which are listed as Near Threatened or higher on the IUCN Red List. Of the affected species, 78% were non-target species, suggesting that any benefits arising from the use of LGDs likely occur simultaneously with unintended ecological effects. However, the frequency of LGD-wildlife interactions and the magnitude of any resulting ecological effects have rarely been quantified. More empirical studies are therefore needed to determine the net ecological outcome of LGD use, thus ensuring that negative outcomes are minimised while benefiting both farmers and wildlife

Genetic analysis of the endangered Cleveland Bay horse: a century of breeding characterised by pedigree and microsatellite data

The Cleveland Bay horse is one of the oldest equines in the United Kingdom, with pedigree data going back almost 300 years. The studbook is essentially closed and because of this, there are concerns about loss of genetic variation across generations. The breed is one of five equine breeds listed as “critical” (<300 registered adult breeding females) by the UK Rare Breeds Survival Trust in their annual Watchlist. Due to their critically endangered status, the current breadth of their genetic diversity is of concern, and assessment of this can lead to improved breed management strategies. Herein, both genealogical and molecular methods are combined in order to assess founder representation, lineage, and allelic diversity. Data from 15 microsatellite loci from a reference population of 402 individuals determined a loss of 91% and 48% of stallion and dam lines, respectively. Only 3 ancestors determine 50% of the genome in the living population, with 70% of maternal lineage being derived from 3 founder females, and all paternal lineages traced back to a single founder stallion. Methods and theory are described in detail in order to demonstrate the scope of this analysis for wider conservation strategies. We quantitatively demonstrate the critical nature of the genetic resources within the breed and offer a perspective on implementing this data in considered breed management strategies

A Plasma Reactor for the Synthesis of High-Temperature Materials: Electro Thermal, Processing and Service Life Characteristics

The three-jet direct-flow plasma reactor with a channel diameter of 0.054 m was studied in terms of service life, thermal, technical, and functional capabilities. It was established that the near-optimal combination of thermal efficiency, required specific enthalpy of the plasma-forming gas and its mass flow rate is achieved at a reactor power of 150 kW. The bulk temperature of plasma flow over the rector of 12 gauges long varies within 5500±3200 K and the wall temperature within 1900±850 K, when a cylinder from zirconium dioxide of 0.005 m thick is used to thermally insulate the reactor. The specific electric power reaches a high of 1214 MW/m{3}. The rated service life of electrodes is 4700 hours for a copper anode and 111 hours for a tungsten cathode. The projected contamination of carbides and borides with elec-trode-erosion products doesn't exceed 0.0001% of copper and 0.00002% of tungsten

Livestock guarding dogs enable human-carnivore coexistence: first evidence of equivalent carnivore occupancy on guarded and unguarded farms

Livestock guarding dogs (LGDs) are advocated to reduce livestock depredation on agricultural lands. However, LGDs have been proposed as excluding carnivores from guarded farms; this study is the first to test this hypothesis in an African ecosystem. We investigated carnivore occupancy (black-backed jackal, leopard and brown hyaena) from 1029 camera-trap days (126 camera locations) in relation to the presence of LGDs and a range of habitat and land-use covariates across eight South African farms, five of which utilised an LGD. Models containing LGDs had little support in explaining leopard or black backed jackal occupancy, although LGD presence had a positive relationship with brown hyaena occupancy (β = 1.14, 95% CI = 0.05, 2.23). Leopard detection was positively related to the presence of black-backed jackals (β = 1.47, 95% CI = 0.18, 2.74) and sheep (β = 1.13, 95% CI = 0.14, 2.12), whilst black-backed jackal detection was negatively related to lures (β = -1.33, 95% CI = -2.00, -0.65) and positively related to the presence of brown hyaena (β = 0.90, 95% CI = 0.43, 1.40). Previous research in this LGD population has demonstrated the cessation of livestock depredation in 91% of cases, making dog ineffectiveness unlikely to explain their lack of influence on carnivore occupancy. Our results provide the first empirical evidence based on ecological data of the capacity for LGDs to promote human-carnivore coexistence in an African agricultural context, further validating the use of specialist guarding dogs as a conservation tool of benefit to both human and wildlife populations