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Topic:Field Study
Field studies involving horses are research investigations conducted in natural or semi-natural environments outside of laboratory settings. These studies aim to observe and analyze equine behavior, ecology, and physiology in real-world conditions. Field studies can encompass a wide range of topics, including grazing patterns, social interactions, habitat use, and the impact of environmental factors on horse health and welfare. Researchers employ various methodologies such as direct observation, GPS tracking, and non-invasive sampling to collect data. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of field studies in understanding equine behavior and ecology.
Effects of ketanserin on hypergranulation tissue formation, infection, and healing of equine lower limb wounds. The objective of this multicentre, randomized, controlled field study was to determine the efficacy of ketanserin gel in preventing exuberant granulation tissue formation (hypergranulation) and infection in equine lower limb wounds. Horses and ponies (n = 481) with naturally occurring wounds were randomized to either topical treatment with ketanserin gel (n = 242) or a positive control (Belgium, Germany: ethacridin lactate solution, n = 120; France, United Kingdom: malic, benzoic, and salicylic acid [MBS] cream, n = 119). Treatment continued until the wound healed (success), formed hypergranul...
Avian host preference by vectors of eastern equine encephalomyelitis virus. An important variable in the amplification and escape from the enzootic cycle of the arboviral encephalitides is the degree of contact between avian hosts and mosquito vectors. To analyze this interaction in detail, blood-fed mosquitoes that were confirmed vectors of eastern equine encephalomyelitis (EEE) virus were collected in 2002 from an enzootic site in central Alabama during the time this virus was actively transmitted. Avian-derived blood meals were identified to the species level of the host, and the proportion derived from each species was compared with the overall composition of the ...
Oral susceptibility of South African Culicoides species to live-attenuated serotype-specific vaccine strains of African horse sickness virus (AHSV). The oral susceptibility of livestock-associated South African Culicoides midges (Diptera: Ceratopogonidae) to infection with the tissue culture-attenuated vaccine strains of African horse sickness virus (AHSV) currently in use is reported. Field-collected Culicoides were fed on horse blood-virus mixtures each containing one of the seven serotype-specific vaccine strains of AHSV, namely serotypes 1, 2, 3, 4, 6, 7 and 8. The mean titres of virus in the bloodmeals for the seven vaccine strains were between 6.8 and 7.6 log10TCID50/mL. All females (n = 3262) that survived 10 days extrinsic incubati...
Seasonal dynamics of the Cayenne tick, Amblyomma cajennense on horses in Brazil. The population dynamics of all stages of the Cayenne tick, Amblyomma cajennense (Fabricius) (Acari: Ixodidae) on horses was evaluated over a period of 2 years in the district of Pedro Leopoldo, State of Minas Gerais, Brazil. Every 14 days, the left side of 20 horses was brushed for collection of immature stages; counts of adults were also undertaken. Infestation by larvae was detected from April to August, whereas nymphs were observed from June to October. Infestation by adults was detected throughout the year, and the highest population density occurred from September to March. The number of ...
Acquired resistance of horses to Amblyomma cajennense (Fabricius, 1787) ticks. Acquired immunity of horses to larvae, nymphs and adults of the Amblyomma cajennense tick was evaluated through three consecutive experimental infestations of tick-bite naïve hosts. Data from these infestations were compared to those from field-sensitized horses and donkeys. It was observed that tick-bite naïve horses developed a low level of resistance after two infestations as shown by a significant decrease in larval yield and a tendency for lower engorged weight of nymphs during third infestation. Ticks fed on field-sensitized horses had a similar biological performance to that observed ...
Speed of sound measurements of the third metacarpal bone in young exercising thoroughbred racehorses. The purpose of this longitudinal in-field study was to evaluate the influence of exercise, age, and gender on superficial cortical bone of the third metacarpal bone (MC III) in young Thoroughbreds by measuring speed of sound (SOS) values with an axial transmission technique (Omnisense, Sunlight Ltd, Israel). Both MC III of 75 racehorses, 2 to 4 years old, were monitored with SOS measurements in 5- to 7-week intervals during a 9- month physical exercise period. Medical data and training programs (slow gallop, canter, and high-speed work) of each horse were recorded. SOS measurements began befor...
Grazing of spotted locoweed (Astragalus lentiginosus) by cattle and horses in Arizona. Spotted locoweed (Astragalus lentiginosus var. diphysus) is a toxic, perennial plant that may, if sufficient precipitation occurs, dominate the herbaceous vegetation of pinyon-juniper woodlands on the Colorado Plateau. Six cow/calf pairs and four horses grazed a 20-ha pasture with dense patches of locoweed in eastern Arizona during spring 1998. Locoweed density was 0.7 plants/m2 in the pasture. Locoweed averaged 30.4% NDF and 18.4% CP. Concentrations of the locoweed toxin, swainsonine, fluctuated from 1.25 to 2 mg/g in locoweed. Horses ate more (P < 0.01) bites of locoweed than did cows (15...
Field test data on small strongyles in evaluation of activity of fenbendazole given once a day for 5 consecutive days to thoroughbred yearlings on two farms in Kentucky in 2002 and 2003. Fenbendazole (FBZ) suspension was administered intraorally at the dose rate of 7.0-10.3 mg/kg once a day for 5 consecutive days to 58 thoroughbred yearlings on two farms in central Kentucky in April, 2002. The average dose rates of drug given to groups of colts and fillies on each farm were 7.8-8.5 mg/kg. Only 3 of the yearlings had negative counts of strongyle eggs per gram of feces (EPGs) after treatment which was at 8.4, 8.7, or 9.4 mg/kg; the pretreatment EPG counts were low (10-30). Reduction of EPG values at the highest dose rates was 0% (at 9.5 mg/kg) and 78% (at 10.3 mg/kg). This study...
Evidence for a new field Culicoides vector of African horse sickness in South Africa. Between February and May 1998, approximately 100 horses died of African horse sickness (AHS) in the cooler, mountainous, central region of South Africa. On 14 affected farms, 156,875 Culicoides of 27 species were captured. C. imicola Kieffer, hitherto considered the only field vector for AHS virus (AHSV), constituted <1% of the total Culicoides captured, and was not found on 29% of the farms. In contrast, 65% of the Culicoides were C. bolitinos Meiswinkel, and was found on all farms. Five isolations of AHSV were made from C. bolitinos, and none from 18 other species of Culicoides (including C....
Efficacy of a paste formulation of omeprazole for the treatment of naturally occurring gastric ulcers in training standardbred racehorses in Canada. The efficacy of a paste formulation of the H+, K+, -ATPase inhibitor omeprazole was evaluated in standardbred racehorses for the treatment and prevention of gastric ulcers. Twenty standardbred racehorses in training, aged 2 to 9 years, were enrolled from 2 training centres in this field trial. Endoscopic examinations confirmed the presence of gastric ulcers in all horses, prior to allocation and treatment and on day 0. Lesions were scored on a scale of 0 to 3 (intact epithelium to extensive ulceration). Replicates were formed, based on training level and location. Within replicates, 1 horse wa...
A field study to estimate the prevalence of Trypanosoma equiperdum in Mongolian horses. From May to July 2000, a cross-sectional study was conducted to estimate the prevalence of Trypanosoma equiperdum in the horse population of the central province (Tuv aimag) of Mongolia. On average, four herds were selected from each of the 29 aimag subdivisions (119 herds). From each herd, 10 horses were sampled in proportion to sex and age categories in the respective herds (1190 horses). Sera from 1122 horses were analysed for T. equiperdum antibodies using two serological assays, the complement fixation test (CFT) and the enzyme-linked immunosorbent assay (ELISA). The crude estimate of the...
A non-lethal method for assessment of efficacy of antiparasitics against parasites in horses such as Anoplocephala perfoliata and Gasterophilus intestinalis. Sourcing of horses naturally infected with parasites such as Anoplocephala perfoliata and Gasterophilus intestinalis for antiparasitic efficacy slaughter studies is often difficult, expensive, and usually excessive numbers of animals must be slaughtered before significant data can be obtained. To overcome this problem a "Modified Critical Treatment Method" was developed. This method does not require the horses to be sacrificed, but relies on the collection and processing of all faecal material containing expelled parasites from test animals. Efficacy is assessed by comparing, in the same horse...
Mosquitoes captured in a horse-baited stable trap in southeast Louisiana. A mosquito study based on collections from horse-baited stable traps was conducted in 1993 and 1994 at 3 sites in geographically and ecologically distinct areas of St. Tammany Parish (southeastern Louisiana) to determine the major horse-feeding mosquito species that could be possible bridging and epidemic vectors of eastern equine encephalomyelitis virus. A total of 4,535 mosquitoes in 1993 and 23,906 in 1994 involving 26 species were collected, of which, depending on the site, Culex salinarius, Cx. (Melanoconion) spp., Aedes vexans, Psophora ferox, Coquillettidia perturbans, Anopheles quadrim...
VP2 gene phylogenetic characterization of field isolates of African horsesickness virus serotype 7 circulating in South Africa during the time of the 1999 African horsesickness outbreak in the Western Cape. We present the first VP2-gene phylogenetic analysis of African horsesickness (AHS) viruses within a serotype. Thirteen AHSV 7 isolates were obtained from cases that occurred in South Africa during 1998-1999, and three were historical AHSV 7 isolates. The goals were to start a database of isolates of known location and time of isolation and to determine if we could identify the origin of an AHS outbreak in the surveillance area in the Western Cape. We prepared full-length cDNA copies of the VP2-genes of the isolates. Nucleic acid sequence data of a 786 bp region was used to characterize the gen...
A field evaluation of PCR for the routine detection of Babesia equi in horses. We report on a study that evaluated the usefulness of PCR for the routine detection of Babesia equi in horses. The blood from a total of 105 horses comprising both sick and apparently healthy animals were examined for the presence of B. equi using both Wright-Giemsa-stained blood smears and PCR. Microscopic analysis of Giemsa-stained blood smears revealed 10/105 animals positive for Babesia, compared to 16/105 for the primary PCR and 36/105 for the nested PCR. Three of the 10 samples positive by Wright-Giemsa-stain were negative by PCR for B. equi. However, evidence is presented that these sam...
[Reliability of the glutaraldehyde test to measure gamma-globulin levels in foals and the use of this test to check colostrum intake of foals]. The glutaraldehyde coagulation test is a semi-quantitative test used to determine the gammaglobulin concentration in serum. The purpose of this study was to examine the reliability of the different modifications of this test by determining the sensitivity, specificity, positive and negative predictive value, and the prevalence of hypogammaglobulinemia in foals. The results of the glutaraldehyde coagulation test were compared with the serum gammaglobulin concentration as a reference value, determined by measuring total serum protein and the serum protein spectrum. It was concluded that the glut...
Field study of the efficacy of three types of nose net for the treatment of headshaking in horses. Thirty-six owners of seasonally headshaking horses took part in a trial to compare the effectiveness of three types of nose net, a traditional cylindrical net (full net) and two forms of larger mesh nets which cover only the nostrils and dorsorostral muzzle (half nets). Baseline data relating to the overall severity of the problem and 18 specific behaviours describing the nature of the problem were recorded on a check sheet by the owners. A within-subjects repeated measures design experiment, with each net used for a week before reassessment, was then used to assess the effect of the nets on t...
Occurrence of infectious upper respiratory tract disease and response to vaccination in horses on six sentinel premises in northern Colorado. Horses vaccinated against common agents of infectious upper respiratory disease (IURD) may not have detectable serum antibody and may not be protected from clinical disease. Objective: The objectives of this study were to 1) investigate the serological response of horses to vaccination against influenza virus (H3N8 and H7N7) and equine herpesviruses (EHV) in a field setting and 2) evaluate associations among vaccination status, serum antibody concentrations, and occurrences of IURD in monitored horses. Methods: In this study, horses on 6 Colorado premises were vaccinated parenterally against i...
Evaluation of the field application of PCR in the eradication of contagious equine metritis from Japan. The effectiveness of the polymerase chain reaction (PCR) as a field application test for the eradication of contagious equine metritis (CEM) was evaluated. Seven-thousands five-hundred and thirty-four genital swabs were collected from 4,026 Thoroughbred broodmares and stallions in Japan to test "high risk" horses as well as for general surveillance testing from 1998 to 2001. Bacterial isolation as well as PCR testing of original specimens and cultured specimens was performed for detection of Taylorella equigenitalis from genital swabs. As a result, T. equigenitalis was detected in 12 mares and...
Metabolic responses to submaximal field exercise tests and relationships with racing performance in pacing Standardbreds. This study was undertaken to invesigate the application of submaximal field tests in assessment of performance. A submaximal field exercise test consisting of 2 bouts of pacing for 1600 m, with 5 min rest or walking between runs was performed on Standardbred racehorses at 2 training centres (A and B). Performance indices were compiled for each horse: number of race starts, number of race wins, number of race placings (1, 2 or 3), and lifetime earnings. Regression analysis was conducted to describe the relationship between plasma lactate concentrations and speed for tests one, 2 and pooled resu...
Use of sentinel herds to study the epidemiology of vesicular stomatitis in the state of colorado. Approximately 20 sentinel premises in Colorado were visited quarterly during a 3-year prospective study to investigate the persistence of VS viruses in horses. A survey to assess management practices, health events, animal movements and environmental data was completed at each visit. Collection of serum samples and oral swabs along with a clinical examination of sentinel horses were performed at each visit. Serum samples were tested by 2 or more of 4 available serological tests. The data collected for two years (August 1998 to August 2000) are reported here. During this period there was seroco...
Neutralizing antibodies against vesicular stomatitis viruses (serotypes New Jersey and Indiana) in horses in Costa Rica. Serum samples were collected from domestic horses in 4 different regions of Costa Rica to detect antibodies against vesicular stomatitis viruses, serotypes New Jersey (VSV-NJ) and Indiana (VSV-IN). A total of 214 samples were tested by the virus neutralization test. The sampling regions were identified as low North Pacific dry area (1), low Middle Atlantic humid area (2), low South Pacific humid area (3), and the highlands (4). In region 1, 97.1% of horses were positive for VSV-NJ and 16.5% were positive for VSV-IN. The mean antibody titer and its standard deviation after logarithmic transform...
Porcine zona pellucida (PZP) immunocontraception of wild horses (Equus caballus) in Nevada: a 10 year study. Porcine zona pellucida (PZP) immunocontraception was investigated for possible use in free-roaming wild horses in the western USA. A protocol of two injections (3-4 weeks apart) of vaccine lasting 1 year was first used and a single-injection controlled-release vaccine of 1 year duration was developed and tested in the field. Studies of a presumptive vaccine of 2 year duration were initiated. The parameters of anti-PZP antibody titre response, pregnancy testing and offspring production were used, and PZP vaccine was found to provide up to 94% infertility in free-roaming wild mares. In addition,...
Area under the curve calculations as a tool to compare the efficacy of equine influenza vaccines–a retrospective analysis of three independent field trials. Using the area under the curve (AUC) concept as is commonly used in pharmaceutical bioequivalence studies, the bioequivalence of three equine influenza vaccines was demonstrated. A retrospective analysis was performed using this technique on data generated in three trials in which each of the three vaccines had been used. In total, data from 63 pony and horse foals were used. The AUC of the single radial hemolysis (SRH) titres against Influenza A/equi-1/Prague/56 (Pr/56), A/equi-2/Newmarket-1/93, and A/equi-2/Suffolk/89 (Suf/89) were calculated for each horse. It was concluded that calculation...
The classification of seven serotypes of equine encephalosis virus and the prevalence of homologous antibody in horses in South Africa. Selected isolates of equine encephalosis virus were shown to have comparable viral protein profiles and to represent seven distinct serotypes, based on cross-neutralization tests. Serotype-specific virus-neutralizing antibody in serum samples from horses confirmed the widespread occurrence of infection. The distribution and prevalence of individual serotypes however, varied considerably. Localised foci with an increased seasonal seroconversion in groups of horses to a specific serotype and the detection of an ongoing low level of infection from other serotypes within the population, confirmed ...
Age-related changes in lymphocyte subsets of quarter horse foals. To characterize changes in lymphocyte subsets over time in foals from birth to 18 weeks of age, accounting for differences among individuals, and to determine the effect of overnight storage of blood samples on foal lymphocyte subset concentrations. Methods: 8 healthy Quarter Horse foals from birth to 18 weeks of age. Methods: Blood samples were collected longitudinally from birth to 18 weeks of age and a CBC performed on each sample. The samples were stained for lymphocyte markers, either immediately or after overnight storage and analyzed by flow cytometry. Results: Total leukocytes, total l...
Conditioning taste aversions to locoweed (Oxytropis sericea) in horses. Locoweed (Oxytropis sericea) is a serious poisoning problem for horses grazing on infested rangelands in the western United States. Our objectives were to determine 1) whether lithium chloride or apomorphine would condition aversions to palatable foods, and at what doses, and 2) whether horses could be averted to fresh locoweed in a pen and grazing situation. Apomorphine was not an acceptable aversive agent because at the dose required to condition an aversion (> or = 0.17 mg/kg BW), apomorphine induced unacceptable behavioral effects. Lithium chloride given via stomach tube at 190 mg/kg BW...
Physiological variables measured under field conditions according to age and state of training in French Trotters. We hypothesised that the derived physiological variables V2 and V4 (velocity to achieve a blood lactate concentration of 2 and 4 mmol/l, respectively), HR2 and HR4 (the corresponding heart rate) and V200 (the velocity for a heart rate of 200 beats/min) would improve with training state and age, in French Trotters. A total of 194 French Trotters from one training establishment were followed for 6 years and 1105 standardised field exercise tests performed on a sand training track. The horses were divided into 6 age groups (from 1 to > or = 6 years) and 4 training groups (beginning, endurance tra...
Finite element analysis (FEA) as a model to predict effects of farriery on the equine hoof. A finite element (FE) hoof capsule was built as a small, symmetrical forelimb hoof on IDEAS* as a model for calculation and visualisation of stress and displacement of the equine hoof capsule. The model's loading was performed according to the suspension of the coffin bone within the hoof wall (pulling force) and over the sole and frog (compressing force) with a total of 3000 N. Restraints of the model's ground nodes and surface wall nodes were defined for simulation of 4 shoeing situations: a regular horseshoe, a horseshoe with a toe clip, a horseshoe with regular side clips and a horseshoe w...
Seasonality and relative abundance of Tabanidae (Diptera) captured on horses in the Pantanal, Brazil. Once a month, from June 1992 to May 1993, collections of tabanids on horse were conducted in the Nhecolândia, Pantanal State of Mato Grosso do Sul, Brazil. Tabanid catches using hand nets were conducted from sunrise to sunset at grassland and cerradão (dense savanna) habitats. A total of 3,442 tabanids from 21 species,12 genera, and 3 subfamilies were collected. Although species abundance varied seasonally depending on habitat, no habitat specificity was observed for the most abundant species. In the grassland, 1,625 (47.2%) tabanids belonging to 19 species were collected, while 1,817 (52.8%...
