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.
Ríha J, Minár J, Králík O, Krupa V.The adverse effect of blood-sucking dipterous insects (gadflies, gnats, black flies, midges) was determined and checked, as exerted on the working performance of draft horses working in forests; the possibilities of protecting horses with repellents were studied at the same time. The trial was conducted under field conditions in the territory of the Broumov Forest Establishment in the Náchod and Trutnov districts. A 10% water emulsion of the repellent, diethyltoluamide, was used; the horses were treated with the emulsion in a 24-hour interval. Over the seventy working days from the 1st of Jul...
Edwards GT.The stomachs of 448 horses from northern England and Wales were examined for Gasterophilus larvae, and 237 (52.7%) were found to be infected with G. intestinalis. Larvae were present in stomachs examined during each month of the year except August. Second instar larvae occurred from September through February and third instars were present from November through July. Adult fly activity began in August as indicated by the presence of eggs on horses. The life-cycle of G. intestinalis in northern England and Wales is outlined from the data presented. The mean instar burdens were 15.7 second and 3...
Horner GW, Hunter R.Two serologically unrelated adenoviruses were isolated from ill-thrifty young horses on a thoroughbred stud. The viruses differed in their cytopathic effects in cell culture and in their haemagglutination properties. A serological survey of horses in the northern half of the North Island showed the prevalence of precipitating antibodies against equine adenoviruses to be 39%.
Bryans JT, Allen GP.A chemically inactivated, adjuvanted vaccine prepared from a virulent strain of Equine herpesvirus I (EHV-I) was used to immunize pregnant Thoroughbred broodmares during a five-year field test designed to determine its safety and efficacy. Each mare in the vaccinated groups received 3 intramuscular injections of vaccine beginning immediately prior to and during the last half of pregnancy. Vaccine was injected at approximately 60-day intervals. The accumulated incidence of EHV-I abortions among vaccinated mares during the field trial period was 1.6/1000 as compared with an incidence of 6.8/1000...
Turner JW, Kirkpatrick JF.This field study of feral stallions in Montana and Idaho examines and correlates the seasonal pattern of plasma androgens and specific sociosexual behaviour and reports the effect of a long-acting androgenic steroid on this behaviour and on fertility. Plasma testosterone was measured by competitive protein binding assay in samples obtained by jugular venepuncture from captured animals. In samples taken from 34 sexually mature stallions in 6 different months during the year, a definite seasonal pattern in testosterone was present, with a peak in May (3.04 +/- 0.63 ng/ml) and a nadir in December...
Webel SK, Squires EL.The clinical effectiveness of the synthetic progestagen, altrenogest, was evaluated in field trials with 449 mares during the 1980 breeding season. An oral dose of 27 mg altrenogest was administered daily for 15 days. In the first trial treated mares were compared with controls, and in the second trial the effectiveness of treatment for prolonged or erratic spring oestrus was evaluated. Oestrus was suppressed in 94% of the treated mares in the first trial. The post-treatment response was related to the stage during the transition from winter anoestrus to the spring breeding season and degree o...
Burrows R, Denyer M, Goodridge D, Hamilton F.Experimental ponies developed signs of disease four days after the intranasal instillation of A/England 1/79 equine influenza virus and virus was recovered from the nasopharynx from the second to the ninth day. No significant antigenic difference was found between the virus and the prototype A/Miami 1/63 virus, using post infection ferret and chicken sera and post vaccination pony sera. No antigenic differences were found between four viruses isolated between January and July 1979, although some differences were found in their ability to detect haemagglutination inhibiting antibody in convales...
Herd RP, Miller TB, Gabel AA.The effectiveness of 1 pro-benzimidazole (pro-BZD) drug, 3 benzimidazole (BZD) drugs, and 3 non-benzimidazole (non-BZD) drugs in keeping fecal egg counts below 50 eggs per gram 2 and 4 weeks after treatment at 6-week intervals was compared in groups of brood mares and yearlings at 2 Standardbred farms. In a preliminary study (December 1978 to April 1979) as well as major study (April to November 1979), horses were kept in the same groups in the same areas. In the major study, treatments were arranged in a Latin square design. On farm 1, which had a history of repeated use of BZD drug since 196...
Clayton HM, Trawford AF.A field study was designed to investigate the re-establishment of patent lungworm infections in donkeys following an anthelmintic treatment regime which was effective against Dictyocaulus arnfieldi. In April 1979 faecal samples from 259 donkeys were examined and each animal classified as a negative, low positive or high positive excretor of lungworm larvae. During the summer the control group of 126 donkeys showed an increase in the number of excretors from 80 per cent in April to 91 per cent in October. At the same time there was a rise in the faecal larval output of individual animals so tha...
Pemberton DH, Thomas KW, Terry MJ.The prevalence of hypogammaglobulinaemia in 82 young foals was determined. Twelve foals were considered clinically abnormal at birth and ten died within two weeks. All of these foals were hypogammaglobulinaemic. Seven (10%) of the other 70 apparently normal foals were hypogammaglobulinaemic despite having suckled normally. Three of these foals developed significant disease and one died at one month of age. Rapid detection of foals with low serum immunoglobulin levels was achieved by adapting the zinc sulphate turbidity test to partially evacuated blood collection tubes. This permitted test to ...
Mirck MH.The use of trichlorfon as an anthelmintic in horses has increased since it was combined with mebendazole and febantel, and became commercially available as Telmin-trichlorfon and Rintal-plus respectively. Field studies showed that these combined preparations frequently gave rise to cases of poisoning. Mild to severe colic was observed up to six hours after treatment, diarrhoea and/or anorexia continuing to be present for one to six days after administration. The 'horse weight measurer' introduced by Janssen Pharmaceutica is not sufficiently accurate to prevent overdosage. It is advisable only ...
Ray AC, Post LO, Hurst JM, Edwards WC, Reagor JC.An analytical method for cantharidin, using high performance liquid chromatography, was applied to field specimens from horses and sheep with blister beetle (Epicauta lemniscata) poisoning. Stomach content and urine proved to be valuable aids in diagnosis. One incident of cantharidin toxicosis in ruminants (sheep) was confirmed.
Thomas KW, Pemberton DH.Components of plasma or serum, including immunoglobulins, were concentrated two-fold by freezing then collecting 40-50% of the initial volume during thawing. This concentrated plasma (or serum) was administered intravenously to treat hypogammaglobulinaemic foals and calves. An adaptation of this method suitable for field use is described.
Carpio MM, Iversen JO.Leptospira interrogans serotype pomona antibody titres of 1:100 or greater were detected in 12.8% of 408 adult horses from seven of eight sampled herds in Saskatchewan. The geographical distribution of the seropositive horses was widespread throughout the agricultural area of the province. The geographical distribution and the cumulative increase in prevalence with age suggested that serotype pomona is enzootic in the equine population of Saskatchewan.
Willoughby RA, McDonell WN.Pulmonary function tests in horses are in the early stages of development and there will be a limit in the range of tests available since those requiring patient cooperation cannot be conducted in animals. Some tests such as blood gas analysis, A-aDo2 and delta Ppl measurements could presently be used to a greater extent under field conditions. Others that require expensive equipment and considerable technical assistance will be limited to the larger referral type veterinary clinics until the time is reached when there is adequate information to select those procedures that give a reasonable c...
Slocombe JO.A study was initiated to determine the prevalence of tapeworms in horses in Southern Ontario and to investigate the efficacy of pyrantel pamoate, niclosamide and mebendazole. Fecal samples were taken from 580 horses of various breeds, ages and sexes in 24 locations and Anoplocephala perfoliata was found in 13.6%. This was regarded as a minimum, the true rate being probably significantly higher and the reasons for this are discussed. A brief review of the life cycle and effects of tapeworms in horses and a comparison of two flotation techniques for the diagnosis of A. perfoliata eggs in feces i...
Baker EF, Sasso DR, Maness K, Prichard WD, Parker RL.In 1971, more than 370 horses in south Texas were studied with respect to their clinical, virologic, and neutralizing antibody responses to vaccination with Venezuelan equine encephalomyelitis (VEE) strain TC-83. This study confirms reported findings that the vaccine used in the 1971 epizootic in the lower Rio Grande Valley of Texas was safe and efficacious. Vaccinal virus viremia titers were generally below the postulated infection threshold of epizootic vectors. In general, reactions to the vaccine were minimal and transient, with no observed abortions or deaths attributable to use of the va...
Slocombe JO, Cote JF.The anthelmintic canbendazole (CBZ), adminis-
tered in several formulations to horses in critical
trials, has been shown to have high effcacy
against intestinal nematodes (3, 4, 6). There are
two reports of field trials with CBZ (2, 5), and
although a large number of horses were involved,
the efficacies reported were for a restricted
number of nematodes. Recently, CBZ paste was
administered to horses in another field trial and
the findings on rxdatability, safety and efficacy
against a wide range of nematodes are presented.
Powell DG.An outbreak of contagious equine metritis that occurred on stud farms in the Newmarket area during 1977 is described. A Gram-negative coccobacillus was isolated from field cases and the disease was reproduced experimentally by inoculating a pure culture of the organism through the cervix of clean pony mares. Natural spread of the disease occurred by venereal transmission and following the handling, examination or teasing of infected mares. Bacteriological screening of the genital tract of mares and stallions before covering plus stricter standards of hygiene on the stud farms have been recomme...
Jones RH, Hayes RO, Potter HW, Francy DB.A survey of biting flies in the southwestern United States resulted in the recovery of 34 species as they attacked equines. The geographic distribution of each species at 15 sites and the abundance of attacking flies were used to determine that 22 species commonly attack equines. Culicoides variipennis (Coquillett) was the most common species collected; it was recovered at 12 sites and comprised the highest percentage (29.8%) of the total survey catch for all species collected. The next 2 most common species were Psorophora columbiae (Dyar & Knab) and Aedes vexans (Meigen). C. variipennis was ...
Honstein RN, Monty DE.Field investigations were conducted under natural environmental conditions to determine the physiologic responses of rested, hydrated horses (Equus caballus) to the very hot, dry weather characteristic of the summer season in southern Arizona. The emphasis of the investigation was placed on those thermoregulatory mechanisms which are involved in the maintenance of homoiothermy. Rectal temperature of the horses studied remained relatively stable throughout the day, during both cool and hot weather seasons. However, when horses were exposed to hot summer temperatures, rectal temperature (heat st...
Moore RM, Moulthrop JI, Sather GE, Holmes CL, Parker RL.Field studies were conducted in 1972 to determine the immunization status of equines along the Mexico, Arizona, and New Mexico borders. Interviews with horse owners were conducted along roads selected at random in the counties of Santa Cruz and Yuma, Ariz., and in Dona Ana County, N. Mex. At least 450 horse owners in each county were asked about the vaccination status of their animals, and information was taken on 1,260 animals. Blood specimens were obtained from every third equine, regardless of stated vaccination status, and tested for the presence of Venezuelan equine encephalitis (VEE), we...
Powell DG, Burrows R, Spooner P, Mumford J, Thomson G.The observations reported in this paper were obtained as part of a long term surveillance programme designed to monitor the efficacy of influenza vaccines and study the prevalence of influenza and other respiratory viruses among horses in Britain. Inactivated influenza vaccines were found to be effective in protecting horses from disease caused by influenza A/equine-1 but were less successful in protecting horses against influenza A/equine-2. The paper presents the clinical, epidemiological virological and serological findings obtained between 1971 and 1976.
Gay CC, McCarthy M, Reynolds WT, Carter J.A method using the Doppler ultrasound principle for indirect determination of arterial blood pressure in the horse is described. The method is simple and suitable for field situations. Validation studies show that systolic and diastolic blood pressure measurements bear a close relationship to true values obtained by direct measurement.
Kienapfel K, Link Y, König V Borstel U.Much controversy exists among riders, and in particular among those practicing dressage, regarding what can be considered an "appropriate" Head-Neck-Position (HNP). The objective was to assess the prevalence of different HNPs in the field, the behavioural reactions of horses during warm-up and competition rides in relation to HNP and the relation between HNP and marks achieved in the competition. Horses (n = 171) were selected during dressage competitions according to their HNP (3 categories based on the degree of flexion), and their behaviour was recorded during 3 minutes each of riding i...
Kuhar U, Završnik J, Toplak I, Malovrh T.In 2009, a surprisingly high number of animals seropositive for equine infectious anaemia virus (EIAV; 26 horses from 13 farms) were detected in Slovenia. Objective: To develop a polymerase chain reaction (PCR) assay for the detection of the proviral nucleic acid, to phylogenetically characterise the Slovenian EIAV strains and to investigate whether transmission in utero occurred. Methods: Cross-sectional clinical study. Methods: In total, 26 horses (including 2 foals and 4 pregnant mares) and 4 fetuses were examined in this study. A PCR assay using the EIAV F1 and EIAV R1 primers was designed...
Woodie JB, Ducharme NG, Hackett RP, Erb HN, Mitchell LM, Soderholm LV.Dorsal displacement of the soft palate (DDSP) is a common condition in racehorses for which various surgical treatments are often performed. In light of recent findings that suggested the position of the larynx may influence the occurrence of DDSP, we investigated whether a noninvasive mean of affecting the position of the larynx could be effective in the management of DDSP. Objective: An external device (laryngohyoid support; LHS) positioning the larynx in a more rostral and dorsal location and preventing caudal displacement of the basihyoid bone would be effective in preventing DDSP during s...
Munsters CC, van Iwaarden A, van Weeren R, Sloet van Oldruitenborgh-Oosterbaan MM.Regular exercise testing in Warmblood sport horses may, as in racing, potentially help to characterise fitness indices in different disciplines and at various competition levels and assist in understanding when a horse is 'fit to compete'. In this review an overview is given of the current state of the art of exercise testing in the Olympic disciplines of eventing, show jumping and dressage, and areas for further development are defined. In event horses, a simple four-step incremental exercise test measuring heart rate (HR), lactate concentration (LA) and velocity (V) is most often used. In dr...
Douglas-Hamilton DH, Osol R, Osol G, Driscoll D, Noble H.A field trial of artificial insemination in horses with transproted, chilled semen was conducted using a specially designed container which permitted a controlled, slow initial rate of cooling (-0.3 degrees C/min) and maintenance of a final temperature of 4 degrees -6 degrees C for more than 36 hrs. Forty-six mares in 23 states were inseminated with semen from three German Warmblood stallions standing at stud in Hamilton, Massachusetts. A third-cycle conception rate of 91% was obtained.
Herholz C, Kopp C, Wenger M, Mathis A, Wägeli S, Roth N.Female tabanid flies (Diptera: Tabanidae) can be a serious nuisance for horses because of their painful bites during blood feeding. They also play a primary role in mechanical transmission of a lentivirus causing Equine Infectious Anemia (EIA), a virus that has spread within Europe in recent years. According to the European law for products intended for use as a repellent on horses (recreational and sport horses), a field test is mandatory to demonstrate sufficient repellency of such a substance against the specific target fly species, but currently no agreed protocols are available for testin...
Lyons ET, Tolliver SC, Drudge JH, Stamper S, Swerczek TW, Granstrom DE.Critical tests (91) were done between 1977 and 1992 in Shetland ponies to evaluate drug susceptibility and population dynamics (present paper) of endoparasites. The test ponies, most less than 1 year old, were from a herd where older animals were treated every 8 weeks initially with cambendazole (CBZ) (1974-1978) and then with oxibendazole (OBZ) (1978-1992). Previous field test data (1974-1992) on older ponies in the breeding herd indicated the presence of benzimidazole (BZ) resistant small strongyles. Data on population dynamics from the present critical tests indicated that 28 species of sma...
Howell PG, Nurton JP, Nel D, Lourens CW, Guthrie AJ.Cohorts of yearlings were sampled over a period of 6 years in a retrospective serological survey to establish the annual prevalence of serotype specific antibody to equine encephalosis virus on Thoroughbred stud farms distributed within defined geographical regions of South Africa. Seasonal seroprevalence varied between 3.6% and 34.7%, revealing both single and multiple serotype infections in an individual yearling. During the course of this study serotypes 1 and 6 were most frequently and extensively identified while the remaining serotypes 2, 3, 4, 5 and 7 were all identified as sporadic and...
Labruna MB, Amaku M.The present study evaluated the engorgement and drop-off rhythms of Anocentor nitens females feeding on horses. Drop-off rhythm was evaluated at 6h-intervals (06:00, 12:00, 18:00, and 00:00 h) on horses held in stalls or in a pasture. A new method of marking feeding female ticks (the bowknot technique) was developed to evaluate ticks on horses in pasture that attached to different parts of the horse's body. This technique was highly successful, indicating no significant interference on tick engorgement rate or final tick weight, length and reproductive capability. Horses held in the pasture du...
Rasch K, Schoon HA, Sieme H, Klug E.The aim of this field study was to examine the influence of the uterotonic substance oxytocin in 2 different therapeutic dosages of 15 and 25 i.u., respectively on the uterine drainage of oestrous mares and on their fertility. In addition endometrial biopsies of mares with and without intrauterine fluid accumulations around the time of ovulation were evaluated histomorphologically regarding the aetiology of susceptibility to uterine infection. A population of 59 Hanoverian Warmblood mares was used in this study. The mares were divided into Group A (mares with intrauterine fluid accumulations [...
Bazzano M, Giudice E, Rizzo M, Congiu F, Zumbo A, Arfuso F, Di Pietro S, Bruschetta D, Piccione G.The aim of this study was to investigate whether a combined global positioning system (GPS)/heart rate (HR) monitoring system is a valuable tool to assess, step by step, the physiological response of HR and its relationship with speed in healthy horses competing in an official show jumping class. Six mares performing a standardised warm-up and jumping course were monitored using a HR/GPS device. Venous blood lactate (BL), assessed before and after exercise, showed a significant increase (P = 0.0004) following the physical effort. One-way analysis of variance (ANOVA) showed significant changes ...
Brocard P, Pfister K.The combined drug Mebendazole plus Trichlorfon (Telmin plus Trichlorfon, Janssen Pharmaceutica, Beerse/Belgium) has been tested in a field trial against naturally acquired Gasterophilus spp. infestations in horses. 44 foals (1 to 1.5 years old, 350-450 kg body-weight) originating from different endemic areas of Switzerland, have been randomly allocated to two groups as follows: 28 foals were treated with Mebendazole plus Trichlorfon, 16 animals served as untreated controls. The drug (paste) was administered and dosed according to the user's instruction. Macroscopic examinations of the digestiv...
Landuyt J, Delbeke FT, Debackere M.The plasma concentrations of phenylbutazone (PBZ) and its major metabolites, oxyphenbutazone (OPBZ) and gamma-OH-phenylbutazone (OHPBZ) were determined for up to 72 h in six horses, following intravenous (i.v.) and intramuscular (i.m.) administration of 4 g phenylbutazone, 20 ml Phenylarthrite Ventoquinol (Vetoquinol Spécialités Pharmaceutiques Vétérinaires, Magny-Vernois, 70200 Lure, France). After i.v. dosing the plasma disposition was best described by a two-compartment open model. The hydroxylated metabolites OPBZ and OHPBZ were present in detectable concentrations for 72 h and 48 h, r...
Harðardóttir H, Murison PJ, Blissitt K, Olason S, Clutton RE.Ketamine at 2.2 mg/kg given i.v. is often used to induce anaesthesia for surgical procedures in horses under field conditions. Commonly, additional doses are needed to complete the surgery. We hypothesised that surgical conditions would be improved when 5 mg/kg of ketamine was used to induce anaesthesia, while induction and recovery qualities would not differ from those when 2.2 mg/kg ketamine was used. Objective: To compare the anaesthetic effects of two ketamine doses (5 and 2.2 mg/kg) during field anaesthesia for castration of horses. Methods: Prospective, randomised, blinded, clinical stud...
von Teichman BF, Dungu B, Smit TK.The polyvalent African horsesickness (AHS) attenuated live virus (AHS-ALV) vaccine produced at Onderstepoort Biological Products incorporates 7 of the 9 known serotypes circulating in southern Africa. Serological cross-reaction has been shown in vitro to Serotypes 5 and 9 by Serotypes 8 and 6 respectively, but the degree of in vivo cross-protection between these serotypes in vaccinated horses has not previously been reported. Due to the increasing incidence of AHS Serotypes 5 and 9 in the field, over the last 3-4 seasons of AHS in South Africa, and the absence of Serotypes 5 and 9 in the AHS-A...
Mellor PS, Boned J, Hamblin C, Graham S.This paper describes the first isolations of African horse sickness virus (AHSV) from insects in Spain. Seven isolations of AHSV serotype 4 were made; four from Culicoides imicola a known vector of the virus elsewhere, two from mixed pools of Culicoides species not including C. imicola and one from blood engorged mosquitoes. Three further isolations of AHSV serotype 4 were also made from horses kept adjacent to the insect collecting sites. This work presents the first definitive identification of the vectors of AHSV in Spain during the 1987, 88 and 89 epizootics. Suggestions are also made conc...
Rohdich N, Zschiesche E, Heckeroth A, Wilhelm C, Leendertse I, Thomas E.A multicentre field study was conducted in accordance with VICH Guideline on Good Clinical Practice (VICH 2000) to confirm the efficacy and safety of a new formulation of cefquinome for the treatment of naturally occurring severe bacterial infections and septicaemia in foals. Thirty-nine foals suffering from severe bacterial infections (such as pneumonia, gastro-enteritis, arthritis, omphalitis, or wound infections) or acute septicaemia were treated twice daily with the test product (1 mg cefquinome/kg body weight) intravenously for three days and then intramuscularly for three to 11 days. Inv...
Caston SS.Care of equine wounds in the field can be a challenging endeavor. Many times, wound care is complicated by chronicity or by prior inappropriate care in addition to the great degree of tissue trauma that occurred when the horse was wounded. Recognizing involvement of synovial structures, loss of skin, and damage to bone are critical in the initial examination of wounds and will guide future care. Education of clients is also important in that preparing them for possible outcomes during healing may help improve compliance and proper treatment of wound. Owners and trainers often perform much of t...
Vaidyanathan R, Edman JD.To estimate human exposure to potential vectors of eastern equine encephalomyelitis (EEE) virus, we compared collections of putative EEE virus vectors from human biting collections with collections from CDC, AB (American Biophysics), and New Jersey light traps and resting boxes in enzootic/epidemic foci of EEE virus in southeastern Massachusetts. Human biting collections caught significantly more host-seeking females than resting boxes or unbaited light traps (P < 0.05). Regression analysis of human biting collections to AB traps supplemented with CO2 could predict 60-70% of the actual human b...
Mitchell CJ, Darsie RF, Monath TP, Sabattini MS, Daffner J.A large net trap was used to sample mosquito populations attracted to horses at three sites each in Santa Fe and Rio Negro Provinces, Argentina, during the austral summer of 1984. These provinces, as well as others in Argentina, were affected by a severe epizootic of western equine encephalitis (WEE) during 1982-83. Totals of 2,752 and 6,929 mosquitoes were collected in Santa Fe and Rio Negro Provinces during five and three trap nights, respectively. Culex mosquitoes of the subgenus Culex were predominant (45.8% of total) in the Santa Fe collections, although Aedes albifasciatus also was preva...
Weaver RW, Entry JA, Graves A.Livestock are known contributors to stream pollution. Numbers of fecal streptococci and Escherichia coli in manure naturally deposited by livestock in the field are needed for activities related to bacterial source tracking and determining maximum daily bacterial loading of streams. We measured populations of fecal streptococci and E. coli in fresh and dry manure from cattle (Bos taurus L.), horses (Equus caballus L.), and sheep (Ovis aires L.) on farms in southern Idaho. Populations of indicator bacteria in dry manure were often as high as that in fresh manure from horse and sheep. There was ...
Molini U, Zaccaria G, Kandiwa E, Mushonga B, Khaiseb S, Ntahonshikira C, Chiwome B, Baines I, Madzingira O, Savini G, D'Alterio N.African horse sickness (AHS) is a non-contagious viral disease of horses and other equids caused by an arbovirus belonging to the Reoviridae family and genus Orbivirus. AHS is an endemic disease that is responsible for the death of a high number of horses every year in Namibia. At present, there is no information on the prevalence and distribution of AHS virus (AHSV) serotypes in the different regions of Namibia. Therefore, this survey aimed to fill this knowledge gap by investigating the AHSV seroprevalence in Namibian donkeys. Methods: A total of 260 blood samples (20 samples for each region...
Sudia WD, McLean RG, Newhouse VF, Johnston JG, Miller DL, Trevino H, Bowen GS, Sather G.Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies. Am J Epidemiol 101:36-50, 1975.-In June 1971, epidemic Venezuelan equine encephalitis (VEE) invaded the lower Rio Grande Valley in south Texas. The Boca Chica area of Cameron County was selected as a study site to investigate vertebrate involvement in the natural cycle of epidemic VEE on the basis of considerable evidence of VEE virus activity there in equines, humans, and mosquito vectors. Only one VEE virus isolation was made from 4739 wild and domestic non-equine vertebrates, although numerous equine...
Allen KJ, Franklin SH.To date there is no information on the comparison of the more recently documented technique of performing endoscopy during ridden exercise in the field, with the more traditional method of endoscopy during high-speed treadmill exercise. Objective: To compare the results of upper respiratory tract endoscopy in UK Thoroughbred racehorses performed during ridden exercise in the field with those obtained during exercise on the treadmill. Methods: A direct comparison was undertaken in 4 horses whereby both procedures were performed in the same horse within 10 days of each other. An indirect compari...
Lin HC, Wallace SS, Robbins RL, Harrison IW, Thurmon JC.In 4 mares suffering from dystocia, general anesthesia was induced with xylazine (1.1 mg/kg, IV) and ketamine (2.2 mg/kg, IV) and maintained with continuous intravenous infusion of ketamine (2 mg/ml), xylazine (0.5 mg/ml) and guaifenesin (50 mg/ml) in 1 L of 5% dextrose. The duration of the procedure of these mares were 40, 45, 180, and 35 minutes, respectively. For procedures required more than 1 hour (Mare 3), the dose of ketamine and xylazine in the mixture was reduced to 1 mg/ml and 0.25 mg/ml, respectively. Average infusion rate of the mixture used to maintain anesthesia for each mare was...
Buhl R, Nissen SD, Winther MLK, Poulsen SK, Hopster-Iversen C, Jespersen T, Sanders P, Carstensen H, Hesselkilde EM.Limited information is available on paroxysmal atrial fibrillation (PAF) in the horse. Indeed, undiagnosed PAF could result in poor performance. Due to the intermittent occurrence, PAF is difficult to diagnose. However, implanting a small ECG device (implantable loop recorder, ILR) subcutaneously, allows the continuous and automatic detection of PAF. Objective: The aim was to investigate the potential of ILRs as a tool for diagnosing PAF in horses with poor performance. Methods: Prospective field study. Methods: Twelve racing Standardbred trotters with intermittent reduced performance (mean ag...
Behnke T, Street P, Davies S, Ouyang JQ, Sedinger JS.Non-native ungulate grazing has negatively impacted native species across the globe, leading to massive loss of biodiversity and ecosystem services. Despite their pervasiveness, interactions between non-native grazers and native species are not fully understood. We often observe declines in demography or survival of these native species, but lack understanding about the mechanisms underlying these declines. Physiological stress represents one mechanism of (mal)adaptation, but data are sparse. We investigated glucocorticoid levels in a native avian herbivore exposed to different intensities of ...
Ramos ICDN, Ramos RADN, Lima VFS, Giannelli A, López IYT, Alves LC.The FLOTAC technique represents a highly sensitive method for the isolation of oocysts, eggs, and larvae of parasites in faeces. This assay could be used for detecting free-living stages of nematodes in the pasture but no attempt has been assessed so far. Therefore, the performance of FLOTAC technique for isolating infective larvae of nematodes in the environment was investigated and compared with the spontaneous sedimentation (SST) and centrifugal sedimentation (CST) techniques. The study was conducted in a horse farm located in northeastern Brazil, where the occurrence of strongyle larvae ha...
Tischmacher A, Wilford S, Allen K, Mitchell RD, Parkin T, Denoix JM.The objective of this retrospective study was to assess the safety and efficacy of a slow IV administration of 1mg/kg tiludronate in a large number of horses. Each horse that received at least one tiludronate-based treatment between 2006 and August 2019 at Virginia Equine Imaging or Fairfield Equine was included in the study. Concomitant medical treatments, preliminary nonsteroidal anti-inflammatory drug injection and potential side effects were recorded after each administration. Horses for which follow-up was available over 1 year were subject to clinical evolution assessment via lameness gr...
Bisanzio D, Giacobini M, Bertolotti L, Mosca A, Balbo L, Kitron U, Vazquez-Prokopec GM.West Nile Virus (WNV) transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority defined a surveillance plan to detect WNV circulation in birds, horses and mosquitoes. By applying spatial statistical analysi...
