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.
Marlin DJ, Schroter RC, White SL, Maykuth P, Matthesen G, Mills PC, Waran N, Harris P.The aims of the present field-based study were to investigate changes in fit horses undergoing acclimatisation to a hot humid environment and to provide data on which to base recommendations for safe transport and acclimatisation. Six horses (age 7-12 years) were flown from Europe to Atlanta and underwent a 16 day period of acclimatisation. Exercise conditions during acclimatisation (wet bulb globe temperature index 27.6+/-0.0 [mean +/- s.e.]) were more thermally stressful compared with the European climate from which the horses had come (22.0+/-1.8, P<0.001). Following the flight, weight l...
Mercier P, Chick B, Alves-Branco F, White CR.Eighty horses were involved in a comparative, controlled, and randomised field study conducted in Australia and Brazil. This study was undertaken to address the duration of efficacy (by faecal egg count reduction) of four anthelmintic pastes and to measure the time required between treatments on horses naturally infected by gastrointestinal nematodes. The treatment interval was based on the egg reappearance period (ERP), defined as "the period after treatment when horses have reached a positive egg count equal or superior to 200 eggs per gram (epg) of faeces". Horses were ranked according to p...
Lyons ET, Tolliver SC, Collins SS, Drudge JH.Research carried out during the last 4 years (1996-1999) of an 11-year study of the prevalence of internal parasites naturally transmitted to horse foals born on the same pasture on a farm in central Kentucky is presented here. Horses in this herd were not treated with any antiparasitic compound for over 20 years except for a replacement stallion in 1994. A total of 22 species, including 12 species of small strongyles, were recovered in the 4-year period. Transmission patterns of all species (n=35) of endoparasites recovered are compared for the 11-year study. Some of the changes were an incre...
Battsetseg B, Xuan X, Ikadai H, Bautista JL, Byambaa B, Boldbaatar D, Battur B, Battsetseg G, Batsukh Z, Igarashi I, Nagasawa H, Mikami T, Fujisaki K.Ticks play an important role in human and veterinary medicine particularly due to their ability to transmit protozoan pathogens. In this study we have demonstrated that polymerase chain reaction (PCR) and nested PCR methods enabled detection of Babesia caballi and Babesia equi in field isolates of Dermacentor nuttalli adult ticks from Mongolia. Primers specific for 218 bp fragment merozoite antigen 1 (EMA-1) gene of B. equi successfully amplified products from all samples of D. nuttalli adult ticks while primers for the 430 bp fragment product from BC48 gene of B. caballi amplified products fr...
Sentsui H, Inoshima Y, Murakami K, Akashi H, Purevtseren B, Pagmajav O, Sugiura T.Cross reactivity of equine infectious anemia virus (EIAV) antigen prepared using a recombinant baculovirus containing the p26 gene of strain P337-V70 was examined by the agar gel immunodiffusion (AGID) test and enzyme-linked immunosorbent assay (ELISA). Serum samples serially collected from 13 horses experimentally infected with six different EIAV strains (two or three horses per strain) were subjected to the test. Positive reactions were observed in the AGID test and ELISA before or soon after the first feverish period and continued persistently in most of the horses. The results with recombi...
Cullinane A, Weld J, Osborne M, Nelly M, Mcbride C, Walsh C.The purpose of these studies was to examine the response of Thoroughbred foals and yearlings to different influenza vaccines and vaccination regimes. The horses' antibody levels against haemagglutinin, an established correlate of protection were measured by haemagglutination inhibition. The first study investigated the extent to which maternal antibodies interfered with the humoral response to a subunit vaccine. The findings suggest that repeat vaccination in the face of maternal antibodies may induce tolerance as defined by serological testing. The second study compared the immune response el...
Davies JA, Schwalbach LM.The efficacy of ivermectin, fenbendazole, pyrantel pamoate and doramectin was evaluated under field conditions at 2 sites in the Free State Province of South Africa. The study involved 25 horses at each site, divided into 5 groups of equal size. Ivermectin, fenbendazole and pyrantel pamoate were administered orally at doses of 0.2, 10 and 19 mg/kg respectively. Doramectin was administered by intramuscular injection at a dose of 0.2 mg/kg. Treatment efficacy was based on the mean faecal egg count reduction 14 days post treatment. At site A a faecal egg count reduction of 100% was found after tr...
Fuller A, Maloney SK, Kamerman PR, Mitchell G, Mitchell D.We used implanted miniature data loggers to measure brain and arterial blood temperatures in three free-ranging zebras (Equus burchelli) in their natural habitat, every 5 min for 9 days. The animals experienced globe temperatures exceeding 40 C, and radiant heat load of about 1000 W m-2. Arterial blood exhibited a moderate amplitude (1.7 C) nychthemeral rhythm, with an acrophase at 19.00 h and a nadir late in the morning, at 10.00 h. Brain temperature consistently exceeded blood temperature, on average by 0.2-0.4 C, and changes in brain temperature closely tracked changes in blood temperature....
Behn C, Bostedt H.Under field conditions, the diagnosis of foal's diseases relies almost exclusively on the physical examination. As the signs of illness in the equine neonate are frequently vage and non-localizing, the diagnosis of diseases may be problematic. This often causes misinterpretations and leads to ineffective prophylaxis and treatment. The purpose of this study was to evaluate the usefulness of diagnostic ultrasonography of the foal's abdomen under field conditions to provide an optimized technique and to describe the normal findings. Diagnostic ultrasonography of the abdomen was performed after ob...
Traub-Dargatz JL, Garber LP, Fedorka-Cray PJ, Ladely S, Ferris KE.To estimate prevalence of fecal shedding of Salmonella spp among horses in the US horse population and prevalence of Salmonella spp in grain or other concentrate used as horse feed on equine operations in the United States. Methods: Cross-sectional survey. Methods: Horses on 972 operations in 28 states. Methods: Fecal samples were collected from horses resident at each operation. Only a single sample was collected from any individual horse; number of horses from which samples were collected on each operation was determined on the basis of number of horses on the operation. A single sample of g...
Davie AL, Evans DJ.The associations between velocity during a standardized, submaximal 800-m exercise test and blood lactate concentration after exercise were investigated in Thoroughbred racehorses on sand and grass racetracks. Predicted lactate concentrations for each horse's exercise test velocity were calculated from the line of best fit derived from results at each racetrack. The repeatability of the differences between the measured and predicted blood lactate response to exercise was also investigated. Exercise tests were conducted at speeds ranging from 12.8 to 16.6 m/s. The variability of velocity within...
Borges LM, Oliveira PR, Ribeiro MF.Anocentor nitens is a widespread ectoparasite of horses in Brazil. A study of the seasonal dynamics of the parasitic phase of this tick was made by regular census of engorging females (>/=4mm) on free-ranging horses, fortnightly from July 1995 to July 1997, at Pedro Leopoldo, Minas Gerais. Twenty horses were divided into four groups of five animals per group, each having a similar mix of resistant and less resistant animals, based on initial infestation. Every 2 weeks, one of the groups, in sequence, was treated with an acaricide to prevent excessive infestations, and female ticks were cens...
MacAllister CG, Sifferman RL, McClure SR, White GW, Vatistas NJ, Holste JE, Ericcson GF, Cox JL.A multicentre, blinded, randomised complete-block, field trial was conducted with 140 horses and foals age 4 weeks-28 years to determine if omeprazole paste is effective and safe in promoting healing of spontaneous gastric ulcers under a variety of field conditions and in different breeds and ages of horses. Horses in the study had gastric ulceration as determined by gastroscopy and were divided into replicates of 4 or 5 animals. One horse in each replicate was assigned randomly to receive an empty omeprazole syringe (sham-dosed control) and the remaining horses received omeprazole paste once ...
Newton JR, Townsend HG, Wood JL, Sinclair R, Hannant D, Mumford JA.Field outbreaks of influenza that occurred in vaccinated Thoroughbred racehorses in Newmarket in 1995 and 1996 were investigated by nucleoprotein ELISA and serology. Investigations showed that serum levels of vaccine-induced single radial haemolysis (SRH) antibody correlated closely with protective immunity against equine influenza and were consistent with observations made in previous experimental studies using nebulised aerosol challenge. In the second part of this study, antibody levels stimulated by vaccination were investigated to examine probable protection in high risk groups, such as y...
Kobayashi M, Kuribara K, Amada A.The purpose of this investigation was to study, under field conditions, the usefulness of an incremental exercise test to measure V200 (running velocity [V] at heart rate HR[ of 200 beats/min) for evaluation of training effects in the young Thoroughbred. Five to 112 two-year-old Thoroughbreds were used over 4 years to investigate the correlation between HR and V, the influence of the track and rider's weight to V200, reproducibility of V200 and the changes of V200 as training progresses. The high correlation coefficient between HR and V, and V200 were obtained in horses that exercised smoothly...
Clausen PH, Gebreselassie G, Abditcho S, Mehlitz D, Staak C.A field study of horses was conducted in the province of Bale, Ethiopian highlands. A rapid questionnaire analysis indicated that dourine, known as "Dirressa", is a major health problem of equines in this area. A total of 121 horses suspected of dourine were examined by use of clinical, parasitological, serological and DNA based techniques. Incoordination of hindlegs (76%), swelling of external genitalia (48.8%) and emaciation (39.7%) were the most common clinical signs observed. Using the haematocrit centrifugation technique (HCT), no trypanosomes were detected in blood, genital washes or tis...
Silvina Fernández A, Henningsen E, Larsen M, Nansen P, Grønvold J, Søndergaard J.An experiment was carried out in 1997 to test the efficacy of an isolate of the microfungus Duddingtonia flagrans against free-living stages of horse strongyles under conditions in the field and to assess the eventual effect of the fungus on the normal degradation of faeces. Faecal pats were made from faeces of a naturally strongyle infected horse, which had been fed fungal material at a dose level of 106 fungal unit/kg bwt. Control pats without fungi were made from faeces collected from the same animal just before being fed fungi. Faecal cultures set up for both groups of faeces to monitor th...
Higuchi T, Arakawa T, Hashikura S, Inui T, Senba H, Takai S.The effect on foals of prophylactic administration of hyperimmune plasma to prevent R. equi infection was investigated on three farms at which R. equi infection was endemic. Sixteen foals between 10 and 39 days of age were intravenously given 1-21 of hyperimmune plasma. ELISA antibody titres against R. equi were significantly increased and maintained at high levels for over 30 days in most of the recipient foals. The prevalence of R. equi infection was 6.3% (1/16) in the foals that received the immune plasma, and 26.3% (5/19) in the control foals not given the immune plasma on the three farms....
Mohr E, Krzywanek H, Pinkowski W.Monitoring training by measuring blood lactate content is a well-known procedure in sports physiology. Because of the difficulties in standardizing a test procedure in field studies, this method is fraught with considerable problems when applying it to race horses. The aim of the present study was to develop a test procedure which is able to give evidence about the training state of different race horses after nonidentical test-loads. Under almost identical environmental conditions, the level of blood lactate was determined in five trotters which were kept in training. Immediately after the si...
Hargreaves BJ, Kronfeld DS, Naylor JR.Thermoregulation may limit exercise performance under hot and humid conditions. This study compared heart rate (HR), respiratory rate (RR), rectal temperature (Tr), packed cell volume (PCV) and total plasma protein concentration (TPP) during a submaximal incremental field exercise test under high vs. low ambient temperature and relative humidity. Ten horses were tested 3 times in summer (July) and 3 times in autumn (September). Heart rate was measured continuously, the other variables at rest and immediately after 4 min at 3.5, 4.5 and 7.0 m/s, separated by 3 min rest intervals, and after 5 an...
Khalil AM, Murakami N.For the past 12 years, a study was conducted in the Misaki area (southern Kyushu Island, Japan) to investigate young males form new harems, how they acquire the mares and the factors affecting the process of new harem formation. Young males formed new harems between the ages of 3.8 and 7.6 yr, and 93% of these new harem groups were formed at the beginning of the breeding season. The most common way (87%) for young males to form a new harem was by acquiring wandering mares which had separated from their groups, whereas 13% stole unstable mares from established bands. The fact that all young mal...
Morley PS, Townsend HG, Bogdan JR, Haines DM.To evaluate efficacy of a commercial vaccine for prevention of infectious upper respiratory tract disease (IURD) caused by equine influenza virus. Methods: Double-masked, randomized, controlled field trial. Methods: 462 horses stabled at a Thoroughbred racetrack. Methods: Vaccine or saline solution placebo was administered 4 times in the population at 6-week intervals. The vaccine contained 3 strains of inactivated influenza virus, and inactivated equine herpesvirus type 4. Horses received 1 or 2 doses of vaccine or placebo prior to onset of a natural influenza epidemic, and were examined 5 d/...
Brandstetter J, Stanek C, Hinterhofer C.The use of handmade particulate reinforced alloy horseshoes (MMC metal matrix composites) was tested in a field study on 15 riding and draught horses. All horseshoes have been tempered after having been manually forged and tested concerning their surface imperfection. Forging temperature ranged between 350 degrees and 420 degrees C. Horseshoes in series A consisted of particulate reinforced wrought alloy (22% Al2O3 in alloy matrix). 11 shoeing periods with a duration of mean = 49.7 days (sd = 13.6) were evaluated. Horseshoes in series B consisted of particulate reinforced foundry alloy (20% Si...
Bader H, Röhrsheim C, Koene M, Meinecke B.Investigations in different species including the horse have demonstrated that prostaglandin F2 alpha (PGF2 alpha) is involved in initiating uterine contractions occurring during mating and artificial insemination (A.I.). Uterine contractions play an important role with respect to the sperm transport within the female genital tract. The objective of the present investigation was to evaluate whether the administration of PGF2 alpha (Dinoprost) synchronously to A.I. could have a positive effect on the pregnancy rate in mares. A field study including 346 warmblood-mares (age two to 20 years) belo...
Mazan MR, Hoffman AM, Manjerovic N.To compare response of horses to histamine bronchoprovocation (HBP), using total respiratory resistance (Rrs) measured by forced oscillatory mechanics (FOM) with dynamic compliance (Cdyn) and pulmonary resistance (RL) measured by the esophageal balloon method. Methods: 10 horses with various degrees of airway reactivity. Methods: The 2 methods for measuring airway responses to HBP were performed on separate days. Endpoints compared were increase of 150 or 200% of baseline Rrs (PC150Rrs, PC200Rrs) and to 150% of baseline RL (PC150RL) or decrease to 65% of baseline Cdyn (PC65Cdyn). Frequency dep...
Osterman Lind E, Höglund J, Ljungström BL, Nilsson O, Uggla A.Faecal egg counts were performed during the first quarter of 1995 on samples from 1183 horses of varying breeds, ages and gender on 110 farms in 3 regions of Sweden. The majority of the horses had been treated with ivermectin or pyrantel when stabled the previous autumn. The risk of reinfection with strongyles between treatment and sampling was therefore considered to be minimal. Consequently, the results reflect primarily the occurrence of worms originating from inhibited strongyle larvae refractory to anthelmintic treatment. A total of 922 (78%) individuals were found to shed strongyle eggs,...
Lang J, Simanjuntak GH, Soerjosembodo S, Koesharyono C.WHO's reference protocol for post-exposure rabies vaccination advises five intramuscular injections on days 0, 3, 7, 14, and 30; in addition, rabies immunoglobulins (RIG) must be given to serious cases of exposure (grade III severity). Some studies indicate that these immunoglobulins suppress the immunogenicity of rabies vaccine when administered according to an alternative protocol of four injections (2-1-1) on days 0, 7, and 21, which was therefore not recommended for grade III exposures. To test this effect, we conducted a multicentre study in Indonesia using three groups of subjects. One g...
Mebarki M, Kaidi R, Azizi A, Basbaci M.Ultrasonographic fetal sexing is of utmost economic importance for horse breeders. Relatively, a few studies have been conducted to determine fetal sex in mare using transrectal Doppler ultrasound. This study aimed to compare two sexing techniques, two-dimensional (2D) mode and color Doppler ultrasonography. Methods: The study was conducted on 39 mares under field conditions. Examinations were performed using the ultrasonic model device (Medison SonoAce Pico, South Korea), equipped with real-time 3-7 MHz convex multifrequency transducer. Fetal sex diagnosis was carried out in two periods of pr...
Razavizadeh AT, Mashhadi AG, Paphan AA.An observational field study was performed on a well-know purebred horses in Iran (Khozestan-Arab horse). The study was conducted on 105 apparently healthy horses. To find the prevalence of cardiac dysrhythmias in different sexes and ages, the horses were divided into 2 sexes (63 females and 42 males) and three age groups (0-4, 4-8, > 8 years old). After taking the history and performing clinical examination, ECG was obtained on a base apex lead system with the paper speed of 25 mm sec(-1) and sensitivity of 10 or 5 mm mv(-1) at rest. The electrocardiograms were evaluated according to the crit...
Clulow JR, Buss H, Sieme H, Rodger JA, Cawdell-Smith AJ, Evans G, Rath D, Morris LH, Maxwell WM.In the 2004/2005 breeding season, the fertility of sex-sorted (SS) and non-sorted (NS) frozen stallion spermatozoa from two Hannovarian stallions was compared. A hysteroscopic insemination technique [Morris, L.H., Tiplady, C., Allen, W.R., 2003a. Pregnancy rates in mares after a single fixed time hysteroscopic insemination of low numbers of frozen-thawed spermatozoa onto the uterotubal junction. Equine Vet. J. 35, 197-201] was used to deposit low doses (6, 13 or 25 x 10(6) frozen-thawed SS or NS spermatozoa) onto the utero-tubal junction at 32 or 38 h after the administration of Chorulon (2500...
Salas-Romero J, Gomez-Cabrera K, Molento MB, Lyons ET, Delgado A, González L, Arenal A, Nielsen MK.Equine cyathostomin parasites are ubiquitous in grazing horses and have been shown to cause severe inflammatory disease in the large intestine of horses. Decades of intensive anthelmintic therapy have led to widespread anthelmintic resistance in cyathostomins across the world. In Cuba, no anthelmintic products are formulated and sold for equine usage and little is known about anthelmintic efficacy of ruminant and swine formulations used. A strongyle fecal egg count reduction test was used to assess the efficacy of a liquid formulation of ivermectin labelled for use in swine, ruminants and carn...
Roethlisberger-Holm K.Recording of intratracheal pressure during exercise as a method for evaluating upper airway obstruction in the horse has previously been carried out on the treadmill. In the present study the method was applied to normal horses, outdoors under field conditions, to assess its usefulness for analysis of respiratory problems mainly occurring under racing conditions. The horses examined performed a standardized exercise test during which the intratracheal pressure was recorded with a tape recorder receiving amplified signals from a transducer connected to a percutaneously inserted intratracheal ca...
Roelfstra L, Betschart B, Pfister K.In a study on the seasonal dynamics of the gastro-intestinal nematode egg production in horses, one breeding farm also revealed a particularly high prevalence of Anoplocephala spp. infection. Consequently, this farm was chosen for analysing the seasonal pattern of the tapeworm egg excretion over a one year period in order to establish the most favourable periods for an appropriate and successful cestocidal treatment. The seasonal analysis showed a significantly higher (p < 0.05) Anoplocephala spp. egg excretion between July and October, i.e. during the second part of the grazing period. This r...
Silvina Fernández A, Henningsen E, Larsen M, Nansen P, Grønvold J, Søndergaard J.An experiment was carried out in 1997 to test the efficacy of an isolate of the microfungus Duddingtonia flagrans against free-living stages of horse strongyles under conditions in the field and to assess the eventual effect of the fungus on the normal degradation of faeces. Faecal pats were made from faeces of a naturally strongyle infected horse, which had been fed fungal material at a dose level of 106 fungal unit/kg bwt. Control pats without fungi were made from faeces collected from the same animal just before being fed fungi. Faecal cultures set up for both groups of faeces to monitor th...
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...
Nakazawa M, Isayama Y, Kashiwazaki M, Yasui T.A protein antigen that reacted in the agar gel diffusion (AGD) test and which had equi factor(s) activity, was partially purified from the culture supernatant of Rhodococcus equi by successive column chromatography on diethylaminoethyl cellulose and Sepharose 4B. Employing a standard foal serum, the concentration of this antigen was adjusted for the AGD test. Optimal dilutions of the antigen reacted in the AGD test with sera from foals naturally infected with serologically different R. equi. The antigen prepared was considered suitable for use in field surveys of R. equi infection. Accordingly...
Gibb Z, Grupen CG, Maxwell WM, Morris LH.The fertility of sex-sorted, cryopreserved stallion sperm must be improved for the sex-sorting technology to be applied commercially. Objective: To optimise the conditions used to liquid store stallion sperm prior to sex-sorting and assess the fertility of sperm following sex-sorting and cryopreservation. Methods: Both in vitro experiment and randomised controlled trial in healthy, client-owned mares. Methods: Stallion ejaculates (n = 9) were diluted in either a skimmed milk (KMT) or BSA (I-BSA) based media to 25 × 106 sperm/ml directly (+SP25) or washed to remove seminal plasma and diluted t...
Lopes-Pereira CM, Harun M, Schmidtova D, Timane I, Mabasso M, Otto F, Bogin E.Adapting the concept of "bed-side" patient analysis, the Boehringer-Mannheim Reflotron was evaluated for its possible use in veterinary medicine under outdoor-field conditions. Horse blood was analysed with the Cobas Bio analyzer, and indoor and outdoor analyses were also performed with the Reflotron. All values showed close agreement with no significant differences. Good correlation coefficients (r values around 0.9000) were also seen between all methods used. The Reflotron was operated under outdoor-field conditions by using, whenever available, an on-farm electricity source, or a gas operat...
Aboashia FA, Alatrag F, Elmarimi A.Hematological and biochemical values are widely used in veterinary clinics for disease prognosis, nutritional and therapeutic monitoring, as well as in understanding the disease process in farm animals, including equines. This study aims to assess the alterations in hematological and biochemical parameters in pure Arabian horses infested with internal parasites. Samples of feces and blood were collected from 20 adult mares. Fecal samples were proceeded by flotation test. The blood samples were analyzed for hematological and biochemical parameters to determine their means ± standard error (M Â...
Sobral GG, Neto OCG, da Silva AM, Carneiro GF.The aim of the present study is to evaluate the correlation between the total protein measured by an optical refractometer and the concentration of IgG by radial immunodiffusion (RID) to determine the performance of the optical refractometer to diagnose the failure of passive transfer of immunity (FPTI) in 12-hour-old foals. Blood was collected from foals (n = 30) 12 hours after birth. A study was carried out to measure the serum IgG concentration by RID test and measure total protein (TP) by optical refractometer. The correlation coefficient was measured between the TP concentration and the...
Guhl A, Lindner A, von Wittke P.Eight thoroughbred horses, trained for racing competition, were subjected to a standardised incremental speed test to determine the relationship between their blood lactate concentrations and running speed. Between 14 days before and 14 days after completing the standardised exercise test, the horses were timed for runs of 2000 to 6000 m. The blood lactate concentration after each run was measured and compared with the blood lactate concentration predicted from the individual horse's blood lactate-running speed relationship curve determined from the standardised exercise test. The relationship...
Cock G, Blakeney Z, Hernandez JA, DeNotta S.Atlantoaxial (AA) cerebrospinal fluid (CSF) collection in standing horses utilizes the controlled narcotic morphine, thereby limiting feasibility in field practice settings. Objective: To compare AA CSF collection time and reaction scores in horses sedated with morphine-containing and opioid-free sedation protocols: detomidine + morphine (DM), detomidine + xylazine (DX), detomidine + detomidine (DD), detomidine alone (D0); To develop a novel method for assessing sedation in standing horses using open-source motion-tracking software. Methods: Six healthy adult horses. Methods: Randomi...
Shupe JL, Christofferson PV, Olson AE, Allred ES, Hurst RL.Teeth from cattle, sheep, and horses that ingested various fluoride intakes and teeth from field studies of these species plus deer, elk, and bison were examined for abnormalities. Approximately 99,000 animals in 322 herds were examined for fluorosis. From field studies, 988 cattle of various ages and with different degrees of dental fluorosis were slaughtered and necropsied. The severity of fluoride-induced mottling, hypoplasia, and abnormal abrasion of paired permanent incisor teeth was correlated with abrasion of premolar and molar (cheek) teeth that form and mineralize at approximately the...
Finan SA, Lamkin EL, McKinnon AO.To investigate the comparative efficacy of BioRelease Deslorelin® (BRD) and Ovuplant® for induction of ovulation in cyclic mares in Australia. Methods: Ovarian follicular activity of 60 mares for a total of 95 cycles was monitored by ultrasonography until they developed a follicle ≥30 mm and a uterine oedema pattern of 3. Mares were then randomly allocated to one of three treatment groups: (1) treatment with 1.25 mg BRD, (2) a single Ovuplant pellet or (3) 1 mL compound sodium lactate control. Follicular activity was monitored with ultrasonography every 12 h until ovulation was detec...
Jeawon SS, Katz LM, Galvin NP, Fogarty UM, Duggan VE.Although umbilical cord blood gas analysis is considered the best way to assess in utero oxygenation in human neonates, there is limited evaluation of this method in equine neonatology. Our objectives were to assess the practicality of obtaining umbilical cord blood gas samples in the field and to determine umbilical cord arterial and venous blood gas reference intervals (RI) for healthy, newborn foals. Thoroughbred foals >320 days gestation from healthy mares with uneventful pregnancies at one stud farm were evaluated. All parturitions were observed, with paired umbilical arterial and venous ...
Belotta AF, Mayer MN, Waldner CL, Robinson K, Sidhu N, Carmalt J, Bell CD, Koehncke NK.The objective of this study was to report observed radiation safety practices among equine workers using portable X-ray units at 3 veterinary practices in Canada. Practice 1 was comprised of equine field service workers from an academic institution, whereas Practices 2 and 3 were comprised of workers from private equine referral practices. Out of 2969 exposure-worker observations, protective aprons were worn for > 99% (2968/2969), thyroid shields for 87% (2584/2969), and eyeglasses for 10% (310/2969). The cassette was held by hand for 97% (1078/1114) of observations, and the X-ray unit was ...
Pusterla N, Naranatt P, Swadia H, Winfield L, Hartwig A, Barnum S, Mendonsa E.The introduction of microfluidic card technology has opened the field for rapid point-of-care (POC) molecular assays, including fecal and environmental Salmonella spp. testing. The purpose of this study was to evaluate a novel POC PCR assay for the detection of Salmonella spp. in feces and environmental samples. A total of 143 fecal samples and 132 environmental samples were collected for POC PCR Salmonella spp. testing as well as qPCR testing. Each sample was inoculated into selenite broth and incubated for 18 to 24 hours. For the POC PCR assay, 14 μl of selenite broth were mixed with 126 μ...
Machin J, Duer W, Maylin G, Fenger C, Wilson D, Ivey M, Berthold B, Allison S, Tobin T.Methylprednisolone (MP) acetate is a commonly used corticosteroid for suppression of inflammation in synovial structures in horses. Its use is often regulated in equine sports by plasma MP concentrations. Objective: To describe variability in MP plasma concentrations after MP acetate injection in different synovial structures and with co-administration with hyaluronic acid (HA). Methods: Field study in actively racing horses in three disciplines (Thoroughbred, Standardbred and Quarter Horse). Methods: Seventy-six horses (15 Thoroughbreds, 20 Standardbreds and 41 Quarter Horses) were included i...
Kilcoyne I, Nieto JE.For the equine veterinarian, orthopedic emergencies are a common occurrence in clinical practice, with traumatic wounds of the distal limb and penetrating injuries of the hoof being some of the most common medical conditions to affect horses. Intravenous regional limb perfusion is a technique widely used for the treatment of orthopedic infections in horses. The objectives of this review are to discuss some of the clinical applications for this treatment modality in the field and to review the technique for the practitioner.
Scully CM, Lee RL, Pielstick L, Medlock J, Patton KM, Collins GH, Kutzler MA.Free-roaming horse (Equus caballus) management is a complex issue incorporating social, economic, emotional, political, and environmental factors. Currently, few proven field techniques exist for managing free-roaming horse population growth, which can reach 20-25% annually. Although there are several strategies available for sterilizing mares when managing free-roaming horse populations, surgical vasectomy is the only method used in the field for stallions. Some managers believe that surgically vasectomizing dominant stallions would have significant effects on reducing horse populations. Howe...
Lyons ET, Drudge JH, Tolliver SC, Swerczek TW, Stamper S, Granstrom DE.Studies in a band of ponies harboring Population S benzimidazole-resistant small strongyles were initiated in 1974 and have continued for 18 years. Treatment (bimonthly) was with cambendazole for the first 4 years and with oxibendazole (OBZ) for the next 14 years. Data on the first 10 years have been published. The present investigation includes the last 8 years (4 October 1984-11 September 1992), which are the seventh through fourteenth years, of treatment with OBZ. Pre- and posttreatment mean counts of strongyle eggs (epg) and larvae (lpg) per gram of feces were determined biweekly during th...
Smith R, Chaffin MK, Cohen ND, Martens RJ.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...
Hewson J, Arroyo LG.Evaluation of the upper and lower respiratory tract of horses requires strategic selection of possible diagnostic tests based on location of suspected pathologic lesions and purpose of testing and must also include consideration of patient status. This article discusses the various diagnostic modalities that may be applied to the respiratory system of horses under field conditions, indications for use, and aspects of sample collection, handling, and laboratory processing that can impact test results and ultimately a successful diagnosis in cases of respiratory disease.
Dawson K.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...
Becht JL, Page EH, Morter RL, Boon GD, Thacker HL.A series of modified (field) tests were compared to a crossmatch between mare and foal for their reliability in predicting neonatal isoerythrolysis (NI) in eight foals born to experimentally alloimmunized mares. In the field tests, mare's serum, plasma and colostrum were combined with foal erythrocytes washed by a modified procedure to determine which combination was the best predictor of impending NI. A consistent grading system for agglutination and hemolysis was employed. The field tests using mare's plasma demonstrated less agglutination and hemolysis than tests where serum was employed. I...
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...
Horsington J, Hartley CA, Gilkerson JR.Respiratory infections are a major burden in the performance horse industry. Equine rhinitis B virus (ERBV) has been isolated from horses displaying clinical respiratory disease, and ERBV-neutralizing antibodies have been detected in 50-80% of horses in reported surveys. Current ERBV isolation and detection methods may underestimate the number of ERBV-positive animals and do not identify multiple serotype infections. The aim of the current study was to develop a serotyping ERBV antibody-detection enzyme-linked immunosorbent assay (ELISA) and examine the seroprevalence of ERBV in a group of Aus...
