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Topic:Horses
"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Factors affecting the ultrasonic properties of equine digital flexor tendons. The velocity, attenuation and apparent backscattering coefficient of 6-11-MHz ultrasound were measured in three orthogonal directions in equine deep digital flexor (DDF) and superficial digital flexor (SDF) tendons at 0 degree C. Ultrasonic measurements were examined for correlation with tendon water, collagen, DNA and glycosaminoglycans contents, determined by chemical analyses and with structure observed by scanning electron microscopy. The SDF tendon contained more water, more DNA (i.e., more cells), less collagen and less glycosaminoglycans and exhibited lower velocities and attenuations t...
Biomechanical effects of rocker-toed shoes in sound horses. In many Western European countries rocker-toed shoes are applied routinely in sound horses. This is in contrast to most Anglo-Saxon countries where rocker-toed shoes are used almost exclusively for corrective or orthopaedic shoeing. The purposes of rocker-toed shoes are to hasten or facilitate breakover, or to encourage breakover to occur at the centre of the toe. This study compares the biomechanical effects of rocker-toed shoes with standard flat shoes in twelve sound Dutch warmblood horses, using a modified CODA-3 gait analysis system and a force plate. The variables analysed were speed of ...
[Occurrence of Parascaris equorum in foals and adult horses under different breeding conditions]. Autopsies and analyses of faecal samples from working horses have shown common occurrence of ascarids in foals, whereas 19.6% of adult horses have been found infected. No influence of season on EPG in adult horses has been found. Study based on faecal samples from stud horses has shown that 5-6-month old animals were most susceptible to the infection. 50% of foals have been found infected in spite of deworming with the use of bezimidazole compounds. It has been stated that the proper dose of an anthelminthic is a basic problem in the control of ascarids.
Hyaluronan turnover in the synovial fluid in metacarpophalangeal–and middle carpal joints in standardbred horses. The biological turnover of hyaluronan (sodium hyaluronate) of different molecular weights (0.6 x 10(6) and 2.5 x 10(6) Daltons) was studied in the synovial fluid of the middle carpal and metacarpophalangeal joints of 6 clinically healthy Standardbred horses. The hyaluronan was radioactively labelled with 14C. The biological half-life (t1/2) was calculated from repeated synovial samples after injection of the labelled hyaluronan. The mean t1/2 in the metacarpophalangeal joints was 9.7 h for low molecular weight hyaluronan and 8.9 h for high molecular weight hyaluronan and in the middle carpal j...
Horses are sensitive to pictorial depth cues. In an attempt to demonstrate whether horses could make use of pictorial cues to depth, two were trained initially to make a relative-line-length discrimination between two lines placed one above the other. Psychophysical measurement of their discrimination thresholds showed that from a viewing distance of approximately 160 cm they could reliably distinguish a lower line of 10 cm from an upper one of 14 cm. In the second phase of the experiment, two lines of equal length were superimposed on a photograph of a set of railway tracks with many pictorial cues to depth, or a photograph of a pastoral...
Effects of storage on serum ionized calcium and pH from horses with normal and abnormal ionized calcium concentrations. It has been previously shown that Ca(I) concentration is stable in serum collected from healthy horses for 10 days if stored at 40 degrees C. This may not be true for horses with abnormal Ca(I) concentrations. Thus the stability of ionized calcium (Ca(I)) concentration and pH measurement in serum from horses with both normal and abnormal Ca(I) concentrations stored for various times at 40 degrees C and -10 degrees C was evaluated. Our results indicated that serum Ca(I) concentration was stable throughout 7 days of cold or frozen storage, after being received by the Clinical Chemistry Laborator...
Total replacement of the metatarsophalangeal joint in the horse. A single pilot study. In this paper the successful replacement of an equine metatarsophalangeal joint by a human total condylar knee prosthesis is reported. In the period of observation following implantation of the endoprosthesis the experimental animal showed almost no lameness when exercised at walk, bearing weight on the operated limb. Flexion and extension of the joint were markedly reduced. The clinical and histological observations clearly support further investigation into the equine metatarsophalangeal joint replacement by an endoprosthesis.
Micellar electrokinetic capillary chromatography combined with immunoaffinity chromatography for identification and determination of dexamethasone and flumethasone in equine urine. A capillary electrophoresis technique was developed for the separation of synthetic glucocorticoids and the determination of dexamethasone and flumethasone in horse urine. Pretreatment of the sample using a dexamethasone affinity column resulted in low background that enabled the authors to detect levels as low as 1.1 ng/mL and 2.7 ng/mL for dexamethasone and flumethasone in horse urine, respectively. The developed method was used to detect dexamethasone in horse urine samples after the injection of a therapeutic dose of dexamethasone for up to 12 hr postinjection. The optimum conditions for c...
Demonstration of three DRB loci in a domestic horse family. Single-strand conformational polymorphism (SSCP) gel electrophoresis and DNA sequencing were used to characterize the second exon of the horse DRB homologue as well as to identify eight new DRB alleles. The SSCP gels presented a complex pattern, with phenotypes exhibiting between 4 and 13 bands. The DRB SSCP patterns were studied for two families (6 to 13 bands per pattern). For both families, the patterns showed simple Mendelian inheritance. The polymerase chain reaction products from two individuals possessing homozygous major histocompatibility complex (MHC) alleles by descent were cloned a...
Effects of tendon grip technique (frozen versus unfrozen) on in vitro surface strain measurements of the equine deep digital flexor tendon. To determine effects of tendon grip technique on in vitro surface strain measurements of equine deep digital flexor tendon (DDFT) when loaded in tension. Methods: 12 hind limb DDFT from 8 adult horses (mean age, 9.8 years [range, 4.5 to 17 years]; mean body weight, 472 kg [range, 450 to 509 kg]), with no clinical evidence of hind limb lameness. Methods: After calibration, liquid mercury strain gauges were sutured to plantar surfaces of the tendons at distal (position 1), middle (position 2), and proximal (position 3) metatarsal regions. Each tendon was affixed to a materials testing machine (d...
Effects of subject velocity on ground reaction force measurements and stance times in clinically normal horses at the walk and trot. The objective of the study reported here was to evaluate the effects of changing velocity on stance time and ground reaction force (GRF) measurements in horses at the walk and trot. Methods: Force plate gait analysis was used to evaluate clinically normal horses at variable velocities. Ground reaction force measurements and stance times were recorded and compared. Methods: 12 adult horses. Methods: Data were obtained from 192 valid trials at the walk and 162 valid trials at the trot. Vertical, braking, and propulsive peak forces and impulses were measured. Pearson's correlation coefficients we...
Bioavailability of pivampicillin and ampicillin trihydrate administered as an oral paste in horses. Pivampicillin was administered as an oral paste to five healthy adult horses, and an oral paste with ampicillin trihydrate was administered to three horses. Pivampicillin was administered to both starved and fed horses, ampicillin trihydrate was administered to fed horses only. The dose of pivampicillin was 19.9 mg/kg, and the dose of ampicillin trihydrate was 17 mg/kg. Both doses are equivalent on a molecular basis to 15 mg/kg ampicillin. Ampicillin concentrations in plasma were determined up to 24 hours after administration. After administration of pivampicillin to starved and fed horses the...
Three cases of carcinoid in the equine nasal cavity and maxillary sinuses: histologic and immunohistochemical features. Three cases of carcinoid tumor in horses are described. The tumors originated from the maxillary sinuses and the retrobulbar region and caused exophthalmos. Histologically, they had a characteristic endocrine pattern and were argyrophilic with the Grimelius stain. All tumors contained reactivity for neuron-specific enolase and synaptophysin. Two of three tumors were reactive for both bovine and porcine chromogranin A. These immunohistochemical results confirm the neuroendocrine nature of these tumors. Neuroendocrine cells could not be detected in the nasal mucosa and maxillary sinuses of a nor...
Are kinematics of the walk related to the locomotion of a warmblood horse at the trot? In purchase examinations or at studbook selection sales the locomotor apparatus of horses is judged both at walk and trot. To evaluate whether kinematics of the walk are related to the locomotion at the trot, fore and hind limb movements of a group of 24 26-month-old warmbloods were recorded at walk and trot on a treadmill (1.6 and 4 m/s) using a modified CODA-3 gait analysis system. The intralimb coordination patterns at walk and trot were compared, and temporal and spatial variables of these gaits were related. Stride and stance durations (s) were shorter at the trot, while the stance distan...
Expression of major histocompatibility complex antigen and timing of invasion by equine chorionic girdle cells cultured on Matrigel. Chorionic girdle cells are a highly invasive subpopulation of trophoblastic cells of the horse conceptus that adhere to the uterine epithelium and begin to invade the endometrium on Days 34-36 (Day 0 = day of ovulation). Just prior to and during invasion (Days 32-36), chorionic girdle cells express high levels of major histocompatibility complex (MHC) I, but expression of this antigen decreases by Days 40-45 and is lost by Day 55. The mechanisms involved in the control of chorionic girdle cell invasion and altered MHCI expression over time are not known. The objective of this study, therefore,...
The effect of diagnostic regional nerve blocks in the fore limb on the locomotion of clinically sound horses. The practice of applying diagnostic nerve blocks relies on the assumption that the blocks in themselves do not alter the horse's gait. This assumption has recently been challenged. In the present paper a series of sequential nerve blocks (low palmar digital block, abaxial sesamoid block, high palmar block) was applied to clinically sound horses. Before and after each block the gait was clinically scored and Ground Reaction Forces (GRF) were measured. Clinical scoring did not change after any of the nerve blocks. None of the GRF variables changed significantly except for a slight alteration of ...
Lack of acid-resistant trypsin inhibitor in mare’s colostrum: short communication. Mare's colostrum was collected and examined for the presence of trypsin inhibitors. It was found to contain a low level of trypsin inhibitor which could be denatured by 2.5% trichloroacetic acid and, therefore, it clearly differs from the acid-resistant colostral inhibitor of Artiodactyla and Carnivora. This finding is exceptional for a species that concentrates IgG in the colostrum and whose newborn absorbs colostral proteins non-selectively by the gut. It appears that the presence of colostral trypsin inhibitor is not essential for the transmission of maternal immunity via the colostrum and ...
Relationship of plasma lactate production to cortisol release following completion of different types of sporting events in horses. Fifty-eight healthy horses were studied during five sporting events of various intensities and durations, namely show-jumping (n = 6), cross-country in a three-day event (n = 30), trotting races (n = 7), galloping races (n = 7) and endurance rides (n = 8). Venous blood samples were collected at rest and immediately after exercise and analysed for plasma cortisol (CORT) and lactate (LA) levels. The experimental procedure was the same throughout the investigation so as to permit a reliable comparison between the five types of exercise. The type of event significantly affected both the resting (p...
Equine infectious anemia virus replication is upregulated during differentiation of blood monocytes from acutely infected horses. Equine infectious anemia virus is a lentivirus that replicates in mature tissue macrophages of horses. Ponies were infected with equine infectious anemia virus. During febrile episodes, proviral DNA was detectable, but viral mRNA was not detectable. As cultured blood monocytes from these ponies differentiated into macrophages, viral expression was upregulated. In situ hybridization confirmed that viral transcription occurred in mature macrophages.
Effects of exercise intensity and environmental stress on indices of oxidative stress and iron homeostasis during exercise in the horse. The effects of prolonged variable-intensity and short-term high-intensity exercise on indices of oxidative stress and iron homeostasis were compared in six fit horses under cool [20 degrees C, 40% relative humidity (RH)] or hot/humid (30 degrees C, 80% RH) environmental conditions. The exercise protocols were designed to simulate equine competition, including racing (intense exercise) or the speed and endurance phase of a 3-day event (prolonged exercise). Increased plasma concentrations of lipid hydroperoxides and haemolysate concentrations of oxidised glutathione (GSSG) were measured within 3...
Effects of additional premedication on romifidine and ketamine anaesthesia in horses. The clinical and cardiorespiratory effects of premedication with acepromazine, butorphanol or diazepam in addition to romifidine before induction of anaesthesia with ketamine were studied in 6 horses on 4 random occasions. Administration of romifidine alone or in combination with butorphanol resulted in an increase in arterial blood pressure, accompanied by a significant decrease in heart rate with second-degree atrio-ventricular heart block. Induction of anaesthesia with ketamine returned the heart rate to baseline value, but the arterial blood pressure was significantly increased compared to...
Effects of aging on the endodontic system, reserve crown, and roots of equine mandibular cheek teeth. To document age-related changes in the morphology of the endodontic system, reserve crown, and roots of equine mandibular cheek teeth. Methods: Equine mandibular cheek teeth from horses of various ages were compared, using radiography, x-ray computed tomography, and histologic examinations. Methods: 48 right hemi-mandibles from horses 2 to 9 years old. Methods: Hemi-mandibles were radiographed, imaged by computed tomographic reconstruction, and reformatted. Histologic examination was used to identify and correlate tissue types. Results: Permanent mandibular cheek teeth of the horse, at the tim...
The diagnostic nerve block of the sesamoidean nerve: desensitized structures and possible clinical applications. The sesamoidean nerve branches from the palmar nerve and runs towards the proximal sesamoid bone. To study the structures innervated by this nerve, a technique for blocking it was developed. The effect of this nerve block was determined in ponies with an induced lameness located in the lateral proximal sesamoid bone (5 ponies) or in the distal part of the lateral branch of the suspensory ligament (5 ponies), and in 10 horses with clinical sesamoidosis. A lameness provoked by the implantation of an expansion plug in the proximal sesamoid bone could, to a large extent, be anaesthetized by a sesa...
[The history of neurectomy in horses with navicular disease]. The genetic predisposition to navicular disease is proven nowadays, but otherwise, etiology and pathogenesis are still unclear. Causal therapy isn't possible and because of the poor prognosis, neurectomy is still of bearing. This operation was performed already 200 years ago, but in the middle of the last century, critical voices have been raised in regard to the surgical procedure and its indication both for medical reasons and breeding. Clear instructions for exclusion of diseased animals from breeding are also older than one hundred years. These facts call for ethic considerations which con...
Osmolality of equine blastocyst fluid from day 11 to day 25 of pregnancy. Horse conceptuses collected between Day 11 and Day 18 of pregnancy float in isotonic media. To investigate this phenomenon, blastocyst fluids from 30 conceptuses from 13 mares were analysed for osmolality and for concentrations of Na+, Cl-, K+, glucose, urea and creatinine. In conceptuses from Group A, samples from Day 11 to Day 16 yielded the following results (mean +/- s.e.m.): osmolality, 121.4 +/- 1.5 mOsm kg-1; Na+, 11.0 +/- 2.2 mM; Cl-, 29.3 +/- 2.5 mM; K+, 26.2 +/- 2.6 mM; glucose, 0.6 +/- 0.1 mM; urea, 6.0 +/- 0.6 mM; creatinine, 9.6 +/- 1.1 microM. Between Day 16 and Day 25, the osmol...
A partially automated pretreatment module for routine analyses for seventeen non-steroid antiinflammatory drugs in race horses using gas chromatography/mass spectrometry. A partially automated module for the routine determination of illicit non-steroid antiinflammatory drugs (NSAIDs) in biological fluids from race horses was built, tested, refined, and shown to work. This pretreatment module retains 17 NSAIDs on an Amberlite XAD-2 column before back-elution derivatization with methyl iodide in acetonitrile. Methylated derivatives are manually injected into a gas chromatograph connected to a mass spectrometer. The quantification limits thus achieved are 50-100 ng/mL in 1 mL of urine or plasma. The proposed method is more expeditious than its manual liquid-liquid...
Rapid and quantitative analysis of bilirubin in equines by high-performance liquid chromatography. Rapid and quantitative analytical methods for bilirubin using high-performance liquid chromatography (HPLC) with UV detection were developed for samples from equines at a meat inspection site. Sharp HPLC peaks for bilirubins, unconjugated bilirubin (UCBL) and conjugated bilirubin (CBL), were obtained using a simple mobile phase of methanol:0.5 M Tris-HCl buffer (65:35, v/v, pH 7.4). A variable wavelength detector set at 450 nm, 0.01 AUFS and a recorder set at 4 cm/min were used for detection. Peaks for UCBL and CBL occurred at 7.1 min and 4.9 min, the lower limits of detection ranged between 0...
Collagen fibril diameter distributions in ligaments and tendons of the carpal region of the horse. Since horses bred for the racing industry are subject to rigorous training procedures there is a real need to understand how the stresses experienced by their tendons and ligaments in vivo relate to the major load-bearing elements-the collagen fibrils. Consequently, an age-related study has been made of the collagen fibril diameter distributions of nine ligaments in and around the equine carpus. This is the first stage of a larger study aimed at understanding the ultrastructural changes that occur as a result of exercise. Most of the ligaments showed a bimodal diameter distribution at maturity...
