Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Semrad SD, Moore JN.Thromboxane A2 may play a major role in circulatory shock. In some species, thromboxane synthetase inhibitors have a beneficial effect on shock induced by endotoxin, trauma, sepsis and administration of arachidonate. In some shock models, however, results with thromboxane synthetase inhibitors have been conflicting. The effect of UK-38,485, a selective thromboxane inhibitor, was evaluated in ponies injected with endotoxin intraperitoneally. Four groups of ponies were used to compare the effects of endotoxin alone, UK-38,485 alone, treatment with UK-38,485 before endotoxin challenge and treatme...
Doran RE, White NA, Allen D.Four adult horses and 3 foals with middle phalangeal fractures were treated by arthrodesis of the proximal interphalangeal joint, using a bone plate. Six of the 7 horses survived greater than 2 years; 2 of the 6 horses had intermittent lameness after hard work, and 4 horses didn't have evidence of lameness. The use of a bone plate for arthrodesis of the proximal interphalangeal joint was a successful treatment alternative for middle phalangeal fractures in horses.
Clarke AF, Madelin T.This paper describes and compares three techniques of categorisation of hay, straw and other feeds and beddings collected from stables. A hand-held sampler was used to categorise samples according to the presence of plant material, fungal spores and dust mites. An Andersen sampler was used to categorise samples according to the thermotolerances of fungi and actinomycetes. An aerodynamic particle sizer was used to categorise samples according to respirable particle release rates. The highest burden of respirable particles was associated with the presence of thermophilic and thermotolerant actin...
Schumacher J, Honnas C, Smith B.Primary paranasal sinusitis complicated by inspissated exudate within the ventral conchal sinus was diagnosed in five horses. Clinical signs included a unilateral, foul-smelling, mucopurulent nasal exudate of 2 to 7 months' duration. Two of the horses had partial nasal obstruction from distortion of the ventral concha. Radiographs of the skull showed a mass of soft tissue density dorsal to the roots of the superior third and fourth or fourth and fifth cheek teeth. Treatment included bone flap maxillary sinusotomy with exposure of the ventral nasal concha and removal of inspissated exudate. Res...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Latex was injected under pressure into bronchial and pulmonary arteries of the inflated lungs of Thoroughbreds and transverse sections taken to calculate the area of lesions resulting from exercise-induced pulmonary haemorrhage. Extensive areas of dense brown haemosiderin varying from 0 to 45 per cent of total lung volume were identified, predominantly in the dorsocaudal lungfields. Bronchial arterial proliferation appeared to have replaced the pulmonary supply in affected areas of the lung. Closely associated with the staining and bronchial arterialisation, there was widespread small airway d...
Dyer DC, Hsu WH, Lloyd WE.Twenty healthy ponies were given i.v. 1.1 mg/kg of xylazine from 2 manufacturers and the pharmacokinetic parameters calculated from the disposition curves. The disposition curves for the 2 commercial preparations were not different. Yohimbine, an antagonist of the pharmacologic effects produced by xylazine, did not alter the disposition of xylazine in the plasma. A single i.v. bolus of xylazine was completely described in 17 of 20 animals by the biexponential equation: Cp = 1.30e(-0.3955t) + 0.58e(-0.033t) where Cp represents the concentration of xylazine in the plasma at time t (min). The t1/...
Watson ED, Stokes CR, Bourne FJ.The influence of arachidonic acid metabolites on migration of equine neutrophils under agarose was investigated. Leukotriene B4 (LTB4) was chemotactic at concentrations between 0.1 and 1000 ng ml-1 and prostaglandin E2 (PGE2) at 1 and 10 ng ml-1 but not at higher or lower concentrations. Prostaglandin F2 alpha (PGF2 alpha) was not chemotactic for equine neutrophils at any concentration. Random migration was significantly inhibited (P less than 0.05) by suspension of neutrophils in LTB4 (0.1 to 1000 ng ml-1) and PGF2 alpha (0.1 ng ml-1) but not at high concentrations. There was a significant po...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Lungs from 19 Thoroughbred racehorses with a history of exercise-induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lun...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Gross post mortem examinations were performed on the lungs of 26 Thoroughbred horses of known exercise-induced pulmonary haemorrhage (EIPH) status. The most consistent finding was a variable degree of bilaterally symmetrical, dark discolouration of the dorsocaudal regions of the caudal lung lobes. In more severely affected lungs, the stained areas extended cranially along the dorsal surfaces of the lungs, and in some cases affected approximately one third of the lung surface. Discoloured areas of lung were denser than normal, collapsed less readily, often contained trapped air and were slow to...
Memon MA, McClure JJ, Usenik EA.An 8-year-old Quarter Horse stallion was admitted with a swelling involving the prepuce, dorsal part of the scrotum, and root of the penis. The swelling was first noticed 10 days after breeding, with no evidence that it had resulted from a kick by the mare. The penis was retracted into the prepuce, except for a 10- to 15-cm protrusion of the glans penis. Treatment included warm hydrotherapy, massage, stockinette compression, antidiuretics, antibiotics, penile support, and exercise, without success. At necropsy, a massive preputial hematoma was found extending forward from the root of the penis...
Varner DD, Ward CR, Storey BT, Kenney RM.Equine spermatozoa were incubated in a chemically defined medium for 8 hours. The medium preserved spermatozoal viability, as assessed by total spermatozoal motility, progressive spermatozoal motility, and spermatozoal exclusion of eosin stain. Effects of time and divalent cation ionophore, A23187, on the occurrence and character of the spermatozoal acrosome reaction were determined. Two light microscopic assays, a triple-stain technique and a chlortetracycline fluorescence assay, were calibrated with transmission electron microscopy for detection of the acrosome reaction. Incubation time and ...
Mair TS, Batten EH, Stokes CR, Bourne FJ.The distribution of mucosa-associated lymphoid tissue along the equine respiratory tract was surveyed in light microscopical sections. Intra-epithelial lymphocytes and similar cells scattered in the lamina propria were identified in all sites from the nasal vestibule to bronchioles of 2 to 4 mm diameter. Isolated lymphoid patches, occasionally with nodules, were common in bronchioles, but the density of this bronchiole-associated lymphoid tissue (BRALT) varied between individual horses. Bronchus-associated lymphoid tissue (BALT) was infrequently encountered. In the upper respiratory tract, nod...
McIlwraith CW, Yovich JV, Martin GS.The technique and results of arthroscopic surgery for the removal of osteochondral fragments from 1,000 carpal joints in 591 horses are reported. Of the 591 horses, 580 were racehorses (including 349 Quarter Horses and 220 Thoroughbreds). The distal aspect of the radial carpal bone was the most commonly affected site, followed by the proximal aspect of the intermediate carpal bone and distolateral aspect of the radius. More than one carpal joint was simultaneously operated on in 58.9% of the Quarter Horses and in 37.4% of the Thoroughbreds. Marked differences in the amount of damage were noted...
Clegg JB.The sequences of the linked alpha 2- and alpha 1-globin genes of the equine BI and BII haplotypes are greater than 99% identical within a 1.2-kb region extending from approximately 75 bp upstream of the putative cap site to a point approximately 150 bp 3' to the poly A addition signal. Differences between the alpha 2 and alpha 1 genes that are common to both haplotypes indicate that a major gene conversion occurred approximately 12 Myr ago and that this has been followed by shorter, more localized, conversions. Interhaplotype (allelic) comparisons at the alpha loci suggest that the BI and BII ...
Mair TS, Stokes CR, Bourne FJ.Lavage procedures were used to obtain samples of respiratory secretions from the nasal cavity, trachea, bronchi and bronchoalveolar level of apparently normal conscious horses, and the cellular composition of the lavage fluids was assessed. There was a progressive increase in total cell count of the secretions obtained from the upper to the lower respiratory tracts. Nasal lavage fluid was composed chiefly of epithelial cells, whereas tracheal, bronchial and bronchoalveolar fluids contained higher proportions of macrophages, lymphocytes and neutrophils. Eosinophils and mast cells were identifie...
Valieva TA, Valiev AG, Kulakova SN, Levachev MM.During six weeks rats were given a ration containing, as the only source of fat, lipids of sublimated mare's milk that had been stored with or without antioxidants (quercitrol, bisalcophen) during 3 months. The influence of specific quality of the ration fat on lipids and fatty acid composition of lipids in blood plasma, erythrocytic stroma and liver tissue, as well as on lipid peroxidation in the tissues was studied in the test animals. No changes induced by the lipids from sublimated mare's milk were detected in the parameters studied.
Watson ED, Stokes CR, Bourne FJ.Both random and directional migration of blood neutrophils from 9 mares susceptible to persistent endometritis were significantly less (p less than 0.05) than neutrophils from 8 resistant mares. Serum from susceptible mares had significantly more (p less than 0.01) chemotactic activity than serum from resistant mares. Although phagocytosis of yeast blastospores by blood neutrophils from 4 resistant and 3 susceptible mares was similar, uterine neutrophils from susceptible mares were significantly worse (p less than 0.01) at phagocytosis than uterine neutrophils from resistant mares. Uterine was...
Court MH, Engelking LR, Dodman NH, Anwer MS, Seeler DC, Clark M.The pharmacokinetics of dantrolene sodium were investigated in horses following both intravenous (2 mg/kg) and intragastric (4 mg/kg) administration. Two ponies also received dantrolene sodium intravenously (2 mg/kg) in a pilot study to obtain preliminary kinetic data and to determine urinary and biliary excretion of the intact drug. Distribution and elimination of dantrolene was rapid, resulting in an elimination half-life of 129 +/- 8 (SEM) min and a whole body clearance of 4.16 +/- 0.52 ml/min/kg. Following intragastric administration, dantrolene rapidly acheived peak concentrations within ...
Adams R, Nixon A, Hager D.Real-time ultrasound was used to identify a foreign-body abscess causing an extraluminal esophageal obstruction in the neck of a horse. Surgical exploration to remove the foreign body and drain the abscess was performed after 2 months of medical management that had failed to resolve the problem. The abscess could not be visualized because there was no draining tract or other localizing sign of inflammation. Ultrasound was used aseptically to guide surgical dissection to the walled off abscess with minimal damage to adjacent vital structures in the surgical field. The signs of esophageal obstru...
Jones RD, McGreevy PD, Robertson A, Clarke AF, Wathes CM.The design of 96 racehorse stables in the south west of England were surveyed. The 'typical' racehorse is kept in a loose box, bedded on straw and remains indoors while the stable is cleaned. It is given a floor area of 12 m2 and shares its airspace of 39 m3 with seven other horses. Overall, the predicted minimum rate of air change by natural convection in calm winds is 6.6 air changes/h but this is reduced to 2.2 if the top door of the stable is closed. On balance, racehorse stables in use today are based on designs which are worse overall than the best available in the 19th century.
Singh AK, Mishra U, Ashraf M, Abdennebi EH, Granley K, Dombrovskis D, Hewetson D, Stowe CM.Chemical ionization- and electron impact ionization-selective ion monitoring provided a simple and sensitive method for measuring detomidine (Domosedan), a potent sedative-analgesic drug for horses and cattle. Chemical ionization was at least 10 times more sensitive than electron impact ionization. By using propranolol as an internal standard, we found that the recovery of detomidine from the extraction procedure used in this study was greater than 75% for plasma, whole blood, or urine samples. Approximately 68% of detomidine was bound to plasma protein and 53% was bound to red blood cells.
Cooper HM, Jemmerson R, Hunt DF, Griffin PR, Yates JR, Shabanowitz J, Zhu NZ, Paterson Y.Comparative binding studies with peptide fragments of the whole antigen, or with evolutionarily related intact proteins with varying degrees of sequence homology, have been used extensively to map antigenic sites on proteins to the resolution of single amino acid residues. These methods are limited, however, since high affinity antibodies will often not react with peptides and evolutionarily related proteins are available for only a few antigens. In this study we use site-directed chemical modification of horse cytochrome c to identify residues involved in the binding sites of four monoclonal ...
Smith MR, Wright IM.A minimally invasive arthroscopic technique for removal of fractures of the lateral malleolus of the tibia is considered to be beneficial but data to this effect are required. Objective: Arthroscopic removal of fractures of the lateral malleolus of the tibia is technically feasible, provides a comprehensive evaluation of the tarsocrural joint and enables removal of remote comminuted fragments and disrupted short collateral ligaments. The technique is associated with low patient morbidity, requires only short periods of hospitalisation and affords a good prognosis to affected horses. Methods: T...
Hu D, Tang Y, Wang C, Qi Y, Ente M, Li X, Zhang D, Li K, Chu H.The microbiota and its metabolites play an important role in regulating the host metabolism and immunity. However, the underlying mechanism is still not well studied. Thus, we conducted the LC-MS/MS analysis and RNA-seq analysis on with and without horse botfly infestation to determine the metabolites produced by intestinal microbiota in feces and differentially expressed genes (DEGs) related to the immune response in blood and attempted to link them together. The results showed that parasite infection could change the composition of microbial metabolites. These identified metabolites could b...
Witherington DH.The post-race heart rates have been recorded in 1,000 Thoroughbreds following Flat, Hurdle and Steeplechase races in varying climatic conditions and on 54 different British racecourses. The post-race deceleration of the heart rate, under racecourse conditions, was marked by an apparent three-phase recovery period. Reference is made to the normal heart sounds and to the relationship between the heart and respiratory rates.
Zakopal J, Kubícek K, Koprivová M, Kepková K.A study was performed to examine microclimate in 14 stables belonging to 10 horsemen's teams and clubs; five of these houses were new-built. In five race-horse stables housing 16 horses each, on an average, where the optimum air temperature ranged from 10 degrees C to 12 degrees C, measurements and examinations were performed in the winter period and the following results were obtained: space per 1 horse housed 42.9 plus or minus 8.7 m-3, relative air humidity 74.3 plus or minus 3.8%, CO2 concentration 0.175 plus or minus 0.027%, NH3 concentration 0.00135 plus or minus 0.00044%. A large majori...
Stieger-Vanegas SM, Kippenes-Skogmo H, Nilsson E.An enostosis-like lesion was diagnosed in the left femur of a Swedish Warmblood horse that had a left hindlimb lameness of 3 weeks duration. With scintigraphy using technetium 99m-hydroxymethylene diphosphonate (99mTc-HDP) a marked regional focal increase in radioactivity was identified in the medullary cavity of the left femur. Radiographically there was a corresponding focal increase in bone opacity in the middiaphysis of the left femur. Histopathologically, a 5cm area of bone matrix was present in the diaphysis of the left femur and confirmed as an enostosis-like lesion. Enostosis-like lesi...
Lloyd KC, Kelly AB, Dunlop CI.A foal born 3 weeks prematurely was treated for respiratory distress, using a combination of oxygen therapy and mechanical ventilatory assistance. Clinical response and arterial blood gas tensions were monitored regularly. Continuous positive-airway pressure and intermittent positive-pressure ventilation administered via a nasotracheal tube were effective in improving arterial oxygenation and ventilatory function.
Martins EA, Silva LC, Baccarin RY.The objective of this study was to evaluate, through ultrasonography, the effect of medial patellar desmotomy. Middle patellar desmitis, enthesophytes in the patella, and irregularities in the cartilage of the femoral trochlear groove were observed. Medial patellar desmotomy leads to lesions in the stifle, and restriction of movement does not prevent these lesions from occurring. L’objectif de cette étude était d’évaluer, par échographie, l’effet d’une desmotomie du ligament médial de la rotule. Une desmite du ligament médial de la rotule, des enthésophytes dans la rotule et de...
Smith DF.The pathophysiology, diagnostic evaluation and medical management of the horse with intestinal obstruction is outlined. Emphasis is on early and accurate determination of the need for surgery and on providing optimal preoperative medical support.
Barton C, Hassel DM.A successful outcome to management of the critical colic patient is highly dependent on how the patient is monitored and treated, particularly, in the perioperative period. In this article, we will provide an update on monitoring techniques, advances in fluid therapy, nutrition management and pharmacotherapeutic agents, inclusive of pain monitoring and management, prokinetics, and management of systemic inflammatory response syndrome and the hypercoagulable state.
Smyth GB, Duran S, Ravis W, Clark CR.Histamine type II (H2) antagonists inhibit gastric acid secretion and are useful in treating gastric and duodenal ulcer disease. To provide some information on the pharmacokinetics of the H2 antagonist cimetidine, adult horses were given 3.3 mg/kg cimetidine intravenously (iv) or 3.3 and 10 mg/kg orally. Plasma cimetidine concentrations after 3.3 mg/kg orally were too low to measure. Following 3.3 mg/kg iv, cimetidine displayed two-compartment characteristics with a t1/2 of 0.083 +/- 0.039 h and t1/2 of 2.23 +/- 0.64 h. The total body clearance was 0.443 +/- 0.160 litre/h/kg and the mean resid...
Hussein KH, Elmeligy E, Khalphallah A, Al-Lethie AA.This study was performed to investigate the effects of cyclopentolate on ultrasonographic parameters of eye structures, intraocular pressure (IOP), tear production, and pupil size in normal donkeys. Sixteen eyes of eight clinically healthy adult donkeys (2-2.5 years old) weighing 295 ± 34 kg (mean ± standard deviation) were used in this study. Cyclopentolate hydrochloride 1% was instilled in a randomly selected eye and the other eye received normal saline drops as a control. The effect of cyclopentolate was evaluated by ultrasonography. Additionally, changes in IOP and tear production were ...
Dusek J, Munk Z.In a set of mares of English Thoroughbred horse of the Napajedla stock the gravidity length in the time period from 1880 to 1972 was evaluated. The variability of the gravidity length was evaluated in sets which were put together by combination of two age groups with a division of the studied time period into ten-year stages. Variance and sample means of the gravidity lengths in these sub-groups are significantly different in the period under study. In order to eliminate the action of non-genetic influences qualifying the variability of the gravidity length, and to increase the objectivity of ...
Altmeyer P, Holzmann H, Stöhr L, Koch HJ.White horses are subject to age-dependent coat depigmentation. They are dark gray or black at birth and lose their coloring between their second and fourth year. Beginning at about age 10 their coat takes on a characteristic silver-gray coloring. The purpose of this paper was to find out to what extent the endogenic alpha-MSH level changes with the change in pigmentation. alpha-MSH plasma levels were determined by radioimmunologic analysis in 3 age groups of white Camarque horses: age group 1 consisted of dark horses with a mean age of 1.2 years and a mean alpha-MSH level of 106.4 pg/ml +/- 18...
Bayly WM, Grant BD, Modransky PD.Arterial blood samples were collected during maximal exercise over 1.6 km in a thoroughbred horse with left laryngeal hemiplegia. Acid-base and blood gas measurements were performed on each sample and compared to the results from samples which were similarly collected 48 hours after laryngoplasty surgery was performed. Before surgery, the PaO2 was 53.2 mm Hg and the PaCO2 was 58.1 mm Hg after 1.6 km. After surgery, the corresponding results were 83.6 mm Hg (PaO2) and 39.0 mm Hg (PaCO2). There was no significant difference in the times taken for each gallop. The exercise intolerance associated ...
Neuhauser S, Gösele P, Handler J.During the peripartal period, interpretation of basic clinical signs may be challenging. In the present study, heart rate (HR), respiratory rate (RR) and body temperature (BT) were evaluated in healthy mares of different breed types and compared to reference values for adult horses from the literature. Methods: During daily physical exams of periparturient mares, the HR, RR and BT were evaluated. Differences according to the horse's size were investigated and in large breeds, the influence of dystocia or retained placenta was analysed. Results: During the last weeks before parturition (a. p.),...