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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.
Fractures of the lateral malleolus of the tibia in 16 horses. Clinical and radiological features of 16 horses with fractures of the lateral malleolus of the tibia are reported. The paper describes surgical techniques used, results obtained and discusses justification for removal. Fourteen fractures were unilateral and two bilateral. There was no left:right disparity. The history included a known traumatic incident in 14 cases. All animals had a tarsocrural joint effusion and 10 had palpable thickening of the lateral collateral ligaments. Crepitus was also palpable in 10 horses. The fracture was identified in all dorsoplantar and 14 of 18 dorsomedial-plan...
Anatomy of the prepubic tendon in the horse, cow, sheep, goat, and dog. Analyses of the fibers in the prepubic tendon of the horse and ruminants have shown that it is composed of the crossed and uncrossed tendons of origin of the pectineus muscles, the pelvic tendons of the rectus and obliquus abdominis muscles, and the tendons of origin of the cranial parts of the gracilis muscles. Pelvic attachments of the linea alba and the yellow abdominal tunic are incorporated in it. It is not a transverse ligament, and it is not homologous to the human superior (cranial) pubic ligament. The dog differs in 4 respects: (1) the pectineus tendons do not cross, but each originat...
Diagnostic methods for African horsesickness virus using monoclonal antibodies to structural and non-structural proteins. A panel of 32 hybridoma cell lines secreting monoclonal antibodies (MAbs) reactive with African horsesickness virus serotype 4 (AHSV-4) has been developed. Four of the MAbs recognized the major core antigen VP7, twenty recognized the outer capsid protein VP2 and eight reacted with the non-structural protein NS1. With the VP7-specific MAbs a rapid and sensitive double antibody sandwich immunoassay has been developed to detect viral antigen in infected Vero cells and in spleen tissue from AHSV-infected horses. The sensitivity of the assay is 10 ng viral antigen per 100 microliters. The NS1-speci...
African horse sickness in Spain. The aetiology, pathogenesis and epizootiology of African horse sickness (AHS) are reviewed with special reference to recent outbreaks in the Iberian peninsula. AHS is a highly fatal insect-borne viral disease of Equidae. It is caused by an Orbivirus (family Reoviridae) and nine serotypes are recognised. Outbreaks occurred in central Spain in 1987 and in southern regions of the Iberian peninsula in 1988, 1989 and 1990. All were associated with serotype 4 of the virus, whereas other occurrences of AHS outside Africa have all been caused by serotype 9. The clinical picture in the outbreaks was ma...
A kinematic and strain gauge study of the reciprocal apparatus in the equine hind limb. Hind limb kinematics were recorded in five horses at walk and trot using an opto-electronic CODA-3 system. Simultaneously, in vivo strain in the completely tendinous peroneus tertius muscle was registered by implanted mercury-in-silastic strain gauges. The origin-insertion length patterns of the peroneus tertius were calculated from raw kinematic data and from data corrected for the error caused by skin displacement, and compared with the directly measured strain. The strain patterns calculated from externally measured kinematic data appeared to be in accordance with the directly measured stra...
Pedunculated lipomas as a cause of intestinal obstruction in horses: 17 cases (1983-1990). The medical records of 17 horses that were evaluated and treated because of colic caused by pedunculated lipomas between 1983 and 1990 were reviewed. The mean age of the horses was 16.6 +/- 3.9 years (range, 10 to 26 years), which was significantly greater than that of the population of horses evaluated because of colic (control population) during the same period. There were significantly more geldings (76.5%), compared with the control population. Nasogastric reflux ranged from 1 to 16 L in 8 horses and was not obtained in 9 horses. Abdominal palpation per rectum revealed small intestinal dis...
Cross-reactivity of existing equine influenza vaccines with a new strain of equine influenza virus from China. A novel strain of equine influenza virus, influenza A/equine/Jilin (China)/1/89, has emerged which is genetically distinct from all earlier strains of equine influenza. It is therefore possible that the vaccines against equine influenza may be unable to protect horses against disease caused by this virus strain. In vitro serological assays established that there were low levels of immunological cross-reactivity between the new virus, the current vaccine strains and the strains of equine-2 influenza virus now in circulation.
Ventricular arrhythmias in horses: 21 cases (1984-1989). Ventricular premature depolarizations (VPD) were identified in 21 horses in which unexplained tachycardia or an arrhythmia was detected on auscultation. Horses were categorized into 3 groups on the basis of ECG findings. Seven horses had uniform isolated VPD (group 1); 7 horses had repetitive uniform VPD at a rate or = 100 VPD/min (group 3). Concurrent systemic disease was identified in 12 horses, 7 of which had gastrointestinal tract disorders. Serum cardiac isoenzyme activities were high in 6 (2 from each group) of 13 horses in which they were measured. Serum electrolyte concentrations were...
Comparison of lidocaine, xylazine, and xylazine/lidocaine for caudal epidural analgesia in horses. Caudal epidural analgesia was achieved in 6 adult horses on 3 successive occasions at weekly intervals by injection of lidocaine, xylazine, and a combination of lidocaine/xylazine through indwelling epidural catheters. Analgesia was defined as a lack of response to pinprick and hemostat pressure in the skin of the perineal area. A significant (P < 0.05) difference was not found for time of onset of analgesia between lidocaine (4.3 +/- 0.8 minutes, mean +/- SEM) and the lidocaine/xylazine combination (5.3 +/- 1.3 minutes). Time to onset of analgesia after administration of xylazine was signi...
Bilateral ureterocystostomy in a 450-kg horse with ectopic ureters. A 450-kg yearling Clydesdale filly was determined to have bilateral ectopic ureters. The resulting incontinence caused severe malodorous perineal dermatitis. Bladder capacity was measured at 800 ml. The urethral sphincter lacked tone, and the horse was seen to urinate in a normal manner only 2 or 3 times a week. A midline celiotomy was performed, and the ureters were identified by cannulation from the ectopic openings. The ureters were ligated, and the cut ends were anastomosed to the dorsal bladder surface by an extravesicular end-to-side technique. A partial thickness seromuscular layer of t...
Ionized calcium concentration in horses with surgically managed gastrointestinal disease: 147 cases (1988-1990). Packed cell volume, total plasma protein, serum sodium, potassium, and ionized Ca2+ concentrations, and blood pH were determined at the time of admission and following surgery in 147 horses with acute abdominal crisis. Horses were allotted to 3 categories on the basis of the surgical lesion: (1) nonstrangulating obstruction of the ascending or descending colon (category A, n = 76), (2) strangulating and nonstrangulating infarction of the cecum or ascending colon (category B, n = 37), and (3) strangulating and nonstrangulating infarction of the small intestine (category C, n = 25). Horses with ...
Arthroscopic removal of a palmar radial osteochondroma causing carpal canal syndrome in a horse. A 5-year-old Arabian stallion with moderate effusion in the right carpal canal and intermittent lameness in this limb was diagnosed to have an osteochondroma projecting from the distal portion of the radius into the carpal canal. oral phenylbutazone treatment over the next 3 years allowed the stallion to continue its show career. Right forelimb lameness returned at that time, and ultrasonography revealed the osteochondroma impinging on the dorsal surface of the deep digital flexor tendon. The owner elected to have the osteochondroma surgically removed. The horse was anesthetized, and the carpa...
Primary meningeal lymphoma in a horse. Primary meningeal lymphoma was diagnosed in an 18-year-old Morgan gelding. The horse was examined because of a 3-day history of progressive ataxia and weakness. The gait abnormalities were worse on the left side, and the pelvic limbs were more affected than the thoracic limbs. Additional findings included signs of depression, miosis of the left pupil, ptosis of the left upper eyelid, and areas of muscle atrophy on the left side of the neck and over the dorsal aspect of the left scapula. Inflammatory changes were evident in the CSF. At necropsy, there was diffuse and irregular thickening of the...
Microvascular permeability changes in ischemia/reperfusion injury in the ascending colon of horses. The normal microvascular permeability of the ascending colon in horses and the microvascular permeability of that segment after ischemia and reperfusion were investigated. Microvascular permeability was estimated by the ratio of lymphatic protein to plasma protein concentration (Cl/Cp) at high lymph flow rates in 8 adult horses in 2 equal groups: normal and ischemic (2-hour period). Lymphatic flow rates and lymph and plasma protein concentrations were determined. Intestinal biopsy specimens were obtained at the end of each experiment. Flow independent values were selected and compared by one-w...
Postanesthetic recumbency associated with hyperkalemic periodic paralysis in a quarter horse. Anesthesia and surgery in a Quarter Horse affected with hyperkalemic periodic paralysis resulted in euthanasia after 7 days of postoperative recumbency. Initial recovery was uneventful after extensive sinus surgery, but within 2 hours, the horse had severe muscle weakness. Plasma electrolyte concentrations were within the normal range during the period of recumbency. There was no clinical or laboratory evidence of severe muscle damage. Despite treatment with acetazolamide, isoproterenol, and intensive nursing, the horse was unable to stand for more than a few seconds and developed severe decub...
Distribution of coronary collateral blood flow at different levels of collateral growth in conscious ponies. Coronary collateral growth was stimulated in chronically instrumented conscious ponies by a previously validated intermittent coronary occlusion method. Changes in regional myocardial function (sonomicrometry) and reactive hyperemia (Doppler method) were used to monitor collateral growth and to program measurements of regional myocardial blood flow (microsphere method). A serial analysis of the transmural and lateral distributions of collateral blood flow was performed at the native and three superimposed levels of collateral growth. Results in nine animals undergoing an average of 553 +/- 188...
Equine protozoal myelitis in Panamanian horses and isolation of Sarcocystis neurona. Schizonts of Sarcocystis neurona were identified microscopically in hematoxylin-eosin-stained spinal cord sections from 2 native Panamanian horses that exhibited clinical signs of equine protozoal myelitis (EPM). Spinal cord homogenate from a third Panamanian horse with EPM was inoculated onto monolayers of cultured bovine monocytes (M617). Intracytoplasmic schizonts containing merozoites arranged in rosette forms surrounding a central residual body first were observed 13 wk postinoculation. Parasites divided by endopolygeny and lacked rhoptries. Schizonts from each horse reacted with Sarcocys...
Pharmacokinetics of metronidazole and its concentration in body fluids and endometrial tissues of mares. Serum concentrations of metronidazole were determined in 6 healthy adult mares after a single IV injection of metronidazole (15 mg/kg of body weight). The mean elimination rate (K) was 0.23 h-1, and the mean elimination half-life (t1/2) was 3.1 hours. The apparent volume of distribution at steady state was 0.69 L/kg, and the clearance was 168 ml/h/kg. Each mare was then given a loading dose (15 mg/kg) of metronidazole at time 0, followed by 4 maintenance doses (7.5 mg/kg, q 6 h) by nasogastric tube. Metronidazole concentrations were measured in serial samples of serum, synovia, peritoneal flui...
Ultrastructure of Brunner’s glands in the horse. Investigation of the duodenal submucosal glands of Brunner in the horse for the first time at the ultrastructural level has clarified some of the unique features of these equine glands. The horse is one of the very few mammals in which Brunner's glands are comprised of both mucous and serous tubuloacinar glands. Although the ultrastructural differences between the serous and mucous cell types are marked, particularly with respect to secretory granules and rough endoplasmic reticula, these cell types closely correspond to serous and mucous cells in the upper digestive system of other mammals. A...
Bronchoscopy of the horse. The endobronchial anatomy of 12 lung specimens from horses and 12 healthy, standing, sedated horses was evaluated, using a 200-cm-long, 9.5-mm-diameter videoendoscope. On the basis of these findings, the nomenclature system of Amis and McKiernan was modified for identification of airways of horses during bronchoscopy. Lobar bronchi are identified on the basis of the side of the bronchial tree on which they were found and the order in which they originated from the primary bronchus. Thus, RB1, RB2, and RB3 referred to right cranial lobar bronchus, respectively. On the left side, the designation...
Evaluation of clinical signs of disease, bronchoalveolar and tracheal wash analysis, and arterial blood gas tensions in 13 horses with chronic obstructive pulmonary disease treated with prednisone, methyl sulfonmethane, and clenbuterol hydrochloride. We evaluated the efficacy of 3 treatments for chronic obstructive pulmonary disease in horses: prednisone (400 mg/horse, PO, daily; n = 7), methyl sulfonmethane (10 g/horse, PO, q 12 h; n = 6), and clenbuterol hydrochloride (0.4 mg/horse, PO, q 12 h; n = 7). A fourth group acted as controls (n = 6) and was not treated. The treatment period lasted 10 days. Each horse was a member of 2 different groups for 10 days, separated by an 18-day interval of no treatment. All horses were housed together in an outdoor pen without bedding. Horses were fed alfalfa/grass hay mix ad libitum from a large feede...
Effects of xylazine on airway function in ponies with recurrent airway obstruction. The effect of IV administration of the alpha 2-adrenoceptor agonist xylazine hydrochloride (0.5 mg/kg of body weight) was examined in ponies with recurrent obstructive pulmonary disease, commonly called heaves. Six ponies with the disease (principals) were studied during clinical remission and during an acute attack of airway obstruction precipitated by stabling and feeding of dusty hay. Six control ponies were also studied. In principal ponies with airway obstruction, xylazine administration significantly (P < 0.05) decreased pulmonary resistance and increased dynamic compliance, but did n...
Furosemide-induced electrolyte depletion associated with echinocytosis in horses. Echinocytes have been incriminated in the pathogenesis of exertional diseases in horses. To evaluate the hypothesis that echinocytes are dehydrated erythrocytes, we decreased blood sodium and potassium concentrations in 4 horses by administering furosemide (1.0 mg/kg of body weight, q 12 h) for 2 days and we monitored CBC, serum and erythrocyte sodium and potassium concentrations, and echinocyte numbers. Serum sodium concentration decreased progressively over the 48 hours of furosemide administration, then returned to near baseline concentration at 168 hours. A statistically significant decrea...
Low energy laser irradiation treatment for second intention wound healing in horses. Low energy helium-neon laser irradiation was administered to full thickness skin wounds (3 cm x 3 cm) on the dorsal surface of the metacarpophalangeal/metatarsophalangeal joints and cranial surface of the tarsocrural joints of eight horses. The effects on wound healing were analyzed statistically. There were no differences (p > 0.55) observed in the rate of wound healing between the low energy laser irradiated wounds and the control wounds. There was a significant difference (p < 0.006) observed in the rate of healing between the anatomical sites. Tarsal wounds healed more rapidly than fetlock...
Ultrastructure of cilia in horses. This paper presents some ultrastructural details of cilia from the ciliated tracheal epithelium of healthy horses. By using a new fixation method, the Authors were able to describe minute details, some of which have been only rarely observed in other species and mostly by means of the freeze-etch technique (i.e. electron dense particles of ciliary necklace). The Authors justify the need to investigate the ultrastructural details of cilia in various species since the minute morphological differences might be functionally significant.
Serological responses of specific pathogen-free foals to equine herpesvirus-1: primary and secondary infection, and reactivation. Serum antibody (virus neutralisation, complement fixation, IgM and IgG) responses to equine herpesvirus-1 (EHV-1) infection were measured in six foals which were initially free from EHV-1 and EHV-4 infection and maternally-derived antibodies. Following primary infection, high titres of virus neutralisation and complement fixation antibodies were detectable against EHV-1, however, corresponding antibody levels against EHV-4 were low or inapparent, although the two viruses share a number of cross-reactive epitopes. In addition, following the primary infection with EHV-1, IgM levels increased bef...
