Miniature Horses primarily differ from horses in size, conformation, and certain physiological traits. Miniature Horses are bred to retain the characteristics of full-sized horses on a smaller scale, typically measuring less than 34–38 inches in height at the withers, depending on the registry. In contrast, horses encompass a wide range of breeds and sizes, generally standing over 14.2 hands (58 inches) tall. While both Miniature Horses and horses share similar anatomical and physiological features, their size differences can influence aspects such as metabolism, health care needs, and management practices. This page compiles peer-reviewed research studies and scholarly articles that explore the genetics, health considerations, and management practices associated with Miniature Horses and horses, highlighting both their similarities and distinctions.
Camacho-Rozo CA, Santos GO, Wenzen DP, Cousseau SB, Wronski JG, Argenta FF, Winter GHZ, Pavarini SP, Mattos RC.This report describes a case of sudden death of a pregnant miniature mare due to an acute ovarian hemorrhage leading to fatal hemoperitoneum. The miniature horse was a 12-year-old female, 60 days pregnant, with a body condition score of 7 (1-9), with a history of obesity and laminitis. Necropsy revealed hemoperitoneum due to an ovarian capsule rupture and hemorrhage after a physiological supplementary ovulation and luteinization. Ovarian rupture after ovulation is uncommon in mares.
Al Abri MA, Holl HM, Kalla SE, Sutter NB, Brooks SA.The domesticated horse has played a unique role in human history, serving not just as a source of animal protein, but also as a catalyst for long-distance migration and military conquest. As a result, the horse developed unique physiological adaptations to meet the demands of both their climatic environment and their relationship with man. Completed in 2009, the first domesticated horse reference genome assembly (EquCab 2.0) produced most of the publicly available genetic variations annotations in this species. Yet, there are around 400 geographically and physiologically diverse breeds of hors...
Graves KT, Eberth JE, Bailey E.Homozygous and compound heterozygous Miniature horses for ACAN alleles D1, D2, D3* and D4 exhibit chondrodysplastic dwarfism (OMIA 001271-9796). In a previous study, the carrier rate for these four alleles, combined, was 26.2%. The purpose of this study was to investigate whether carriers of these dwarfism-causing alleles had a shorter withers height than non-carriers. A total of 245 Miniature horses were tested for these four ACAN alleles and also were measured for withers height. Of these horses, 98 were carriers and 147 were non-carriers. A statistically significant difference of 1.43 inche...
Andrade DGA, Basso RM, Castiglioni MCR, Silva JP, Machado VMV, Laufer-Amorim R, Borges AS, Oliveira-Filho JP.Four causative mutations (D1, D2, D3*, and D4) of chondrodysplastic dwarfism have been described in the equine () gene. Homozygotes for one of these mutations and heterozygotes for any combination of these mutations exhibit the disproportionate dwarfism phenotype. However, no case description of homozygotes for D4 (D4/D4) has been reported in the literature, to our knowledge. We report 2 Miniature horses with the genotype D4/D4 in the gene. Clinically, the 2 dwarfs had a domed head that was large compared to the rest of the body, mandibular prognathism, and short and bowed limbs, mainly in t...
Every LJ, Hostnik ET, Hostnik LD, Yardley J, Shore-Khirallah AT, Thompson A, Linn SC.Tracheal collapse in horses is reportedly uncommon; however, American Miniature Horses are more commonly affected. There is no description of the tracheal luminal diameter of American Miniature Horses, making early detection of tracheal luminal narrowing difficult. Objective: To 1) describe radiographic tracheal luminal diameter in clinically normal American Miniature Horses, 2) report the prevalence of subclinical tracheal collapse in a population of American Miniature Horses, and 3) use tracheal videofluoroscopy to quantify variation in tracheal luminal diameter throughout the respiratory c...
Tanaka J, Leeb T, Rushton J, Famula TR, Mack M, Jagannathan V, Flury C, Bachmann I, Eberth J, McDonnell SM, Penedo MCT, Bellone RR.Mushroom is a unique coat color phenotype in Shetland Ponies characterized by the dilution of the chestnut coat color to a sepia tone and is hypothesized to be a recessive trait. A genome wide association study (GWAS), utilizing the Affymetrix 670K array (MNEc670k) and a single locus mixed linear model analysis (EMMAX), identified a locus on ECA7 for further investigation ( = 2.08 × 10). This locus contained a 3 Mb run of homozygosity in the 12 mushroom ponies tested. Analysis of high throughput Illumina sequencing data from one mushroom Shetland pony compared to 87 genomes from horses of var...
Heck L, Sanchez-Villagra MR, Stange M.Much of the shape variation found in animals is based on allometry and heterochrony. Horses represent an excellent model to investigate patterns of size-shape variation among breeds that were intentionally bred for extreme small and large sizes. Methods: We tested whether ponies (wither height < 148 cm) have a diverging size-shape relationship in skull shape as compared to regular-sized horse breeds (wither height > 148 cm, here-after called horses) during ontogenetic growth. We used a dataset of 194 specimens from 25 horse and 13 pony breeds, two of which are miniature breeds (wither height <...
Trumpp KM, Parsley AL, Lewis MJ, Camp JW, Taylor SD.Tick paralysis has not been reported in horses in North America. Results: Two American Miniature horses were examined for progressive weakness and recumbency. Numerous ticks (Dermacentor variabilis) were found on both horses. Horse 1 was recumbent (grade 5/5 gait deficit) on presentation, whereas Horse 2 was standing but ataxic (grade 4/5 gait deficit) and tetraparetic. Both horses had decreased tongue and tail muscle tone, and had normal spinal reflexes. Cerebrospinal fluid cytology was normal. Equine herpesvirus-1 testing was negative. Unassigned: Ticks were removed within 24 hours of pres...
Catalano DN, Coleman RJ, Hathaway MR, Neu AE, Wagner EL, Tyler PJ, McCue ME, Martinson KL.Adding breed type, height, and neck circumference to body length and girth circumference improves bodyweight (BW) estimation in different breeds of horses; however, equations have not been developed for all breed types. The objectives were to develop BW estimation equations for Miniature, saddle-type, and Thoroughbred horses using morphometric measurements. Measurements were collected on adult (≥3 years, nonpregnant) saddle-type (n = 209), adult (n = 249) and juvenile (<3 years, n = 61) Miniatures, and adult Thoroughbreds (n = 100). Personnel determined body condition score (BCS), m...
Endo H, Nguyen ST, Yoshida M, Kudo K.The three-dimensionally real position and movement of the scapula in the lateral side of the ribcage could not be clarified in the horse, since the body size of the horse is too large to apply the CT scanning and image analysis methods. In this study, therefore, we examined the position and the movability of scapula using a carcass of the Falabella which is one of the smallest breeds of the horse. The whole skeletal system in thoracic part of the Falabella could be three-dimensionally observed by CT scanning method. The three-dimensional images show that the scapula cranially slides and the ve...
Stein L, Sledge D, Smedley R, Kiupel M, Thaiwong T.A 15-y-old Miniature horse mare had a 6-mo history of an ulcerated mass on the right lower eyelid. An incisional biopsy and a subsequent excisional biopsy were submitted to the Michigan State University Veterinary Diagnostic Laboratory for microscopic evaluation. Histologically, the incisional biopsy was composed of sheets of large neoplastic vacuolated polygonal cells. A few regions contained poorly differentiated neoplastic round-to-basaloid cells that rimmed the sheets of highly vacuolated polygonal cells. Both vacuolated and basaloid cells exhibited strong perimembranous and cytoplasmic im...
Crosa AT, Desjardins MR.OBJECTIVE To describe use of a modified open castration technique with a scrotal approach and primary closure in equids. DESIGN Prospective case series. ANIMALS 38 client-owned, sexually intact male equids. PROCEDURES With owner consent, elective castration was performed with a modified open technique on patients (1 pony, 1 miniature horse, and 36 horses of other breeds) under general anesthesia. The procedure included minimal dissection into the scrotal region for removal of testes, with cremaster muscles left intact and the parietal vaginal tunic closed in place. Primary closure of surgical ...
Hazlett M, Stalker M, Lake M, Peregrine A.A miniature horse which died following humane seizure from an Ontario farm was emaciated with serous atrophy of fat. Autopsy revealed hepatic atrophy and moderate periportal fibrosis. Eggs and trematodes seen in the liver were identified as Dicrocoelium dendriticum. This appears to be the first reported case of infection of equids in North America with Dicrocoelium dendriticum. Infection parDicrocoelium dendriticumhépatique chez un cheval miniature. Un cheval miniature qui est mort à la suite d’une saisie humanitaire dans une ferme de l’Ontario était émacié et avait une atrophie sére...
Eberth JE, Graves KT, MacLeod JN, Bailey E.Chondrodysplastic dwarfism in Miniature horses appeared to be a recessive genetic trait based on the occurrence of affected offspring by normal parents. Dwarf phenotypes vary and range from abnormal abortuses to viable offspring with evidence of skeletal dysplasia. A genome-wide association study implicated a region of ECA1 with dwarfism in Miniature horses. Aggrecan (ACAN) was a candidate gene in that region, and exons were sequenced to compare DNA sequences for dwarf and non-dwarf horses. Sequencing led to the discovery of variants in exons 2, 6, 7 and 15 associated with dwarfism. The four v...
Metzger J, Rau J, Naccache F, Bas Conn L, Lindgren G, Distl O.Miniature size in horses represents an extreme reduction of withers height that originated after domestication. In some breeds, it is a highly desired trait representing a breed- or subtype-specific feature. The genomic changes that emerged due to strong-targeted selection towards this distinct type remain unclear. Results: Comparisons of whole-genome sequencing data from two Miniature Shetland ponies and one standard-sized Shetland pony, performed to elucidate genetic determinants for miniature size, revealed four synergistic variants, limiting withers height to 34.25 in. (87 cm). Runs of h...
Clarke DL.Chondromalacia of the tracheal and bronchial cartilages and redundancy of the dorsal tracheal membrane result in collapse of the large airways, leading to coughing and airway obstruction. It most commonly affects small-breed dogs, although larger-breed dogs, cats, and miniature horses are also sporadically reported. Dynamic airway imaging is used to confirm the diagnosis. The primary goal of medical management is to control clinical signs attributable to coughing and airway inflammation. When this is no longer effective, tracheal stents provide a minimally invasive, rapid way to restore airway...
Pozor M, Conley AJ, Roser JF, Nolin M, Zambrano GL, Runyon SP, Kelleman AA, Macpherson ML.Recently, anti-Müllerian hormone (AMH) was validated as a reliable marker of testicular damage caused by various chemotherapy drugs in humans and in mice. In horses, the reference values of AMH concentrations in normal stallions, during different seasons of a year, have been recently reported. However, this hormone was not evaluated in subfertile or infertile stallions with testicular damage. Therefore, the objective of this study was to investigate the effects of experimentally induced testicular degeneration on the concentration of AMH in stallions. Severe but transient testicular degenerat...
Goodrich EL, Mittel LD, Glaser A, Ness SL, Radcliffe RM, Divers TJ.This case report describes an outbreak and novel findings associated with a beta coronavirus (BCoV) infection that occurred on an American Miniature Horse (AMH) breeding farm in upstate New York, in January and February of 2013. Twenty-nine AMH and one donkey were present on the farm when the outbreak occurred. One 10-year-old Quarter Horse mare, stabled at a separate location and owned by an employee of the farm, also tested positive. A polymerase chain reaction (PCR) assay for the detection of BCoV was performed at the Animal Health Diagnostic Center (AHDC) at Cornell on all faecal samples. ...
Knickelbein KE, Stock M, Carrasco SE, Reilly CM, Lassaline ME.An 18-year-old American Miniature Horse mare was presented with a complaint of a scleral swelling affecting the right eye and a history of suspected trauma 6 weeks prior to evaluation. Clinical findings included severe blepharospasm, a bulbous swelling of the dorsotemporal bulbar conjunctiva, and phthisis bulbi. Ocular ultrasound was recommended but declined. Enucleation was elected for the blind, painful eye and was performed standing. Gross and histopathologic examinations of the globe were consistent with extrusion of the lens to the episcleral space, which is classified as a traumatic pha...
Nijdam P, Elmas C, Fugazzola MC.A 1-month-old Miniature Shetland colt was presented to the Burg Müggenhausen Equine Clinic. Primary complaints were regurgitation of milk, bilateral white nasal discharge, and weakness. Physical examination, endoscopy of the esophagus, and contrast radiography led to the diagnosis of an esophageal stricture and aspiration pneumonia. Surgical treatment by means of an esophagomyotomy was performed. The foal improved only temporarily and multiple sessions of endoscopic balloon dilation of the esophagus were performed afterwards. 12 months after the final treatment the foal was healthy and had no...
Siwinska N, Zak A, Baron M, Cylna M, Borowicz H.The aim of this study was to determine the normal location, wall thickness and motility of the right dorsal colon in adult ponies and miniature horses. The abdominal ultrasonography examination was performed in a study group consisting of 23 ponies and miniature horses and in a control group comprising ten Thoroughbred horses. The procedure was performed in unsedated standing animals. The location and the thickness of the right dorsal colonic wall was examined on the right side of the abdomen between the 10th and the 14th intercostal space. The contractility was recorded in the 12th intercosta...
Dunkel B, Buonpane A, Chang YM.Clinical impression suggests that some gastrointestinal lesions are more common in certain horse types. The study tested the hypothesis that relative prevalence of acute gastrointestinal lesions differs between equid types. In a retrospective caseâ€"control study, records (2010â€"2015) were reviewed for equids with acute gastrointestinal disease. Signalment, details of gastrointestinal lesions and diagnoses were recorded. Animals were categorised as miniature type, pony, Arabian, light breed or draft type. Exclusion criteria were no recorded breed/size/diagnosis, age less than one year a...
Boegheim IJM, Leegwater PAJ, van Lith HA, Back W.Impairment of bone growth at a young age leads to dwarfism in adulthood. Dwarfism can be categorised as either proportionate, an overall size reduction without changes in body proportions, or disproportionate, a size reduction in one or more limbs, with changes in body proportions. Many forms of dwarfism are inherited and result from structural disruptions or disrupted signalling pathways. Hormonal disruptions are evident in Brooksville miniature Brahman cattle and Z-linked dwarfism in chickens, caused by mutations in GH1 and GHR. Furthermore, mutations in IHH are the underlying cause of creep...
Ludwig EK, Byron CR.A 2-year-old, 8-weeks pregnant, non-weight bearing miniature horse mare was treated for a 6-day-old left coxofemoral joint luxation with a femoral head ostectomy. The procedure had no negative effects on pregnancy or parturition and 23 months following surgery the horse had minimal lameness. Une jument miniature non portante gravide de 8 semaines et âgée de 2 ans a été traitée pour une luxation de l’articulation coxofémorale gauche datant de 6 jours à l’aide d’une ostectomie de la tête fémorale. L’intervention n’a pas eu d’effets négatifs sur la gestation ou la parturiti...
Metzger J, Gast AC, Schrimpf R, Rau J, Eikelberg D, Beineke A, Hellige M, Distl O.The Miniature Shetland pony represents a horse breed with an extremely small body size. Clinical examination of a dwarf Miniature Shetland pony revealed a lowered size at the withers, malformed skull and brachygnathia superior. Computed tomography (CT) showed a shortened maxilla and a cleft of the hard and soft palate which protruded into the nasal passage leading to breathing difficulties. Pathological examination confirmed these findings but did not reveal histopathological signs of premature ossification in limbs or cranial sutures. Whole-genome sequencing of this dwarf Miniature Shetland p...
Butler J, Khan S, Scarzella G.Two young American miniature horses from the same farm were evaluated by a veterinarian due to presence of lethargy, anorexia, and cardiac arrhythmias. Both horses were treated aggressively with IV fluids and other supportive measures. The first horse died approximately 72 hr after the start of clinical signs and the second horse was humanely euthanized due to poor response to treatment. Oleander toxicosis was suspected based on the types of clinical signs present and due to several oleander plants and dried leaves present on the property. Oleander toxicosis was confirmed by the presence of ol...
Hardeman LC, van der Meij BR, Back W, van der Kolk JH, Wijnberg ID.In equine laminitis, the deep digital flexor muscle (DDFM) appears to have increased muscle force, but evidence-based confirmation is lacking. Objective: The purpose of this study was to test if the DDFM of laminitic equines has an increased muscle force detectable by needle electromyography interference pattern analysis (IPA). Methods: The control group included six Royal Dutch Sport horses, three Shetland ponies and one Welsh pony [10 healthy, sound adults weighing 411 ± 217 kg (mean ± SD) and aged 10 ± 5 years]. The laminitic group included three Royal Dutch Sport horses, one Friesian, o...
Frischknecht M, Jagannathan V, Plattet P, Neuditschko M, Signer-Hasler H, Bachmann I, Pacholewska A, Drögemüller C, Dietschi E, Flury C, Rieder S....The identification of quantitative trait loci (QTL) such as height and their underlying causative variants is still challenging and often requires large sample sizes. In humans hundreds of loci with small effects control the heritable portion of height variability. In domestic animals, typically only a few loci with comparatively large effects explain a major fraction of the heritability. We investigated height at withers in Shetland ponies and mapped a QTL to ECA 6 by genome-wide association (GWAS) using a small cohort of only 48 animals and the Illumina equine SNP70 BeadChip. Fine-mapping re...
Rodríguez-Sánchez IP, Treviño-Alvarado VM, Torres-Sepúlveda Mdel R, López-Saldaña LA, Ponce-García G, López-Uriarte GA, Ruiz-Herrera Mdel C....Free amino acids and acylcarnitines circulating in the blood can be used for diagnosis for metabolic illness and imbalances. To date, the normal reference ranges of amino acids and acylcarnitines in horse peripheral blood have not been established. In this study, the concentrations of 12 amino acids and 26 acylcarnitines were determined by tandem mass spectrometry in complete blood from 100 healthy horses (50 Quarter horses (QH) [23 males and 27 females] and 50 American Miniature horses (AMH) [15 males and 35 females]) with no signs of metabolic disease. The means and standard deviations were ...
Wobeser BK.During a widespread anthrax outbreak in Canada, miniature horses were vaccinated using a live spore anthrax vaccine. Several of these horses died from an apparent immune-mediated vasculitis temporally associated with this vaccination. During the course of the outbreak, other miniature horses from different regions with a similar vaccination history, clinical signs, and necropsy findings were found. Vaccin contre l’anthrax associé à la mort de chevaux miniatures. Durant une vaste éclosion d’anthrax au Canada, des chevaux miniatures ont été vaccinés en utilisant un vaccin à base de sp...
Reed KJ, Kunz IGZ, Scare JA, Nielsen MK, Turk PJ, Coleman RJ, Coleman SJ.As hindgut fermenters, horses are especially dependent on the microbiota residing in their cecum and large intestines. Interactions between these microbial populations and the horse are critical for maintaining gut homeostasis, which supports proper digestion. The current project was motivated to determine if any features of the fecal microbiota are informative of the microbial communities from the cecum, ventral colon, or dorsal colon. Digesta from the cecum, ventral colon, dorsal colon and feces were collected from 6 yearling miniature horses. Microbial DNA was isolated and the microbiota fr...
Plummer CE, Ramsey DT.To determine the incidence of ocular abnormalities in miniature horses. Methods: Descriptive study. Methods: Fifty-three miniature horses. Methods: Ophthalmic examinations were performed using diffuse and focal illumination, slit-lamp biomicroscopy and indirect ophthalmoscopy. Coat color, mane and tail color, age and gender were recorded with results of ophthalmic examination. Results: Ocular abnormalities detected most frequently consisted of cysts arising from the posterior iris, ciliary body, and peripheral retina, curvilinear streaks of retinal pigmented epithelium extending from the perip...
Mogg TD, Palmer JE.The medical records of 23 American Miniature Horses with hyperlipidemia, hyperlipemia, or hepatic lipidosis were reviewed. The most common clinical signs were anorexia and lethargy. The mean duration of clinical signs was 2.4 days. A primary disease was identified in 19 cases. Enterocolitis was the most common primary disease (n = 10). Intentional feed restriction, as part of treatment for colic, resulted in hyperlipemia in 2 horses and hyperlipidemia in 1. Four horses had primary hyperlipemia, 3 of which had signs of hepatoencephalopathy secondary to hepatic lipidosis. Dextrose, heparin, and ...
Dunkel B, Kapff JE, Naylor RJ, Boston R.Clinical impression suggested that pony and miniature breeds (collectively referred to as ponies) presenting to a referral hospital for investigation of gastrointestinal disease had higher blood lactate concentrations on admission than large breed horses. Objective: The study tested the hypothesis that ponies with gastrointestinal disease had higher blood lactate concentrations on admission than large breed horses with similar disease severity. Methods: Retrospective case-control study. Methods: Medical records from September 2006 to July 2011 were reviewed for ponies with a primary presenting...
Trumpp KM, Parsley AL, Lewis MJ, Camp JW, Taylor SD.Tick paralysis has not been reported in horses in North America. Results: Two American Miniature horses were examined for progressive weakness and recumbency. Numerous ticks (Dermacentor variabilis) were found on both horses. Horse 1 was recumbent (grade 5/5 gait deficit) on presentation, whereas Horse 2 was standing but ataxic (grade 4/5 gait deficit) and tetraparetic. Both horses had decreased tongue and tail muscle tone, and had normal spinal reflexes. Cerebrospinal fluid cytology was normal. Equine herpesvirus-1 testing was negative. Unassigned: Ticks were removed within 24 hours of pres...
Tyson R, Graham JP, Colahan PT, Berry CR.An 8-month-old miniature horse filly was presented for evaluation of severe rotational and angular limb deformities of the thoracic and pelvic limbs. On radiographic examination, complete ulnas and fibulas were identified. These findings are consistent with a condition previously described as a form of atavism. The term atavism is used to describe the reappearance of a trait or character that was seen in all earlier evolutionary specimens of a particular species, but has not been seen in recent ancestors. The atavistic traits of complete ulnas and fibulas have previously been described in Wels...
Elliott AR, Steffey EP, Jarvis KA, Marshall BE.The hypoxic pulmonary vasoconstrictor response to unilateral hypoxia was analyzed in pentobarbital anesthetized dogs (n = 5), miniature swine (n = 5), and ponies (n = 5). The left and right lungs (LL, RL) were separately ventilated with the LL exposed to inspired oxygen concentrations (CIO2) of 100%, 12%, 8% or 4%, while the RL always received a CIO2 = 100%. Pulmonary blood flow distribution was measured using 15 microns radioactive microspheres. LL PAO2, and percent pulmonary blood flow diversion (%FD) were calculated at each CIO2. At CIO2 of 4% there were significant differences (P greater t...
Khosravi AR, Nikaein D, Sharifzadeh A, Gharagozlou F.This study was carried out in order to isolate and identify the normal conjunctival fungal flora from Caspian miniature, Thoroughbred, Turkmen and Persian Arab breeds in Tehran, Iran. Methods: A total of seventy-two adult healthy horses were studied. Ocular samples were collected from right and left eyes by using sterile cotton swabs; samples were cultured on Sabouraud dextrose agar and incubated at 30°C for 7-10 days. Molds and yeasts were identified using macro and micro-morphological and physiological characteristics. Conclusions: Number of fungal colonies per eye varied between 0 and 123 ...
Lunn DP, Cuddon PA, Shaftoe S, Archer RM.In an investigation of 2 closely related Miniature Horses with a history of excessive sleepiness, depression and episodes of collapse, a diagnosis of narcolepsy was made on the basis of neurological examination and pharmacological testing. Further investigations included electroencephalographic examination (EEG), and analysis of protein content, cell count and monoamine metabolite concentrations of lumbosacral cerebrospinal fluid (CSF). There were no abnormalities noted in the EEGs, and no consistent changes in CSF neurotransmitter metabolites in the narcoleptic horses when compared with 3 nor...
Patrick DJ, Kiupel M, Gerber V, Carr EA.A 2-year-old female Miniature Horse that presented with a history of progressive weight loss, depression, and diarrhea was diagnosed at necropsy with a highly malignant abdominal neoplasm involving the left ovary, kidneys, adrenal glands, intestines, and various abdominal and thoracic lymph nodes. Microscopic examination of these masses revealed large pleomorphic cells that stained positive for vimentin and inhibin and negative for epithelial membrane antigen and placental alkaline phosphatase. Ultrastructural examination of the cells revealed a high nucleocytoplasmic ratio and indented euchro...
Butler J, Khan S, Scarzella G.Two young American miniature horses from the same farm were evaluated by a veterinarian due to presence of lethargy, anorexia, and cardiac arrhythmias. Both horses were treated aggressively with IV fluids and other supportive measures. The first horse died approximately 72 hr after the start of clinical signs and the second horse was humanely euthanized due to poor response to treatment. Oleander toxicosis was suspected based on the types of clinical signs present and due to several oleander plants and dried leaves present on the property. Oleander toxicosis was confirmed by the presence of ol...
Tee SY, Feary DJ.A 9-year-old Miniature Horse gelding infested with ticks (Ixodes holocyclus) was presented with flaccid motor paralysis causing recumbency. Neurological examination and other diagnostic tests did not identify an alternative aetiology, leading to a presumptive diagnosis of tick paralysis. The gelding was treated with tick antiserum and intensive supportive care. He made a gradual recovery over the 48 h following presentation and was discharged without further complications. This case report describes in detail the clinical signs and successful treatment of a Miniature Horse with flaccid paral...
Lee CD, Maxwell LK.In most species, large variations in body size necessitate dose adjustments based on an allometric function of body weight. Despite the substantial disparity in body size between miniature horses and light-breed horses, there are no studies investigating appropriate dosing of any veterinary drug in miniature horses. The purpose of this study was to determine whether miniature horses should receive a different dosage of flunixin meglumine than that used typically in light-breed horses. A standard dose of flunixin meglumine was administered intravenously to eight horses of each breed, and three-...
Pozor M, Conley AJ, Roser JF, Nolin M, Zambrano GL, Runyon SP, Kelleman AA, Macpherson ML.Recently, anti-Müllerian hormone (AMH) was validated as a reliable marker of testicular damage caused by various chemotherapy drugs in humans and in mice. In horses, the reference values of AMH concentrations in normal stallions, during different seasons of a year, have been recently reported. However, this hormone was not evaluated in subfertile or infertile stallions with testicular damage. Therefore, the objective of this study was to investigate the effects of experimentally induced testicular degeneration on the concentration of AMH in stallions. Severe but transient testicular degenerat...
Beeler-Marfisi J, Gallastegui Menoyo A, Beck A, König J, Hewson J, Bienzle D.Gelatinous marrow transformation, or serous atrophy of bone marrow fat, has been noted in livestock, laboratory animals, and wildlife in association with an inadequate plane of nutrition, inanition, or intoxication. This is a report of gelatinous marrow transformation and hematopoietic marrow atrophy in a 5-year-old miniature horse stallion. The horse had oral malformations leading to poor food assimilation and emaciation. A bone marrow biopsy obtained to investigate persistent anemia and leukopenia showed hematopoietic atrophy and replacement of fat with a granular extracellular substance, wh...
Gerding JC, Gilger BC, Montgomery SA, Clode AB.A 7-year-old, 153.0-kg American Miniature mare presented for evaluation of keratoconjunctivitis of the right eye (OD). A superior palpebral conjunctival mass and stromal keratitis were diagnosed. The incisional biopsy diagnosis was a presumptive corneal hemangiosarcoma. Transpalpebral enucleation was performed, and histopathologic evaluation confirmed angiosarcoma of the conjunctiva, cornea, and extraocular muscles. The horse developed progressive epistaxis and orbital swelling following surgery. A systemic workup was performed 3 months after enucleation, revealing regrowth within the orbit an...
Rosenstein DS, Schott HC, Stickle RL.This research article presents a case study of a one-month-old Miniature Horse colt that was diagnosed with a rare congenital condition called occipitoatlantoaxial malformation (OAAM). Case Presentation The foal was […]
Garcia-Lopez JM, Boudrieau RJ, Provost PJ.A 4-year-old castrated male Miniature Horse was evaluated because of severe right hind limb lameness of 5 days' duration. The diagnosis of craniodorsal luxation of the right coxofemoral joint was made by physical examination and radiographic imaging. Closed reduction was attempted but was unsuccessful. Surgical reduction was successfully performed, using toggle pin, synthetic capsular reconstruction, and trochanteric transposition techniques. No postoperative complications were observed. Follow-up 26 months after surgery revealed no recurrence of the luxation and no evidence of lameness. These...
Whitehair KJ, Adams SB, Toombs JP, Parker JE, Prostredny JM, Whitehair JG, Aiken SW.A llama, a miniature horse, and a miniature donkey with severe bilateral congenital flexural deformities of the metacarpophalangeal and metatarsophalangeal joints were treated successfully by arthrodesis with dynamic compression plating or external skeletal fixation. The flexor tendons were more taut than the suspensory ligaments and were transected. In the llama, the suspensory ligament was transected, and overcorrection caused ischemic necrosis of one distal limb and subluxation of the other fetlock joint. In the horse and donkey, the suspensory ligament was preserved and wedge osteotomy was...
McClure JT, Kobluk C, Voller K, Geor RJ, Ames TR, Sivula N.Four miniature foals admitted with signs of progressive nonresponsive abdominal pain and no fecal production had fecalith impaction of the small colon. Duration of clinical signs ranged from 10 hours to 5 days. Removal of the fecalith via small colon enterotomy was a successful treatment in all 4 cases. Miniature foals may be predisposed to fecalith impaction of the small colon. If a miniature foal has signs of progressive nonresponsive abdominal pain, fecalith impaction needs to be considered. Surgical correction may be required.
Cozens ER.A 4-year-old miniature horse experienced intermittent episodes of pyrexia, lethargy, and purulent vaginal discharge following dsytocia. Vaginal endoscopy and transrectal ultrasonography revealed a blind-ending vaginal cavity and distended uterus. Surgical treatment was declined and the mare was euthanized. Post-mortem examination confirmed the diagnosis of pyometra and vaginal adhesions. Un cheval miniature âgé de 4 ans a vécu des épisodes intermittents de pyréxie, de léthargie et de pertes vaginales purulentes après la dystocie. Une endoscopie vaginale et une échographie transrectale...
Malark JA, Nixon AJ, Haughland MA, Brown MP.The medical records of 17 horses with coxofemoral luxation were examined. Ponies and miniature horses were overrepresented. The mean age at the time of diagnosis was 7 years (range 1 month to 25 years). Seventy percent were female. Severe trauma, such as a fall or being kicked by another horse, was a common etiology. Thirty-five percent had other orthopedic injuries associated with the luxation. Closed reduction, with the use of a mechanically assisted calving device, was attained in 5 cases but reluxation occurred shortly afterward in 4 of these. Varying surgical techniques were used in 3 cas...
Easley JT, Freeman DE.To describe successful surgical treatment of bilateral mucocele in an American Miniature horse using a single bone flap to approach right and left paranasal sinuses simultaneously. Methods: Clinical report. Methods: A castrated 6-year-old American Miniature Horse with a bilateral mucocele of the paranasal sinuses. Methods: A single bilateral frontonasal sinus flap was used in a standing procedure to access the left and right conchofrontal sinuses simultaneously to remove the mucous contents and to establish permanent drainage into the nasal cavities. Results: The novel procedure used in this h...
Bergan T, Versland I.To be active, antimicrobials must reach the bacteria in the infectious foci in adequate concentrations. Direct measurements of levels in the various foci are difficult to perform, but a number of animal models with artificial extravascular foci have been developed. In many ways, the physiology of pigs resemble that of humans. Consequently, it was thought that pigs might also parallel humans in the handling of penicillins. General pharmacokinetics of ampicillin and flucloxacillin and the penetration of the substances to subcutaneously implanted teflon tistisue chambers were investigated. Ampici...
Moore BR, Abood SK, Hinchcliff KW.The medical records from 9 consecutive miniature horses (n = 5) and miniature donkeys (n = 4) with hyperlipemia (serum triglyceride concentration > 500 mg/dL) were reviewed. In all cases, hyperlipemia was a secondary complication of a primary systemic disease including septicemia, colitis, parasitism, esophageal obstruction, gastric impaction and rupture, fecalith, and pituitary adenoma. Therapy consisted of specific treatment for the primary disease, supportive care, and nutritional support. The mean time for resolution of hyperlipemia in cases requiring nutritional support (n = 6) was 7 days...
Hansen M, Knorr C, Hall AJ, Broad TE, Brenig B.The solute carrier family 26, member 2 (SLC26A2) gene belongs to a family of multifunctional anion exchangers. Mutations in the human SLC26A2 gene are associated with autosomal recessively inherited chondrodysplasias. Hence, we postulate that the equine SLC26A2 could be a candidate gene for conformational traits in horses. An equine BAC clone harboring the SLC26A2 gene was isolated. The complete 142,625 bp insert sequence of this clone was determined by transposon sequencing. Together with the SLC26A2 gene the BAC clone contains four genes, i.e. the macrophage colony stimulating factor 1 recep...
Cargile JL, MacKay RJ, Dankert JR, Skelley L.A monoclonal antibody (MAB) against equine tumor necrosis factor-alpha (Eq TNF) was used to investigate the role of TNF in cytokine, eicosanoid, and metabolic responses of Miniature Horses given endotoxin. Plasma concentrations of interleukin 6 (IL-6), lactate, thromboxane A2 metabolite, and prostacyclin metabolite (6-keto-PGF1 alpha) were measured in 10 Miniature Horses given 0.25 microgram of lipopolysaccharide (LPS; Escherichia coli O55:B5)/kg of body weight. Five horses were given Eq TNF MAB and 5 were given isotype-matched MAB as control. All horses were given 1.86 mg of antibody/kg by IV...
Wobeser BK.During a widespread anthrax outbreak in Canada, miniature horses were vaccinated using a live spore anthrax vaccine. Several of these horses died from an apparent immune-mediated vasculitis temporally associated with this vaccination. During the course of the outbreak, other miniature horses from different regions with a similar vaccination history, clinical signs, and necropsy findings were found. Vaccin contre l’anthrax associé à la mort de chevaux miniatures. Durant une vaste éclosion d’anthrax au Canada, des chevaux miniatures ont été vaccinés en utilisant un vaccin à base de sp...
Dunkel B, Buonpane A, Chang YM.Clinical impression suggests that some gastrointestinal lesions are more common in certain horse types. The study tested the hypothesis that relative prevalence of acute gastrointestinal lesions differs between equid types. In a retrospective caseâ€"control study, records (2010â€"2015) were reviewed for equids with acute gastrointestinal disease. Signalment, details of gastrointestinal lesions and diagnoses were recorded. Animals were categorised as miniature type, pony, Arabian, light breed or draft type. Exclusion criteria were no recorded breed/size/diagnosis, age less than one year a...
