Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Fenger CK, Granstrom DE, Gajadhar AA, Williams NM, McCrillis SA, Stamper S, Langemeier JL, Dubey JP.Sarcocystis sp. sporocysts isolated from eight feral opossums (Didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (Melopsittacus undulatus), 14 wild-caught sparrows (Passer domesticus), one wild-caught slate-colored Junco (Junco hyemalis) and five weanling horses (Equus caballus). All budgerigars died within 5 weeks post inoculation (wpi). Histologic examination revealed meronts within the pulmonary epithelia and typical Sarcocystis falcatula sarcocysts developing in the leg muscles. Sparrows were euthanized 13 and 17 wpi and their carcasses were fed to four labora...
Kaneene JB, Ross WA, Miller R.A prospective study was designed to document the frequencies of equine health problems in the state of Michigan, USA. A total of 2469 horses from a random sample of 138 equine operations were monitored in the study in two 12-month periods: 1992-1993 and 1993-1994. All the major breeds of horses in the state were proportionately represented in the sample. Using weighted annual incidence densities as measures of disease frequencies, the 10 most frequently observed groups of health problems were (from most to least frequent) leg lameness, dermatological problems, respiratory problems, hoof and fo...
Griffin LV, Gibeling JC, Gibson VA, Martin RB, Stover SM.Experiments and analyses were performed to determine the cause of a nonlinear force-deflection response observed in four-point flexural fatigue of beams of cortical bone machined from the mid-diaphysis of the equine third metacarpus. Observable grooves which formed on the beam surface at supports and load noses were found to be the primary cause of the nonlinearity. An additional geometric nonlinearity at large deflections revealed by finite element modeling may be minimized by using the smallest diameter supports and load noses recommended in ASTM 790. However, frictional constraint of the be...
O'Sullivan JD, Allworth AM, Paterson DL, Snow TM, Boots R, Gleeson LJ, Gould AR, Hyatt AD, Bradfield J.In September, 1994, an outbreak of severe respiratory disease affected 18 horses, their trainer, and a stablehand in Queensland, Australia. Fourteen horses and one human being died. A novel virus was isolated from those affected and named equine morbillivirus (EMV). We report a case of encephalitis caused by this virus. Results: A 35-year-old man from Queensland had a brief aseptic meningitic illness in August, 1994, shortly after caring for two horses that died from EMV infection and then assisting at their necropsies. He then suffered severe encephalitis 13 months later, characterised by unc...
Polzer J, Slater MR.A case-control study was conducted at the Texas Veterinary Medical Center between January 1, 1986 and December 31, 1991. Logistic regression was used to assess age, breed, sex, and seasonality as risk factors for equine laminitis. There were 70 acute cases, 183 chronic cases, and 779 controls. No statistical association was found between age, breed, sex, or seasonality and the diagnosis of acute laminitis. For chronic cases, the estimated odds ratio was statistically significant for age (OR = 1.05, 95% CI (1.02, 1.08)) and for the diagnosis of laminitis in the third quarter of the year (OR = 2...
Glatthaar R.In April 1996 an attack of black flies (Diptera, Simuliidae) to horses was observed in the region of Basle, Switzerland. Females of Simulium erythrocephalum and Simulium ornatum were involved in this attack, part of them had taken a blood meal. For S. ornatum this is the first record in Switzerland that this species takes blood meals on horses.
Platt D, Wright IM.The history, clinical features, radiological findings, treatment and outcome of 15 horses with chronic tenosynovitis of the carpal extensor tendon sheaths are reported. The condition was seen most commonly in horses used for jumping and penetration of the tendon sheaths by thorns was the most common aetiology. Treatment involved surgical resection of the hyperplastic synovial membrane, and adhesions within the tendon sheath, with primary closure. When combined with early postoperative physiotherapy this was found to be an effective method of treatment. All horses in this series were not lame a...
Adams MR, Register TC, Golden DL, Wagner JD, Williams JK.Although estrogen replacement therapy is associated with reduced risk of coronary heart disease and reduced extent of coronary artery atherosclerosis, the effects of combined (estrogen plus progestin) hormone-replacement therapy are uncertain. Some observational data indicate that users of combined hormone replacement consisting of continuously administered oral conjugated equine estrogens (CEE) and oral sequentially administered (7 to 14 days per month) medroxyprogesterone acetate (MPA) experience a reduction in risk similar to that of users of CEE alone. However, the effects of combined, con...
Tyler-McGowan CM, Hodgson JL, Hodgson DR.To determine the regional incidence and effectiveness of treatment of failure of passive transfer (FPT) in foals. Methods: A study of disease incidence. Methods: Eighty-eight foals and 57 mares from four studs in the practice area of the Rural Veterinary Centre were tested. Methods: Foals were tested for their serum IgG and total serum protein (TSP) concentration within the first 72 hours of life. Colostrum was collected from mares and specific gravity determined. FPT and partial failure of passive transfer (PFPT) of immunoglobulins was diagnosed when serum IgG concentrations were < 4 g/L and ...
Reubel GH, Studdert MJ.Based on sequence homology with human adenovirus 2 (HAdV2), the hexon gene of equine adenovirus 1 (EAdV1) was identified. HindIII restriction fragments containing the hexon and other viral genes were cloned into the plasmids pUC19 and pBlueScript SK(-) and sequenced. The nucleotide sequence of the hexon gene was completely determined and partial sequence data were obtained for seven other EAdV1 genes. Amino acid (aa) sequence comparison with published adenovirus (AdV) proteins identified the genes for the IIIa, penton, pVII, PVI, 23K proteinase, DNA binding and 100K proteins. The eight EAdV1 g...
Cirak VY, Hermosilla C, Bauer C.Quantitative faecal and post-mortem examinations of 16 ponies, 1 to 2 1/2 years of age, originating from 3 farms in northern Germany were performed in February 1995 to determine the prevalence and intensity of gastrointestinal parasites in these animals. A total of 33 species of metazoan parasites was recovered: three tapeworm species (Anoplocephala perfoliata, A. magna, Paranoplocephala mamillana), Strongylus vulgaris, S. edentatus, small strongyles (including four Triodontophorus spp., Craterostomum acuticaudatum and 19 cyathostome species), Oxyuris equi, Parascaris equorum, Habronema majus ...
Hendrickson DA.The determination of poor performance in the young or unproven horse can be a difficult experience for the practitioner. This article describes an incremental exercise test that may be helpful in determining the cause of poor performance in horses when a complete physical examination and a lameness examination fail to elucidate the causes of poor performance. Included are values from normal yearling and 2-year-old horses that have undergone the incremental exercise test.
Marsh AE, Barr BC, Madigan J, Lakritz J, Nordhausen R, Conrad PA.Neosporosis was diagnosed in an 11-year-old Quarter Horse gelding with clinical signs and diagnostic test results compatible with equine protozoal myeloencephalitis (EPM). Presumptive postmortem diagnosis of EPM attributable to Sarcocystis neurona infection is generally made on the basis of detecting an antibody titer to S neurona in the CSF or characteristic histologic lesions, even when parasites have not been specifically identified. Neosporosis was confirmed in the horse described here by use of immunohistochemical examination, in vitro culturing, and ultrastructural and molecular characte...
Foreman JH.Metabolic causes of exercise intolerance can be subtle and difficult to document in horses. Because of increased metabolic rate in exercising muscle, most metabolic causes of exercise intolerance are clinically manifested by muscle abnormalities such as ER. Newer causes of ER are being documented by current research and are summarized in the article on muscular causes of equine exercise intolerance. Endocrine causes of exercise intolerance have been poorly documented, but recent work has shown the detrimental effects of hypothyroidism on exercise tolerance in horses. Many metabolic manifestati...
Mitten LA.Exercise intolerance, due to cardiovascular disease in horses, may be caused by cardiac arrhythmias, valvular regurgitation, congenital abnormalities, myocardial dysfunction, pericardial disease, and vascular thrombosis. The most common cardiovascular cause of exercise intolerance in horses is atrial fibrillation. Cardiovascular abnormalities such as cardiac arrhythmias or murmurs, however, are common in athletic horses and are not always associated with exercise intolerance. Use of an electrocardiography (during rest and exercise) and echocardiography may be necessary to better determine the ...
The Journal of physiologyDecember 1, 1996
Volume 497 ( Pt 2), Issue Pt 2 349-364 doi: 10.1113/jphysiol.1996.sp021773
Hanna WJ, Tsushima RG, Sah R, McCutcheon LJ, Marban E, Backx PH.1. The Na+ channel mutation associated with equine hyperkalaemic periodic paralysis (HPP) affects a highly conserved phenylalanine residue in an unexplored region of the alpha-subunit. This mutation was introduced into the rat skeletal muscle Na+ channel gene at the corresponding location (i.e. F1412L) for functional expression and characterization in Xenopus oocytes. 2. In comparison with wild-type (WT) channels, equine HPP channels showed clear evidence for disruption of inactivation: increased time-to-peak current, slowed rates of whole-cell current decay, significant increases in sustained...
Jarvis GE, Evans RJ, Heath MF.We have shown previously that endotoxin induces platelet aggregation in equine heparinised whole blood in a platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) dependent manner. ADP is an agonist of platelets and is present in platelet dense granules with ATP in high concentrations. An investigation was carried out to establish whether endotoxin-induced platelet activation was associated with release of platelet ATP and ADP. ADP-scavenging enzyme systems significantly inhibited endotoxin-induced aggregation. Plasma levels of adenine nucleotides were measured using ...
Lea RG, Bolton AE.Commercial preparations of equine chorionic gonadotrophin (eCG) and extracts of horse placenta taken at 80 days gestation were incorporated into mixed lymphocyte culture and mitogen stimulation assays of horse peripheral blood mononuclear cells. A dose-related inhibition of lymphocyte proliferation, indicative of immunosuppressive activity, was observed in both systems, both with commercial eCG preparations and tissue extracts. Negligible inhibitory activity was observed with an extract of term placenta. The inhibitory activity of the placental samples was not related to their eCG content as m...
Lord CC, Venter GJ, Mellor PS, Paweska JT, Woolhouse ME.African horse sickness (AHS) and equine encephalosis (EE) viruses are endemic to southern Africa. AHS virus causes severe epidemics when introduced to naive equine populations, resulting in severe restrictions on the movement of equines between AHS-positive and negative countries. Recent zoning of South Africa has created an AHS-free zone to facilitate equine movement, but the transmission dynamics of these viruses are not fully understood. Here, we present further analyses of serosurveys of donkeys in South Africa conducted in 1983-5 and in 1993-5. Age-prevalence data are used to derive estim...
Kelly AP, Jones RT, Gillick JC, Sims LD.An outbreak of nervous disease in Standardbred horses occurred near Bendigo, in south-eastern Australia, in October 1980. Over a two week period 11 horses in four training stables were affected with gait abnormalities, depression and recumbency. Eight of the 11 died. The results of an investigation implicated Clostridium botulinum toxin as the cause. The toxin was food-borne as a contaminant of oaten chaff.
Middlebrooks B, McCue P, Nelson B, May E, Divine C, Barton C, Conley A.Disorders of sexual development (DSD) are associated with atypical chromosomal, gonadal, or phenotypic sex. It is likely that the number of cases of DSD are underestimated in the equine population. Monorchidism in the horse is very rare. This case report describes the clinical assessment of a phenotypic mare with stallion-like behavior which led to the diagnosis of a DSD. A 4-year-old Quarter Horse mare presented in good body condition, with normal external genitalia for a mare, and normal mammary glands with two bilaterally symmetric teats. No uterus, cervix, or gonads were detected on transr...
van den Ingh TS, Hartman EG, Bercovich Z.A Leptospira interrogans serogroup australis serovar lora infection in a stud farm is reported. During three successive years (1984-1986) clinical leptospirosis with a severe often rapid, fatal course was seen in 12 foals. Clinical examination revealed severe respiratory distress, depression and pyrexia. Other symptoms were diarrhea (2), jaundice (1), and an unsteady gait (1). Morphological characteristics of the disease were massive pulmonary haemorrhage and haemorrhagic-thrombotic or extracapillary glomerulonephritis with tubulonephrosis and interstitial oedema. In most foals high or increas...
Hunter JO.Irritable bowel syndrome (IBS) in man is not a single entity but has several causes. One of the most common forms has similarities with colic and laminitis in horses. Undigested food residues may pass from the small intestine into the colon where bacterial fermentation produces chemicals that lead to disease. In horses the consequences may be disastrous, but in healthy humans such malabsorption may not be harmful. After events such as bacterial gastroenteritis or antibiotic treatment, an imbalance of the colonic microflora with overgrowth of facultative anaerobes may arise, leading to malferme...
Höglund N, Koho N, Rossi H, Karttunen J, Mustonen AM, Nieminen P, Rilla K, Oikari S, Mykkänen A.Extracellular vesicles (EVs) are membrane-bound particles that engage in inflammatory reactions by mediating cell-cell interactions. Previously, EVs have been isolated from the bronchoalveolar lavage fluid (BALF) of humans and rodents. The aim of this study was to investigate the number and size distribution of EVs in the BALF of asthmatic horses (EA, = 35) and healthy horses ( = 19). Saline was injected during bronchoscopy to the right lung followed by manual aspiration. The retrieved BALF was centrifuged twice to remove cells and biological debris. The supernatant was concentrated and EVs w...
Norrdin RW, Bay BK, Drews MJ, Martin RB, Stover SM.An overload arthrosis occurs consistently in the palmar region of the metacarpal condyle of the equine fetlock (metacarpophalangeal) joint characterized by subchondral bone sclerosis, devitalization and mechanical failure leading to collapse of the overlying articular cartilage. Samples were selected of joints with mild, moderate, and severe subchondral sclerosis, in which cartilage collapse had not yet occurred. An additional group that had severe sclerosis with focal rarefaction suggesting impending collapse was also studied (n=5/group). Parasagittal slices were milled to 2.0 mm thickness an...
Mykkänen AK, Koho NM, Reeben M, McGowan CM, Pösö AR.Polymorphisms in human lactate transporter proteins (monocarboxylate transporters; MCTs), especially the MCT1 isoform, can affect lactate transport activity and cause signs of exercise-induced myopathy. Muscles express MCT1, MCT4 and CD147, an ancillary protein, indispensable for the activity of MCT1 and MCT4. We sequenced the coding sequence (cDNA) of horse MCT4 for the first time and examined polymorphisms in the cDNA of MCT1, MCT4 and CD147 of 16 healthy horses. To study whether signs of myopathy are linked to the polymorphisms, biopsy samples were taken from 26 horses with exercise-induced...
Muirhead T, McClure JT, Bourque A, Pack L.A lesion in the cervical region of a 14-month-old Belgian gelding with severe ataxia was suspected. Necropsy revealed symmetric focal cartilage defects compatible with osteochondrosis of the occipital condyles and atlanto-occipital dysplasia. To our knowledge this is the first equine report of symmetrical osteochondrosis of the occipital condyles causing neurologic signs.
Winder NC, Grünig G, Hermann M, von Fellenberg R.The concentration of soluble fibrinogen derivatives (SFD) and protease and procoagulant activities were determined in cell-free supernatants of equine respiratory secretions obtained from horses with chronic pulmonary disease. The concentration of neutrophils was estimated from direct smears of the secretions. Lung specimens and smears of the secretions were evaluated for the presence of fibrin or fibrinogen by use of immunohistochemical methods. Thirty-five of 80 specimens tested contained SFD. Respiratory secretions from horses with moderate or severe chronic pulmonary disease contained SFD ...
Ziemer EL, Parker HR, Carlson GP, Smith BP, Ishizaki G.An 11-year-old Quarter Horse mare and a 2-year-old Quarter Horse colt with clinical diagnoses of renal tubular acidosis (RTA) were donated to the University of California Veterinary Medical Teaching Hospital. A series of diagnostic tests was performed in an attempt to characterize the type and cause of RTA in these horses. Endogenous creatinine clearance and sodium sulfanilate clearance were within reference ranges; thus, no abnormality of glomerular function was detected. To assess renal tubular function in response to acid loading, each horse was given 0.1 g of NH4Cl/kg of body weight via na...
Morley PS, Traub-Dargatz JL, Benedict KM, Saville WJ, Voelker LD, Wagner BA.Equine protozoal myeloencephalitis (EPM) is a serious and often fatal neurologic disease of horses, but few studies have investigated risk factors. Objective: To evaluate operation- and individual-level factors associated with likelihood of the occurrence of EPM. Methods: Data were collected as part of a study of the US equine industry from 1,178 operations representing 83.9% of horses and 51.6% of operations with > or =3 horses in 28 states. Methods: Probability-based sampling was used to enroll representative operations in a cross-sectional study. Interviews were conducted to collect info...
Cranley JJ, McCullagh KG.The hearts and aortas of 2076 unselected horses of all ages were examined immediately after slaughter. Focal zones of fibrosis, observed in the myocardium of 14.3 per cent of hearts examined, were found in both atria and ventricles and were unrelated to age. Microscopically the majority of lesions involved myocardial fibre lysis and replacement fibrosis, although acute infarction was present in some cases. Intramyocardial arterioles in or adjacent to the lesions exhibited occlusive arteriosclerotic changes whereas those elsewhere remained patent. The evidence strongly suggests that the myocard...
Rugh KS, Garner HE, Hatfield DG, Miramonti JR.The response of coronary collaterals in nine ponies subjected to repeated reversible occlusions (2 min duration, 30 min interval) of the left anterior descending coronary artery was studied at rest. Each pony was instrumented with a Doppler flowmeter and hydraulic cuff occluder around the left anterior descending coronary artery, left ventricular subendocardial sonomicrometers, and a left ventricular micromanometer. Initial occlusions increased end diastolic myocardial segment length by 3% and decreased segment systolic shortening, stroke work, and velocity of shortening by 103%, 95%, and 79% ...
Gabel AA.A prospective study of the diagnostic results on 25 previously untreated, slightly lame Standardbred horses showed that manipulative tests are of some help in diagnosis. The lameness of each horse was diminished or the horse went lame on the opposite limb after being given an injection of anesthetic in the cunean bursa, and lameness improved more when local anesthetic was injected in the distal intertarsal and tarsometatarsal articulations. In four horses, lesions of the distal articulation of the hock were evident on radiography.
Metz GE, Ocampos GP, Serena MS, Gambaro SE, Nosetto E, Echeverría MG.To perform genetic analysis of the ORF5 of equine arteritis virus (EAV) may provide new insights into the genetic evolution and origin of the Argentinean EAV sequences. Methods: A total of 76 sequences were analyzed by neighbor joining (NJ), maximum parsimony and maximum likelihood algorithms. The analysis of the selective pressures was performed using the Tajima's test. Results: The trees showed similar topologies. Two clades were identified: the first clade was formed by strains isolated mainly from a donkey, whereas the second clade presented four large groups from different geographic regi...
Steinfort S, Röcken M, Vogelsberg J, Failing K, Staszyk C.Equine periodontal disease in horses has long been recognized as a painful disease, leading to a poor condition. The disease is widespread and attracts growing attention in equine dental medicine. The understanding of the underlying etiological and pathological mechanisms of equine periodontal disease is necessary to develop effective prophylactic and treatment options. As a first step, a thorough description of the histological features of the healthy equine gingiva is required. Specimens were taken from six horses (3 mares, 3 geldings, age: 0.5-26 years). The animals were euthanized for reas...
Cohen ND.Understanding the epidemiology of equine colic is directly relevant to the management of individual horses with colic. In this article, the epidemiology of colic is reviewed with emphasis on epidemiologic studies that have identified specific factors associated with increased risk of colic and epidemiologic studies that are designed to predict the need for surgery and prognosis in horses with colic. Despite the magnitude of the problem of equine colic, much remains to be learned about the epidemiology of this disease.
Annandale A, Stroehle RM, Schulman ML, Sibeko-Matjila KP, Fosgate GT, Handler J, Vemming DC, Clift SJ.Persistent breeding-induced endometritis (PBIE) or delayed uterine clearance (DUC) are major causes of mare subfertility. Oxytocin and its receptor are thought to play significant roles in the pathogenesis of DUC but the specific roles of oxytocin receptor (OR) distribution and gene expression remain undefined. In this study both OR distribution and gene expression in the endometrium, myometrium and cervix during both luteal and non-luteal phases in non-pregnant mares (n = 27) of differing age (young: 2-9 years, n = 17; old: > 10 years, n = 10) and endometrial biopsy score were ...
Schmidt GM, Krehbiel JD, Coley SC, Leid RW.Equine eyes (368) were examined clinically and histologically for abnormalities associated with the presence of ocular microfilariae of naturally occurring Onchocerca sp infection. Forty of the eyes had microfilariae in the conjunctiva, but distinguishing clinical abnormalities were not associated with their presence. In 1 horse with ocular microfilariae that was treated with diethylcarbamazine daily for 2 weeks, ocular tissue samples were obtained before, during, and after the horse was treated, and the samples were compared histologically. During treatment of the horse, microfilariae apparen...
Wylie CE, Shaw DJ, Fordyce FM, Lilly A, McGorum BC.Equine grass sickness (EGS) remains a frequently fatal disease of equids in Britain. Since previous investigations of signalment- and meteorology-related risk factors for EGS have yielded some conflicting data, further investigation is warranted. Objective: To identify signalment- and meteorology-related risk factors for EGS in Scotland. Methods: Retrospective time-matched case-control study. Methods: This study was undertaken using data for 455 EGS cases and 910 time-matched controls that were referred to the Royal (Dick) School of Veterinary Studies, and average UK Meteorological Office weat...
Davidson AJ, Edwards GB, Proudman CJ, Cripps PJ, Matthews JB.The aim of this study was to investigate cytokine expression patterns in the large intestinal mucosa of horses, particularly in diseases associated with inflammation. Many cases of equine colitis remain without a definitive diagnosis and survival rates are poor. In humans, colitis is associated with increased expression of pro-inflammatory cytokines. To examine if similar responses occur in horses, we investigated il -2, il -4, il -5, il -10, tnfalpha, ifngamma and tgfbeta messenger rna expression in large intestinal mucosa. Samples were obtained from animals with large intestinal disease (n=1...
Di Meo GP, Neglia G, Perucatti A, Genualdo V, Iannuzzi A, Crocco D, Incarnato D, Romano G, Parma P, Iannuzzi L.Gonadal dysgenesis and heterosexual conditions are often associated with sex chromosome abnormalities. In this study we report on 2 cases of abnormal sex development involving numerical sex chromosome aberrations in both horse and sheep. A 17-month-old Standardbred filly was sent to an equine fertility centre as an embryo donor due to its reduced size, being much smaller than a racehorse filly of the same age, which excluded it from an athletic career. External genitalia were clinically normal but manual palpation of the reproductive tract showed the presence of a small underdeveloped uterus a...
Bellone RR.Advances in equine genetics and genomics resources have enabled the understanding of some inherited ocular disorders and ocular manifestations. These ocular disorders include congenital stationary night blindness, equine recurrent uveitis, multiple congenital ocular anomalies, and squamous cell carcinoma. Genetic testing can identify horses with or at risk for disease and thus can assist in clinical management. In addition, genetic testing can identify horses that are carriers and thus can inform breeding decisions. Use of genetic tests in management and breeding decisions should aid in reduci...
Benninger MI, Deiss E, Ueltschi G.We describe the clinical findings and radiographic abnormalities of a horse with a bipartite distal phalanx and a bipartite navicular bone of the right forelimb. Associated findings including suspected keratoma and degenerative joint disease of the distal interphalangeal joint are described and possible etiologies are discussed.
Clegg PD, Coughlan AR, Carter SD.Matrix metalloproteinases (MMPs) are the main enzymes involved in connective tissue turnover. Regulation of MMPs is achieved by controlling production, activation of the pro-enzymes together with the presence of inhibitors, such as, tissue inhibitors of metalloproteinases (TIMPS). The presence of TIMPs in equine synovial fluid was assessed by the ability of the fluid to inhibit equine MMP-9 activity using a gelatin degradation ELISA. The cellular source of the TIMPs was determined using culture supernatants of resident articular cells (chondrocytes and synovial fibroblasts) and invading inflam...
Cuervo-Arango J, Claes AN, Stout TAE.Equine embryos tolerate an unusually large degree of negative uterine asynchrony (recipient mare up to 5 days behind the donor mare). By contrast, positive asynchrony of more than 2 days results in a high incidence of early embryonic loss (EEL). Day 8 embryos range in diameter from approximately 130-1300 μm, with embryos smaller than 300 μm reported to suffer an increased incidence of EEL. However, it is not known whether this reduced viability is due to intrinsically poor embryo quality, or to inadvertent recipient uterine stage-embryo (positive) asynchrony. To examine whether small emb...
Frederico LM, Jones SL, Blikslager AT.To identify factors associated with development of small colon impaction in horses and with selection of medical versus surgical treatment and to determine the prognosis for affected horses following medical or surgical management. Methods: Retrospective case series. Methods: 44 horses with primary impaction of the small colon. Methods: Medical records were reviewed for signalment, history, clinical findings, treatment (medical vs surgical), hospitalization time, and outcome. For comparison purposes, the same information was collected for 83 horses with primary impaction of the large colon. Re...
