Abnormalities In Horses Research Articles

Ocular findings in Quarter Horses with hereditary equine regional dermal asthenia

To compare ocular structures of Quarter Horses homozygous for hereditary equine regional dermal asthenia (HERDA) with those of Quarter Horses not affected by HERDA (control horses) and to determine the frequency of new corneal ulcers for horses with and without HERDA during a 4-year period. Cohort study of ocular structures and retrospective case series of horses with and without HERDA. The cohort portion of the study involved 10 Quarter Horses with HERDA and 10 Quarter Horses without HERDA; the retrospective case series involved 28 horses with HERDA and 291 horses without HERDA. Ophthalmic examinations, Schirmer tear tests, tonometry, corneal pachymetry, histologic examinations, and scanning electron microscopy (SEM) were performed in cohorts of Quarter Horses with and without HERDA. Records were reviewed to determine the incidence of corneal ulcers in horses with and without HERDA during a 4-year period. Corneal thickness of horses with HERDA was significantly less than that of control horses, but tear production of horses with HERDA was significantly greater than that of control horses. Results of SEM revealed zones of disorganized, haphazardly arranged collagen fibrils in corneas of horses with HERDA that were not evident in corneas of control horses. The incidence of corneal ulcers was significantly greater for horses with HERDA than for horses without HERDA during the 4-year period. Alterations in corneal thickness, arrangement of collagen fibers, and incidence of corneal ulcers indicated that abnormalities in horses with HERDA were not limited to the skin.

Evaluation of a protocol for fast localised abdominal sonography of horses (FLASH) admitted for colic

The aim of this prospective study was to establish a protocol for fast localised abdominal sonography of horses (FLASH) admitted for colic. The FLASH protocol was then presented to clinicians without extensive ultrasound (US) experience to determine whether they could learn to use it in less than 15 min. The clinical subjects comprised 36 horses that had been referred for colic over a 2 month period. Each horse was examined at admission and FLASH findings at seven topographical locations were compared to serial clinical examinations, surgical and non-surgical outcomes, or with post-mortem reports. FLASH was able to show free abdominal fluid and abnormal intestinal loops, with a mean time of 10.7 min required to complete the protocol. The positive and negative predictive values of requirement for surgery of dilated turgid small intestinal loops using FLASH were 88.89% and 81.48%, respectively. The results suggested that FLASH is a technique that can be used in an emergency setting by veterinarians without extensive US experience to detect major intra-abdominal abnormalities in horses with colic.

A Survey of Equine Oral Pathology

Dental abnormalities in horses can lead to weight-loss, poor performance, pain, behavioral abnormalities, and illness. Despite this impact, the occurrence and type of dental disease in horse populations is infrequently reported in veterinary medicine. The purpose of this cross-sectional survey of horses presented for slaughter at a processing plant in Western Canada was to measure the prevalence of equine oral abnormalities, examine associations between the most common abnormalities, and consider the relationship between the age of horse and types of abnormalities observed. The horses used in this research consisted of a variety of ages, breeds, body conditions, and origins. Horses ranged in age from 18-months to 30-years (median = 11-years). The most common oral pathologies included sharp edges, buccal abrasions, calculus, lingual ulcers, gingival recession, periodontal pockets, ramps, and waves. Several types of pathology were strongly associated with other dental disorders. The prevalence of periodontal pockets, gingival recession, and waves was highest in older horses.

Dental abnormalities in horses

Dental abnormalities in horses

Molecular Evidence for Persistence ofAnaplasma phagocytophilumin the Absence of Clinical Abnormalities in Horses after Recovery from Acute Experimental Infection

Anaplasma phagocytophilum infects several mammalian species, and can persist in sheep, dogs, and calves. However, whether this organism persists in horses or induces long-term clinical abnormalities is not known. To evaluate whether A. phagocytophilum can persist in horses and to document clinical findings for 3 months after complete recovery from acute disease. Five clinically normal adult horses that had recovered spontaneously from experimentally induced acute disease caused by a Swedish equine isolate of A. phagocytophilum. Horses were monitored for up to 129 days post inoculation (PI) by daily clinical examination and at least alternate day blood sampling for evidence of A. phagocytophilum on polymerase chain reaction (PCR) and blood smears. All horses were euthanized and underwent postmortem examination. All horses were periodically PCR positive after recovery from acute infection. Before day 66 PI 2 horses were persistently PCR negative whereas 3 horses were intermittently PCR positive. Subsequently, 4 of 5 horses were intermittently PCR positive, particularly after stress mimicking interventions. One animal was positive immediately before postmortem examination. Clinical abnormalities related to persistence of anaplasma were not observed. No specific changes were found at postmortem examination, and all sampled tissues from all horses were negative on PCR for A. phagocytophilum. Infection with A. phagocytophilum can persist in the horse for at least 129 days. However, the continued presence of the organism is not associated with detectable clinical or pathological abnormalities.

Assessing Chromosome Abnormalities in Horses with Infertility or Congenital Abnormalities

Assessing Chromosome Abnormalities in Horses with Infertility or Congenital Abnormalities

Clinical and scintigraphic findings in horses with a bone fragility disorder: 16 cases (1980–2006)

To describe clinical and scintigraphic abnormalities in horses with a bone fragility disorder. Retrospective case series. 16 horses with scintigraphic evidence of multiple sites of increased radiopharmaceutical uptake (IRU). Procedures-Medical records were reviewed for information on signalment; history; clinical, clinicopathologic, and diagnostic imaging findings; and treatment. Follow-up information was obtained through telephone interviews with owners. Horses ranged from 4 to 22 years old; there were 8 castrated males and 8 females. Foci of IRU most commonly involved the scapulae, ribs, sternebrae, sacral tubers, ilia, and cervical vertebrae. Most horses were examined because of chronic intermittent (n = 10) or acute (6) lameness involving a single (10) or multiple (6) limbs that could not be localized by means of regional anesthesia. Cervical stiffness (n = 3), scapular bowing (3), swayback (3), and ataxia (1) were also seen in more advanced cases. Signs of respiratory tract disease and exercise intolerance were evident in 4 horses. Ultrasonographic or radiographic evidence of bone remodeling or degeneration was seen in 19 of 33 affected bones. Histologic examination of bone biopsy specimens revealed reactive bone. Improvement was initially seen with conservative treatment in some horses, but the condition worsened in all horses, and 11 horses were euthanized within 7 years. Results suggested that horses may develop a bone fragility disorder characterized clinically by an unlocalizable lameness and scintigraphically by multiple sites of IRU involving the axial skeleton and proximal portion of the appendicular skeleton.

MAGNETIC RESONANCE IMAGING FEATURES OF PROXIMAL METACARPAL AND METATARSAL INJURIES IN THE HORSE

Magnetic resonance (MR) imaging abnormalities in horses with lameness localized to the proximal metacarpal or metatarsal region have not been described. To accomplish that, the medical records of 45 horses evaluated with MR imaging that had lameness localized to either the proximal metacarpal or metatarsal region were reviewed. Abnormalities observed in the proximal suspensory ligament or the accessory ligament of the deep digital flexor tendon included abnormal high signal, enlargement, or alteration in shape. Twenty-three horses had proximal suspensory ligament desmitis (13 hindlimb, 10 forelimb). Sixteen horses had desmitis of the accessory ligament of the deep digital flexor tendon. One horse had desmitis of the proximal suspensory ligament and the accessory ligament of the deep digital flexor tendon on the same limb and one horse had desmitis of the proximal suspensory ligament on one forelimb and desmitis of the accessory ligament of the deep digital flexor tendon on the other forelimb. Four horses did not have abnormalities in the proximal suspensory ligament or accessory ligament of the deep digital flexor tendon. Eighty percent of horses with forelimb proximal suspensory ligament desmitis and 69% of horses with hindlimb proximal suspensory ligament desmitis returned to their intended use. Sixty-three percent of horses with desmitis of the accessory ligament of the deep digital flexor tendon were able to return to their intended use. MR imaging is a valuable diagnostic modality that allows diagnosis of injury in horses with lameness localized to the proximal metacarpal and metatarsal regions. The ability to accurately diagnose the source of lameness is important in selecting treatment that will maximize the chance to return to performance.

Clinical and clinicopathologic variables in adult horses receiving blood transfusions: 31 cases (1999–2005)

To determine clinical and clinicopathologic abnormalities in horses administered a blood transfusion and evaluate effects of blood transfusion on these variables. Retrospective case series. 31 adult horses that received > or = 1 blood transfusion. Procedures-Medical records of horses receiving a blood transfusion were reviewed to obtain clinical findings, laboratory test results before and after transfusion, adjunctive treatments, transfusion type and volume, response to transfusion, results of donor-recipient compatibility testing, adverse reactions, and outcome. 31 horses received 44 transfusions for hemorrhagic anemia (HG; n = 18 horses), hemolytic anemia (HL; 8), or anemia attributable to erythropoietic failure (EF; 5). Tachycardia and tachypnea were detected in 31 of 31 (100%) and 22 of 31 (71%) horses, respectively, before transfusion. The PCV and hemoglobin concentration were less than the reference range in 11 of 18 horses with HG, 8 of 8 horses with HL, and 5 of 5 horses with EF. Hyperlactatemia was detected in 16 of 17 recorded values before transfusion. Heart rate, respiratory rate, and PCV improved after transfusion, with differences among the types of anemia. Seventeen (54%) horses were discharged, 9 (29%) were euthanized, and 5 (16%) died of natural causes. Adverse reactions were evident during 7 of 44 (16%) transfusions, varying from urticarial reactions to anaphylactic shock. Abnormalities in clinical and clinicopathologic variables differed depending on the type of anemia. Colic, cold extremities, signs of depression, lethargy, tachycardia, tachypnea, low PCV, low hemoglobin concentration, and hyperlactatemia were commonly detected before transfusion and resolved after transfusion.

Correlations between exercising arterial blood gas values, tracheal wash findings and upper respiratory tract abnormalities in horses presented for poor performance

There are limited data on the correlations between arterial blood gas (ABG) values, tracheal wash (TW) cytology and upper respiratory tract (URT) abnormalities. To identify horses with abnormal exercising ABG, and compare the proportions of horses with abnormal ABG and TW cytology, mucus or URT dysfunction with those with normal ABG results and abnormal TW cytology, mucus or URT dysfunction. Medical records of 813 horses presenting to the treadmill facility that had a complete treadmill examination, including ABG analysis, TW and URT endoscopy were selected. Diagnoses, ABG results, TW cytology and URT endoscopy were compared. Two hundred and eleven horses met the study criteria of a complete treadmill examination and could have ABG evaluated. There were no significant differences in the age distribution of horses having normal and abnormal ABG or upper respiratory tract (URT) examinations. There was a significantly higher percentage of geldings with abnormal ABG analysis. In the horses with abnormal URT examinations, there were no differences in the proportion of horses having mucus vs. no mucus. However, in the horses with normal URT, there were a higher percentage of horses with visible mucus in the group with abnormal ABG analysis. The majority of horses had abnormal TW cytology and evidence of prior EIPH, with no differences in proportions between the groups. Because such a large percentage of horses had evidence of inflammation and/or evidence of prior EIPH on TW cytology, it was not possible to determine the effect of these findings on gas exchange. Mucus was present in a larger percentage of cases with abnormal ABG analysis and normal URT examinations, suggesting that the presence of mucus may affect gas exchange. Standardbreds may be more likely to have abnormal gas exchange than Thoroughbreds. A larger number of horses is needed to determine the significance of these findings. Abnormal TW cytology and endoscopic visualised mucus may contribute to impairment of gas exchange, but they do not specifically predict abnormal ABG analysis.

Pulmonary Ultrasonographic Abnormalities Associated with Naturally Occurring Equine Influenza Virus Infection in Standardbred Racehorses

The purpose of this investigation was to determine if naturally occurring acute infectious upper respiratory disease (IRD) caused by equine influenza virus is associated with ultrasonographically detectable pleural and pulmonary abnormalities in horses. Standardbred racehorses were evaluated for signs of IRD, defined as acute coughing or mucopurulent nasal discharge. For every horse with IRD (n = 16), 1 or 2 horses with no signs of IRD and the same owner or trainer (n = 30) were included. Thoracic ultrasonography was performed within 5–10 days of the onset of clinical disease in horses with IRD. Horses without IRD were examined at the same time as the horses with IRD with which they were enrolled. The rank of the ultrasound scores of horses with IRD was compared to that of horses without IRD. Equine influenza virus was identified as the primary etiologic agent associated with IRD in this study. Mild lung consolidation and peripheral pulmonary irregularities were found in 11 (69%) of 16 of the horses with IRD and 11 (37%) of 30 of control horses. Lung consolidation (median score = 1) and peripheral irregularities scores (median score = 1) were greater in horses with IRD compared to horses without IRD (median score = 0; P < .05). Pleural effusion was not observed. Equine influenza virus infection can result in abnormalities of the equine lower respiratory tract. Despite the mild nature of IRD observed in this study, lung consolidation and peripheral pulmonary irregularities were more commonly observed in horses with clinical signs of IRD. Further work is needed to determine the clinical significance of these ultrasonographic abnormalities.

Pulmonary Ultrasonographic Abnormalities Associated with Naturally Occurring Equine Influenza Virus Infection in Standardbred Racehorses

The purpose of this investigation was to determine if naturally occurring acute infectious upper respiratory disease (IRD) caused by equine influenza virus is associated with ultrasonographically detectable pleural and pulmonary abnormalities in horses. Standardbred racehorses were evaluated for signs of IRD, defined as acute coughing or mucopurulent nasal discharge. For every horse with IRD (n = 16), 1 or 2 horses with no signs of IRD and the same owner or trainer (n = 30) were included. Thoracic ultrasonography was performed within 5-10 days of the onset of clinical disease in horses with IRD. Horses without IRD were examined at the same time as the horses with IRD with which they were enrolled. The rank of the ultrasound scores of horses with IRD was compared to that of horses without IRD. Equine influenza virus was identified as the primary etiologic agent associated with IRD in this study. Mild lung consolidation and peripheral pulmonary irregularities were found in 11 (69%) of 16 of the horses with IRD and 11 (37%) of 30 of control horses. Lung consolidation (median score = 1) and peripheral irregularities scores (median score = 1) were greater in horses with IRD compared to horses without IRD (median score = 0; P < .05). Pleural effusion was not observed. Equine influenza virus infection can result in abnormalities of the equine lower respiratory tract. Despite the mild nature of IRD observed in this study, lung consolidation and peripheral pulmonary irregularities were more commonly observed in horses with clinical signs of IRD. Further work is needed to determine the clinical significance of these ultrasonographic abnormalities.

Spectrum analysis of respiratory sounds in exercising horses with experimentally induced laryngeal hemiplegia or dorsal displacement of the soft palate.

To record respiratory sounds in exercising horses and determine whether spectrum analysis could be use to identify sounds specific for laryngeal hemiplegia (LH) and dorsal displacement of the soft palate (DDSP). 5 Standardbred horses. Respiratory sounds were recorded and pharyngeal pressure and stride frequency were measured while horses exercised at speeds corresponding to maximum heart rate, before and after induction of LH and DDSP. When airway function was normal, expiratory sounds predominated and lasted throughout exhalation. After induction of LH, expiratory sounds were unaffected; however, all horses produced inspiratory sounds characterized by 3 frequency bands centered at approximately 0.3, 1.6, and 3.8 kHz. After induction of DDSP, inspiratory sounds were unaffected, but a broad-frequency expiratory sound, characterized by rapid periodicity (rattling) was heard throughout expiration. This sound was not consistently detected in all horses. The technique used to record respiratory sounds was well tolerated by the horses, easy, and inexpensive. Spectrum analysis of respiratory sounds from exercising horses after experimental induction of LH or DDSP revealed unique sound patterns. If other conditions causing airway obstruction are also associated with unique sound patterns, spectrum analysis of respiratory sounds may prove to be useful in the diagnosis of airway abnormalities in horses.

Platelets from Thrombocytopenic Ponies Acutely Infected with Equine Infectious Anemia Virus Are Activated in Vivo and Hypofunctional

Thrombocytopenia is a consistent finding and one of the earliest hematological abnormalities in horses acutely infected with equine infectious anemia virus (EIAV), a lentivirus closely related to human immunodeficiency virus. Multifactorial mechanisms, including immune-mediated platelet destruction and impaired platelet production, are implicated in the pathogenesis of EIAV-associated thrombocytopenia. This study was undertaken to investigate whether regenerative thrombopoiesis and platelet destruction occurred in ponies acutely infected with EIAV. Circulating large, immature platelets were increased in ponies acutely infected with EIAV late in the infection when platelet count was at a nadir. Morphometric analysis of bone marrow from acutely infected ponies revealed significant increased in megakaryocyte area and megakaryocyte nuclear area. A trend toward increased numbers of megakaryocytes was also observed. Platelets from acutely infected ponies had increased surface-bound fibrinogen and ultrastructural changes consistent with in vivo platelet activation. Platelets also had hypofunctional aggregation responses to three agonists in vitro. We conclude that thrombocytopenia in ponies acutely infected with EIAV is regenerative and suggest that bone marrow platelet production is not severely compromised in these ponies. Our findings reveal that in vivo platelet activation occurs in ponies acutely infected with EIAV, and as a result platelets are hypofunctional in vitro. Activation of platelets in vivo may cause platelet degranulation or formation of platelet aggregates, which would result in removal of these damages platelets from circulation. This may represent a form of nonimmune-mediated platelet destruction in ponies acutely infected with EIAV.

Analysis of coagulation proteins as acute-phase reactants in horses with colic

Abstract Objectives To measure coagulation factor VIII:coagulant (F.VIII:C) and C1-esterase inhibitor (C1-INH), hemostasis-associated acute-phase reactant proteins, and coagulation factors VII (F.VII), IX (F.IX), and X (F.X), hemostasis proteins not associated with an acute-phase response, in a select population of horses with colic and hemostasis abnormalities, and presumed to have acute-phase changes. To compare these values and other routine hemostasis test results in the horses with colic with values for a population of healthy horses. To correlate the values of known equine acute-phase reactants, F.VIII:C and fibrinogen, to those of other tests of hemostasis. To identify hemostasis-associated acute-phase reactant proteins and gain insights into the effects the acute-phase response has on hemostatic abnormalities in horses with colic syndrome. Sample Population 54 plasma samples from horses with colic attributable to inflammatory (n = 39) or strangulating (n = 15) intestinal disorders. Procedure Plasma samples were evaluated for activities of F.VII, F.VIII:C, F.IX, F.X, C1-INH, antithrombin III, protein C, plasminogen, and α2-antiplasmin (α2AP); fibrinogen concentration; and prothrombin (PT) and activated partial thromboplastin (APTT) times. Results Horses with colic had significantly higher fibrinogen concentration, greater α2AP and protein C activities, and longer PT and APTT than did healthy horses. Horses with colic also had significantly lower mean F.VII activity than did healthy horses. Significant positive correlations between fibrinogen concentration and F.VIII:C, C1-INH, and α2AP values, and between F.VIII:C activity and fibrinogen, C1-INH, α2AP, and plasminogen values were identified. Conclusions An acute-phase response contributes to changes observed in coagulation proteins in horses with colic attributable to inflammatory and strangulating intestinal disorders. The data suggest that plasminogen, α2AP, and C1-INH should be considered equine acute-phase proteins. (Am J Vet Res 1998;59:542–545)

Haemostatic abnormalities in horses with colic--their prognostic value.

The incidence and nature of coagulation abnormalities in horses presented with colic and the possible prognostic value of these abnormalities was investigated. A coagulogram was performed on each of 24 adult Thoroughbred or Standardbred horses. A coagulogram consisted of measurements of eight parameters; platelet count, plasma fibrinogen, plasma antithrombin III (AT), partial thromboplastin time (PTT), prothrombin time (PT), thrombin clotting time (TCT), soluble fibrin monomer (SFM) and fibrin-fibrinogen degradation products (FDP). Retrospective determination of the cause of the colic and outcome (survival vs non-survival) was carried out. All patients examined had at least one abnormal parameter with the frequency being: Increased SFM 67 per cent; prolonged PTT 63 per cent; prolonged TCT 50 per cent; elevated plasma fibrinogen 46 per cent; reduced platelet count 29 per cent; reduced plasma AT 29 per cent; prolonged PT 25 per cent; and elevated serum FDP 21 per cent. When survivor and non-survivor groups were compared there was little difference in the frequency of abnormalities such as elevated SFM, elevated fibrinogen and prolonged PTT. The abnormalities which had the greatest frequency difference between non-survivors and survivors, and therefore the greatest prognostic value, were decreased AT greater than prolonged TCT = prolonged PT greater than elevated FDP greater than reduced platelet count. The frequency of these abnormalities in non-survivors compared to survivors was 8.6:1, 7.1:1, 5.7:1 and 3.6:1, respectively. The average number of abnormal parameters in non-survivors (five) was significantly greater than in survivors (two).

Recent research into the nutrition of the horse.

The majority of recent experiments in equine nutrition relates to the metabolism of protein, non-protein nitrogen, carbohydrate, calcium and phosphorus. An understanding of the significance of the nitrogen cycle is emerging in which there is a two-way movement of compounds across the wall of the G.I. tract. Some quantitative estimates of the role of microflora in this process have been made for comparison with similar processes in ruminants. However, the pathway by which the microflora contributes to the nitrogen economy and the extent to which this occurs is not established in the horse. It is well established that both glucose and volatile fatty acids are common substrates in tissue metabolism; but in contrast to evidence in the ruminant the ratio of starch to fibre in the diet does not affect the efficiency fo fibre digestibility. This, and similar observations, are explicable in terms of the anatomy of the G.I. tract of the horse. There is a scarcity of information on the secretion of digestive enzymes by the horse and on the relationship between intestinal function and certain digestive upsets. Furthermore, there is an urgent need for accurate clinical evidence for the significance of calcium and phosphorus nutrition to the development of leg abnormalities in horses. The irrelevance, for diagnosing purposes, of estimates of serum Ca and P is concluded, especially where no other relevant information is available. Haematological procedures, of diagnostic value in this respect, are available for use at least in controlled clinical conditions.