Quarter Horse Gelding Research Articles

Grade IV gastric ulceration, pyloric aplasia, and an ectopic duodenal papilla in a 13-year-old Quarter Horse gelding evaluated for recurrent colic.

The objective of this Case Report was to describe the clinical manifestation and postmortem findings of a horse evaluated for recurrent colic diagnosed with pyloric aplasia and an ectopic duodenal papilla. 13-year-old Quarter Horse gelding. The horse was presented to a referral center for signs of colic that were unresponsive to management on the farm. No abnormalities were noted on rectal palpation; however, upon passage of a nasogastric tube, 31 L of net gastric reflux was obtained. Gastroscopy noted grade IV squamous ulceration and moderate glandular ulceration, severe gastric dilatation, an abnormally positioned gastric outflow tract, and an ectopic duodenal papilla leaking bile-like fluid directly into the stomach. The horse was initially treated with gastroprotectants, promotility agents, and dietary modifications. Following treatment failure and repeated episodes of colic with increasing severity, the horse was euthanized and a necropsy performed. At necropsy, it was confirmed that the aboral aspect of the stomach formed a dilated pouch and continued directly into the proximal duodenum with no discernible pyloric sphincter. The area of the pylorus was delineated by a faint indentation. The ectopic duodenal papilla was traced to the liver. Congenital gastric abnormalities, even in adult horses, should be considered as differential diagnoses when investigating horses presenting with a history of chronic colic. Neither pyloric aplasia nor an ectopic duodenal papilla have been described in the equine literature, and this Case Report raises awareness of the presence of such malformations and their manifestations.

Successful management of pneumonia and pyogranulomatous cranial mediastinitis due to Coccidioides species infection with fluconazole in a 3‐year‐old horse

SummaryA 3‐year‐old Quarter Horse gelding originating from Texas presented for fever and inappetence. An encapsulated, mixed echogenic cranial mediastinal mass visible ultrasonographically in the left and right fourth intercostal space that displaced the heart caudally was identified. Histological evaluation of needle biopsies obtained under general anaesthesia revealed a severe pyogranulomatous inflammatory process associated with intralesional round, 15–25 μm in diameter, thick double‐contoured cell wall fungal structures. Sequencing of products obtained from DNA extracted from the paraffin‐embedded biopsy sample and a panfungal PCR assay targeting the large ribosomal unit region had a 99.1% identity to either Coccidioides immitis or C. posadessii. Bronchoscopy revealed purulent exudate in the right primary bronchus. Cytological evaluation of bronchial alveolar lavage fluid (BALF) contained 96% moderately degenerative neutrophils and 4% macrophages. Fungal structures were not appreciated in the BALF. However, the mediastinitis could have resulted from inhalation and dissemination of arthroconidia through lymphatics or directly from the lung parenchyma. Quantitative immunodiffusion of serum for the presence of coccidioidal IgG antibodies yielded a titre of 1:256 suggestive of disseminated coccidioidomycosis. After oral fluconazole for 24 months, the horse's general health and athletic performance had returned to normal and the mediastinal mass was not appreciated sonographically.

Musculoskeletal examination of the forelimb of the horse.

The intention of this tutorial video is to illustrate the methods of examining the forelimb and neck of a horse in order to identify abnormalities that may be associated with lameness or disease. A 16-year-old quarter horse gelding was used for examination. The horse was examined for abnormalities by means of physical examination. The examination of the forelimb and neck of the horse was successfully completed. This examination technique is required to identify abnormalities in the equine forelimb and can be utilized during a lameness examination.

Lymphocytic myenteric ganglionitis associated with equine herpesvirus infection: A cause of chronic intestinal pseudo‐obstruction and recurrent colic in an adult horse

SummaryThis report describes a rare case of chronic intestinal pseudo‐obstruction (CIPO) in a 12‐year‐old Quarter Horse gelding, caused by lymphocytic myenteric ganglionitis (MG) associated with equine herpesvirus 1 (EHV‐1) and equine herpesvirus 5 (EHV‐5) infection. The horse presented with recurrent colic and weight loss over 1.5 years. Repetitive transrectal examinations consistently revealed small colon impaction and enlargement. During postmortem examination alternating segments of enlarged and reduced luminal diameter were observed throughout the entire intestinal tract. MG with lymphocytic infiltrates and neuronal degeneration of the large intestine were found on histopathological analysis. Additionally, polymerase chain reaction (PCR) analysis confirmed the presence of EHV‐1 and EHV‐5 DNA in affected intestinal tissues. Further research is needed to understand the pathophysiology of MG and its association with herpesviruses. Early recognition and diagnosis of MG‐associated CIPO may improve treatment approaches and outcomes for future cases.

Surgical treatment of cervical (C7‐T1) instability caused by discospondylitis in a horse

SummaryDiscospondylitis is an inflammatory condition involving the vertebral bodies and is rarely reported in horses. Clinical signs are associated with neck stiffness and forelimb ataxia. In other species, treatment consists mainly of antibiotics coupled with non‐steroidal analgesics for a period of 3–12 weeks. An inadequate response to conservative treatment requires surgical intervention, but there is limited information in the literature regarding surgical management in large animals. A 3‐year‐old Quarter Horse gelding presented for an approximately 4‐week history of generalised stiffness and reluctance to move. Computed tomography with myelogram revealed abnormalities consistent with discospondylitis at the level of the seventh cervical and first thoracic vertebrae (C7‐T1). The patient underwent cervical vertebral interbody fusion using a combination of compression of the vertebral bodies using cortical screws in lag fashion and a 4‐hole locking compression plate (LCP). The patient was discharged from the hospital with marked improvement. At the time of this report, 4 months after the procedure, the horse continues to show marked improvement in mobility and range of motion.

Discovery and comparative genomic analysis of a novel equine anellovirus, representing the first complete Mutorquevirus genome

The complete genome of a novel torque teno virus species (Torque teno equus virus 2 (TTEqV2) isolate Alberta/2018) was obtained by high-throughput sequencing (HTS) of nucleic acid extracted from the lung and liver tissue of a Quarter Horse gelding that died of nonsuppurative encephalitis in Alberta, Canada. The 2805 nucleotide circular genome is the first complete genome from the Mutorquevirus genus and has been approved as a new species by the International Committee on Taxonomy of Viruses. The genome contains several characteristic features of torque teno virus (TTV) genomes, including an ORF1 encoding a putative 631 aa capsid protein with an arginine-rich N-terminus, several rolling circle replication associated amino acid motifs, and a downstream polyadenylation signal. A smaller overlapping ORF2 encodes a protein with an amino acid motif (WX7HX3CXCX5H) which, in general, is highly conserved in TTVs and anelloviruses. The UTR contains two GC-rich tracts, two highly conserved 15 nucleotide sequences, and what appears to be an atypical TATA-box sequence also observed in two other TTV genera. Codon usage analysis of TTEqV2 and 11 other selected anelloviruses from five host species revealed a bias toward adenine ending (A3) codons in the anelloviruses, while in contrast, A3 codons were observed at a low frequency in horse and the four other associated host species examined. Phylogenetic analysis of TTV ORF1 sequences available to date shows TTEqV2 clusters with the only other currently reported member of the Mutorquevirus genus, Torque teno equus virus 1 (TTEqV1, KR902501). Genome-wide pairwise alignment of TTEqV2 and TTEqV1 shows the absence of several highly conserved TTV features within the UTR of TTEqV1, suggesting it is incomplete and TTEqV2 is the first complete genome within the genus Mutorquevirus.

Chronic weight loss, intermittent hematuria, polyuria, and polydipsia in a 23-year-old Quarter Horse gelding.

Chronic weight loss, intermittent hematuria, polyuria, and polydipsia in a 23-year-old Quarter Horse gelding.

Spontaneous bilateral superficial digital flexor tendon rupture in a horse with guttural pouch empyema and suspected purpura hemorrhagica

SummaryCase historyAn 11‐year‐old Quarter Horse gelding was evaluated for urticaria, generalised discomfort, distal limb oedema, spontaneous dropped fetlocks, and progressive hindlimb lameness. Prior infection status with Streptococcus equi subspecies equi was unknown.Clinical findingsThe horse had bilateral hindlimb oedema, generalised wheals, progressive hindlimb lameness, and dropped fetlocks of the right and left hindlimbs. The horse was intermittently pyrexic and was ultimately subjected to euthanasia due to deteriorating clinical status.DiagnosisSuspected purpura hemorrhagica associated with leukocytoclastic vasculitis of the superficial digital flexor tendons and spontaneous tendon rupture.Treatment and outcomeThe horse was treated with a combination of antibiotic therapy (enrofloxacin and penicillin), nonsteroidal anti‐inflammatory drugs (phenylbutazone) and corticosteroids (dexamethasone), with no improvement in clinical status. The horse was subjected to euthanasia due to poor prognosis and unfavourable response to therapy. Post‐mortem examination revealed unilateral guttural pouch empyema, multifocal cutaneous infarction and bilateral rupture of the superficial digital flexor tendons. Streptococcus equi subspecies equi was isolated in pure culture from the guttural pouch. Microscopically, leukocytoclastic vasculitis typical of purpura hemorrhagica was documented in the skin. Unexpectedly, similar vasculitis was also observed in the superficial digital flexor tendons.Clinical relevanceThis report documents the first equine case of suspected purpura hemorrhagica associated with leukocytoclastic vasculitis of the superficial digital flexor tendons and spontaneous tendon rupture. Spontaneous tendon rupture should be considered a potential sequela to infection with Streptococcus equi subspecies equi in horses due to immune‐mediated vasculitis.

Standing jejunal enterotomy for resolution of an ileal impaction

SummaryA 22‐year‐old American Quarter Horse gelding was referred to the JT Vaughan Large Animal Teaching Hospital at Auburn University, College of Veterinary Medicine for moderate signs of abdominal pain responsive to sedation. A presumptive preoperative diagnosis of ileal impaction was made based on physical examination, ultrasonography of the abdomen and clinical pathological data. Despite appropriate medical therapy and improvement in the diagnostic and clinical parameters, the gelding continued to be uncomfortable. A standing right flank laparotomy facilitated access to the ileum which contained approximately 80 cm of consolidated ingesta from the ileocaecal orifice extending orally. The distal jejunum was exteriorised and an enterotomy performed, permitting lavage of the ingesta and resolution of the impaction. The gelding was discharged 6 days after surgery. Two weeks after surgery, the gelding re‐presented for surgical treatment of an incisional abscess. At 4‐month follow‐up, the gelding was reportedly doing well. The described surgical technique may be a viable option for resolution of ileal impactions in horses non‐responsive to medical management when exploratory celiotomy under general anaesthesia is not possible due to financial constraints, the health of the horse or other reason.

Acute hindlimb paresis caused by extension of a peripheral nerve sheath tumour into the spinal canal of a horse

SummaryA 10‐year‐old Quarter Horse gelding presented for a large, slowly growing mass in the right thoracic region caudal to the withers (approximately at the level of thoracic vertebrae 10 to 16). The mass was surgically removed, the horse returned to normal riding activity, and no external regrowth was observed. Two years after surgery, the horse developed progressive signs of hindlimb weakness, ataxia and adopting a dog‐sitting stance. Post‐mortem examination confirmed spinal canal infiltration and spinal cord compression (at the level of the 12th thoracic vertebra) by a similar soft tissue sarcoma as diagnosed previously. Immunohistochemistry confirmed the tumour as a peripheral nerve sheath tumour (PNST) likely originating from the twelfth thoracic spinal nerve. This report demonstrates that with incomplete tumour resection, local recurrence and extension of a PNST into the central nervous system can occur even years after initial tumour removal. Immunohistochemistry to differentiate the type of soft tissue sarcoma in cases with close association to the nervous system may prove beneficial to anticipate this uncommon complication. Early surgical resection with adjunctive therapies should be considered in these cases.

Use of serial standing computed tomography for diagnosis, treatment and monitoring of a horse with acute myonecrosis of the head

SummaryAn 11‐year‐old American Quarter Horse gelding was referred to the JT Vaughan Large Animal Teaching Hospital at Auburn University, College of Veterinary Medicine, for investigation of acute and severe right‐sided facial swelling and nasal discharge. Standing computed tomographic (CT) examination of the head identified severe soft tissue swelling surrounding the right mandible, emphysema within the soft tissues tracking along fascial planes and right‐sided caudal and rostral maxillary sinusitis. Using CT identification and ultrasound guidance, several targeted fasciotomies were created into the right masseter, cranial cervical musculature, supraorbital space and caudo‐medial aspect of the mandible. The right‐sided sinusitis was treated by right conchofrontal sinus trephination and lavage. Aerobic and anaerobic cultures obtained from the fasciotomy sites and conchofrontal sinus both yielded Prevotella intermedia and Peptostreptococcus asaccharolyticus. During hospitalisation, serial, standing CT examinations were performed for monitoring case progression and guiding further fasciotomies in the face of continued myonecrosis. Follow‐up CT performed at 1 month showed resolution of the emphysema and presence of chronic right ventral conchal sinusitis. The sinusitis was treated by fenestration of the right ventral concha with a diode laser via the nasal passage.

Pathology in Practice.

HistoryA 16-year-old 487.2-kg (1,071.8-lb) Quarter Horse gelding was presented to a veterinary medical teaching hospital because of a 4- to 5-month history of intermittent, unilateral (right-sided) nasal discharge and epistaxis that did not improve with antimicrobial treatment. Additionally, right facial crest swelling had been observed approximately 3 weeks prior to presentation. The referring veterinarian performed skull radiography, which revealed a large mass lesion in the horse's right nasal cavity.Clinical and Gross FindingsOn physical examination, there was mildly decreased airflow from the right nostril, mildly increased expiratory noise on tracheal auscultation, and a small firm nodule over the

Standing biceps brachii tenectomy to treat chronic bicipital tendinopathy associated with bursal fibrosis and humeral adhesions in a Quarter Horse gelding

SummaryChronic biceps brachii (BB) tendinopathy is a rare cause of lameness in horses that can be challenging to diagnose and treat successfully. This pathology is typically insidious in onset and unresponsive to conservative treatment. A 12‐year‐old Quarter Horse gelding presented for chronic severe lameness of the left forelimb that was localised to the left shoulder area. The horse was unresponsive to conservative management and surgical exploration revealed a grossly enlarged proximal BB tendon, a thickened fibrotic bicipital bursa and adhesions between the tendon, humerus and bursa. With standing sedation and local anaesthesia, the adhesions were debrided and 10 cm of the affected tendon was excised. Immediately post‐operatively, the left forelimb lameness dramatically decreased. The horse recovered well and after rehabilitation returned to the previous level of athletic performance without evidence of lameness or gait abnormality. In this case, tenectomy of the chronic unresponsive BB tendinopathy, with associated bursal fibrosis and humeral adhesions, was successful and resulted in a return to previous athletic performance without complications. Standing excision of the BB tendon may be a viable treatment option for chronic BB tendinopathy and associated conditions when there is significant compromise to the integrity of the BB tendon.

Actinomyces as a Cause of Osteomyelitis of the Nasofrontal Suture in a Gelding

A 7-year-old American Quarter Horse gelding was referred to the JT Vaughan Large Animal Teaching Hospital at Auburn University, College of Veterinary Medicine, for an investigation of a recurrent swelling of the nasofrontal region. Computed tomography examination of the skull was most consistent with a sequestrum of the left nasofrontal suture with associated focal osteomyelitis and left conchofrontal sinusitis. Surgery to remove the sequestrum, debride the devitalized bone, and flush the left conchofrontal sinus was performed. A microbial culture was obtained at the time of surgery, which yielded a mixed heavy growth of an Actinomyces species. Quantitative PCR indicated a species with 93% resemblance to Actinomyces funkei. A treatment course of two weeks of oral chloramphenicol was prescribed. At three-month follow-up, the owner reported resolution of the swelling.

Bicavitary effusion in a horse with multicentric lymphoma

SummaryA 14‐year‐old Quarter Horse gelding presented for a 2‐week history of increased respiratory rate, fever and weight loss. The referring veterinarian performed an ultrasonographic examination on the farm and considered a differential diagnosis of pleuritis and pleuropneumonia. On presentation, transtracheal wash showed suppurative septic inflammation with bacteria within macrophages. Thoracic ultrasonography showed increased hypoechoic fluid in the pleural and peritoneal cavities. Cytologic analysis of pleural and peritoneal fluids revealed lymphorrhagic effusion with atypical lymphocytes, suggestive of a lymphatic flow obstruction or lymphoma. Treatment consisted of drainage of the pleural fluid, anti‐inflammatory agents, fluid therapy and antimicrobial therapy. Continued fluid accumulation in the thoracic cavity, tachypnoea, lack of response to pain medication and progressive lethargy resulted in the horse being subjected to euthanasia. At necropsy, bicavitary effusion was confirmed and histopathological diagnosis of multicentric lymphoma was made. Horses presenting with pleural effusion should also be evaluated for peritoneal effusion, as bicavitary effusion may indicate noninflammatory conditions such as neoplasia.

Upper respiratory signs associated with Anaplasma phagocytophilum infection in two horses

SummaryAn adult Quarter Horse gelding (Case 1) was evaluated for tachypnoea and acute dysphagia. A 20‐year‐old Quarter Horse gelding (Case 2) was evaluated for respiratory stertor and severe, acute swelling of the head in the submandibular region. A physical examination, complete blood count, blood chemistry, upper airway endoscopy, and peripheral blood Anaplasma phagocytophilum polymerase chain reaction were completed for both horses. Both horses tested positive for A. phagocytophilum. The upper airway endoscopy for Case 1 revealed a feed contaminated pharynx, absent swallowing reflex, and left laryngeal hemiplagia. The upper airway endoscopy for Case 2 revealed severe diffuse pharyngeal swelling occluding the airway. Due to increased respiratory effort in Case 2, a tracheotomy was performed. In both horses, treatment consisted of intravenous oxytetracycline 6.6 mg/kg bwt i.v. q. 24 h for 2–3 days followed by minocycline 4 mg/kg bwt per os q. 12 h for 10–14 days. Both horses made full recoveries.

Tenoscopic removal of a protruding osteophyte as a treatment for chronic common digital extensor tendinopathy and associated tenosynovitis

SummaryThis report describes an adult Quarter Horse gelding that was presented for evaluation of chronic tenosynovitis of the right common digital extensor tendon sheath. Radiographic and tenoscopic evaluation confirmed the presence of a periarticular osteophyte from the third metacarpal bone protruding into the common digital extensor tendon sheath. Tenoscopic surgical resection of the osteophyte and debridement of the affected tendon resolved the tenosynovitis and associated right forelimb lameness. Osteophytes in this location can be a source of focal traumatic tendonitis of the common digital extensor tendon which can lead to a chronic tenosynovitis of the common digital extensor tendon sheath. Tenoscopic debridement and lavage is a viable treatment option for chronic nonseptic common digital extensor tendinopathy and associated tenosynovitis.

Ossifying fibroma as a cause of blindness in a 5‐year‐old Quarter Horse gelding

SummaryA 5‐year‐old Quarter Horse gelding presented to Texas A&M University Veterinary Medical Teaching Hospital with a several week history of bilateral blindness. Neurological deficits included an absent menace response and severe atrophy of the optic nerve head in the left eye (OS) as well as decreased vision in the right eye (OD). Advanced imaging consisting of computed tomography (CT) and magnetic resonance imaging (MRI) confirmed a large mass in the base of the skull invading the sinuses and asymmetrically compressing the optic nerves rostral to the optic chiasm. Due to the size and location of the mass as well as severity of associated neurological signs, humane euthanasia was elected. Necropsy examination identified a large mass effacing the sphenopalatine sinuses and compressing the optic nerves. Histologically, the mass was identified as an ossifying fibroma (OF) and degeneration of the optic nerves was confirmed. As an OF in this location has never been described in a horse, this case demonstrates a new differential for blindness in horses.

Small intestinal adenomatous polyps resulting in chronic obstruction in a 3‐year‐old Quarter Horse gelding

SummaryA 3‐year‐old, Quarter Horse gelding was admitted to Kansas State University Veterinary Health Center with a primary complaint of colic. The horse had a 3‐month history of recurrent colic and progressive weight loss. On physical examination, the horse was quiet, alert and responsive. The horse's mucous membranes were pink and capillary refill time was 2 s. His rectal temperature was 37.6°C (99.6°F), heart rate was 56 beats/min and respiration rate was 16 breaths/min. Rectal palpation revealed an approximately 5 cm dilated, firm, tubular, mass traversing from left caudal abdomen to mid abdomen. Nasogastric intubation obtained 6 L net reflux. A 5 cm diameter small intestinal intraluminal mass was detected by abdominal ultrasound. Complete blood count, serum chemistry and peritoneal fluid analysis were performed and all results were unremarkable. The horse was humanely euthanised due to pain and financial constraints. Post‐mortem examination and histopathology revealed a 15 × 5 × 5 cm polyp with multiple smaller satellite polyps that obstructed the distal duodenum. Colic was considered secondary to small intestinal obstruction and luminal distension caused by the adenomatous polyps. To the authors’ knowledge, this is the first report to include ultrasound images of a small intestine adenomatous polyp that caused small intestinal obstruction and colic in a 3‐year‐old horse.

Use of magnetic resonance imaging in the diagnosis of a tibial fissure fracture in a four-year-old American Quarter Horse gelding: A clinical case

The summary describes a clinical case of a four-year-old American Quarter Horse gelding presented for evaluation of a grade 2-3 (2-3/5) lameness of the right hind limb. The patient underwent a thorough clinical and orthopaedic examination including limb flexion tests and diagnostic anaesthesia. Intra-articular anaesthesia of the stifle joint was impossible because of the uncooperative behaviour of the horse. However, provocation tests and radiographs proved diagnostically inconclusive. Therefore, magnetic resonance imaging of the right stifle was performed, revealing a tibial fissure fracture. The result was diagnostic and surprising, considering the degree and chronic nature of the lameness. Based on the findings of magnetic resonance imaging, the horse underwent surgery by the locking compression technique to restore full limb function. All implants were removed six months after surgery. The gelding returned to training without any signs of lameness..