Osteopetrosis in a neonatal donkey

Osteopetrosis is a rare disorder characterised by a defect in osteoclastic bone resorption. This report describes osteopetrosis in a neonatal donkey that suffered a displaced tibial fracture. Radiographic examination identified generalised reduction in medullary cavity size, thickened mid‐diaphyseal cortices and conical metaphyseal bone extending toward the mid‐diaphysis of long bones. Postmortem examination identified additional fractures and brittle bones. Histologically, osteoclasts were absent in multiple bone sections. Diaphyseal cortices consisted of concentric bone lamellae with marrow tissue infiltration. Large wedges of secondary spongiosa extended from the metaphyseal growth plate. Clinical and histopathological features were similar to an osteoclast‐deficient, autosomal recessive form of osteopetrosis in humans.     

Adrenocortical carcinoma in a donkey

An adrenocortical carcinoma was found in an eight-year-old male donkey. The main clinical feature was severe depression and inappetence. The animal died 24 hours after hospitalization. Necropsy revealed a large tumor around the anterior pole of the left kidney and metastases to liver, heart and lung. Fibrous adhesions were seen between the tumor and the intestinal serosa. The abdominal cavity contained a large amount of red-brown fluid.     

Besnoitiosis in a miniature donkey

A 1-year-old male miniature donkey ( Equus asinus ) from a herd of eight was presented with a 9-month history of pruritic dermatitis, lethargy and anorexia. Physical examination revealed diffuse lichenification and scales involving the skin of the face, head and dorsum from the neck to the pelvis. The main histological alteration within the superficial and deep dermis was the presence of multiple large, spherical, thick walled, protozoal Besnoitia cysts. In addition, the inflammatory response consisted of a moderate, superficial and deep perivascular, mixed mononuclear cell infiltrate, with epidermal hyperplasia and compact orthokeratosis. Based upon the large size of the protozoal cysts and the ultrastructural features of the bradyzoites contained therein (conoid, polar ring, rhoptries, micronemes and microtubules), a diagnosis of cutaneous besnoitiosis was established. Treatment with trimethoprim-sulphamethoxazole resulted in significant clinical improvement. To our knowledge, this is the first reported case of besnoitiosis in a miniature donkey in North America.     

Bilateral Morgagni hernia in a donkey

This case report describes the clinical presentation and management of a donkey admitted with acute signs of abdominal pain that was diagnosed with a bilateral Morgagni hernia, a rare type of congenital diaphragmatic hernia. For more than 8 months before presentation, the donkey had been showing signs of recurrent mild abdominal pain that responded favourably to medical treatment. On admission, the donkey had mild tachycardia and tachypnoea. Radiography and ultrasound of the thorax and abdomen showed thoracic herniation of the large colon. Exploratory laparotomy was performed, and the sternal and diaphragmatic flexures of the large colon, as well as the left hepatic lobe, were found incarcerated in a bilateral Morgagni hernia. Intestine and liver were removed from the hernia, and the large colon was exteriorised. The defect in the diaphragm was repaired by stapling a polyester mesh circumferentially around the hernia ring and covering the mesh with an excised section of the greater omentum. No further complications and no recurrence of colic were observed during an 8-month follow-up period.     

Rectal atresia in a newborn donkey

A case of a type I rectal atresia (also known as membranous rectal atresia) in a newborn donkey is reported. Clinical examination, survey radiographs and barium enema radiographs suggested rectal atresia. An exploratory laparotomy was performed; however, surgical correction of the defect was not possible due to the narrow pelvic cavity. Euthanasia was performed. At necropsy, it was possible to observe a fibrous cord connecting the small colon to a residual rectal ampulla, which opened to a normal anus. The radiographic and anatomical characteristics enabled the classification of the defect as type I rectal atresia, which is a rare congenital anomaly that is difficult to correct through surgery. This report contributes to the study of rectal atresia in newborn equids, alerts for the occurrence in donkeys and is, to our knowledge, the first to be reported in this species in Brazil.     

Tracheal obstructions in two horses and a donkey

The clinical signs associated with intramural tracheal obstructions in two horses and a donkey were respiratory distress and coughing, which were aggravated by exercise and excitement. The obstructions were at the level of the thoracic inlet and consisted either of flattening of the cartilage rings in the dorsoventral plane or of cartilage rings having a scroll-like conformation. They appeared to be developmental in origin and to have been present for a considerable time before the onset of clinical signs. Endoscopy and radiography were helpful in the diagnosis of the condition.     

Osteosarcoma of the proximal radius in a donkey

A mature donkey was presented for evaluation of a forelimb lameness and presence of a large mass on the left forelimb distal to the elbow joint. Clinical examination, radiographs and cytological examination of ultrasound‐guided fine needle aspirates of the mass led to a presumptive diagnosis of osteosarcoma. The donkey was subsequently subjected to euthanasia. Post mortem examination confirmed the diagnosis of osteosarcoma in the proximal radius with expansion of the mass through the ulnar cortex and metastases to liver and regional lymph nodes, areas of metastasis previously unreported in the equine literature.