Summary Background During 2016–2018, 15 critically ill neonatal foals with acute respiratory distress associated with Chlamydia psittaci infection were presented to three referral hospitals in New South Wales. Chlamydia psittaci has not previously been associated with the development of neonatal respiratory disease. Objectives To investigate and describe the clinical features and outcome of C. psittaci infection in neonatal foals. Study design Multicentre retrospective case series. Methods The clinical, clinicopathological, necropsy and histological features of 15 foals with confirmed C. psittaci infection were reviewed and reported. Results Thirteen foals with C. psittaci infection died or were subjected to euthanasia within 36 h of hospitalisation and two foals survived to discharge. Findings during post‐mortem examination of nonsurviving foals included bronchopneumonia, pulmonary congestion, hepatic congestion and hepatic inflammation. Detection of C. psittaci was achieved using polymerase chain reaction (PCR) testing of swabs of nasal secretions (4/6) and rectal mucosa (5/7) from live foals, lung tissues of foals at necropsy (11/14) and foetal membranes (4/5). Main limitations Small numbers of confirmed cases of neonatal C. psittaci infection and inconsistent sampling methods. Conclusions Chlamydia psittaci should be considered a differential diagnosis for neonatal foals with signs of severe systemic disease, including equine neonatal acute respiratory distress syndrome (EqNARDS). Chlamydia psittaci is a zoonotic pathogen and a personal protective equipment (PPE) should be worn for the management of foals with suspected or confirmed infection.

Summary Cystic lymphangiomas are rare malformations of the lymphatics that result in the formation of a cystic mass. Where multiple cysts are seen, the condition is termed cystic lymphangiomatosis. This case describes the diagnosis and unique management of cystic lymphangiomatosis in a 10‐day‐old Thoroughbred foal. Ultrasonography, histopathology and laparoscopy were essential for diagnosis and appreciation of the extent of disease. Ultimately, the cystic lymphangiomatosis was so extensive in this foal that complete surgical excision was considered impossible and the presence of adhesions within the abdomen indicated a very poor long‐term prognosis; the owners elected for euthanasia at age 14 weeks. Although rare, lymphangioma and lymphangiomatosis should be considered as a differential diagnosis for an intra‐abdominal mass in a young horse.

This case report describes neurological signs associated with a pyogranulomatous lesion within the sacral vertebral canal of a horse. The clinical findings included urinary overflow incontinence and reduced anal, perianal and tail tone. The horse failed to respond to medical management and a guarded prognosis for return to athletic performance initiated the decision for euthanasia.

Summary This case report describes the atypical histopathological findings in a horse with anhidrosis that presented for evaluation of suspected respiratory disease during autumn/winter in a temperate climate. Anhidrosis in this horse was associated with mononuclear infiltration of T lymphocytes around sweat glands, a finding not previously reported in cases of equine anhidrosis. This report highlights the importance of considering anhidrosis as a differential diagnosis in the investigation of respiratory disease and illustrates that the condition can occur in horses residing in temperate climates.