Toxoplasmosis in a calf.

Gross post mortem and histopathological changes are described in a calf with toxoplasmosis. The major pathological changes were restricted to the lungs and kidneys and comprised interstitial pneumonia with multifocal necrosis, and glomerular necrosis. Many pseudocysts were present in both organs. The calf had been in close contact with young cats, one of which was killed and examined and shown to have a high antibody titre to Toxoplasma gondii, although there was little histological evidence of infection. No antibodies to toxoplasma were detected in serum from the dam of the calf, and accordingly, it is suggested that the cat was the source of infection for the calf.     

Nasal nocardiosis in a calf.

Nasal nocardiosis was found in a female Japanese Black calf, 11 months of age. Macroscopically, the posterior half of the left nasal passage was completely obstructed by yellowish brown caseous substance and the mucosa was irregularly thickened. In the brain, a few soft brown foci were present in the olfactory bulb and frontal lobe. Microscopically, there were closely packed granulomas in the nasal cavity and brain. The lesions were characterized by a center of cellular debris surrounded by epithelioid macrophages, neutrophils, lymphocytes and multinucleated giant cells of the Langhans type. Special stains revealed the presence of a large number of filamentous branching gram-positive, partially acid-fast organisms in these epithelioid cells and giant cells, and in cellular debris.     

Cerebral babesiosis in a new-born calf.

A case of intra-uterine transmission of Babesia bovis is reported. The calf was born normally but showed signs of intravascular haemolysis and nervous involvement 24 h after birth. It died shortly afterwards from cerebral babesiosis. The dam was not clinically affected.     

Brachyspina syndrome in a Holstein calf.

A stillborn premature Holstein calf was necropsied. The calf had severely reduced body weight and shortening of the vertebral column. The limbs appeared long and thin. Radiography and computer tomography scanning were performed, demonstrating malformation of the vertebral column. In addition, malformation of the kidneys, testicles, and heart was found at necropsy. Histologically, absence or incomplete development of intervertebral discs and complete or partial fusion of the epiphyses of adjacent vertebrae were found. In some areas, diaphyses of adjacent vertebrae were fused due to absence of epiphyses and intervertebral discs. Disturbed ossification of epiphyses in the appendicular skeleton was also present. The etiology of this syndrome was not identified. An inherited cause is possible due to a close relationship between the parents.     

Aortic valvular dysplasia in a calf.

Aortic valvular dysplasia, a congenital abnormality not previously reported in cattle, was diagnosed in a calf with a pulsating mass at the base of its neck, an enlarged area of cardiac dullness and a loud (grade IV/V) systolic cardiac murmur. Electrocardiography and thoracic radiography demonstrated that the left atrium and ventricle were enlarged. Dysplasia of two aortic valve cusps and post stenotic dilatation of the ascending aorta were identified by echocardiography and confirmed post mortem.     

Fibrocartilaginous embolic myelopathy in a calf.

A 5-month-old Angus heifer with a history of acute hindlimb paresis that quickly progressed to lateral recumbency was necropsied. Gross lesions included a 6-cm segment of gray to brown discoloration and softening of the right ventrolateral spinal cord between T2 and T3. Microscopically, there was liquefactive necrosis of ventrolateral white and gray matter, and multiple intravascular emboli partially or completely occluded many intralesional and adjacent spinal and meningeal arteries and veins. Emboli were alcian blue positive, consistent with fibrocartilage of the nucleus pulposus of the intervertebral disk. No gross abnormalities were detected in the vertebrae or intervertebral disks. Fibrocartilaginous embolic myelopathy appears to be very rare in cattle; however, it should be considered in cases of acute, nonprogressive spinal cord dysfunction.     

Generalized tuberculosis in a 45 day-old calf.

The objectives of the present study were to describe pathomorphological and immunohistochemical features of generalized natural tuberculosis in a 45 day-old female calf. The characteristic lesion of tuberculosis was productive type which was located in the lung, liver, and especially in the lymph nodes (mediastinal, bronchial, mesenterial, portal, prescapular, renal and caudal sternal lymph nodes). Mycobacterium bovis antigens were seen generally in the cytoplasma and around the macrophages, rarely in necrotic areas and Langhans giant cells by avidin-biotin complex peroxidase method.     

Naturally occurring Tyzzer's disease in a calf.

Naturally occurring Clostridium piliforme infection (Tyzzer's disease) was found in a calf. Light microscopic examination revealed multifocal coagulative necrosis in the liver, catarrhal gastroenteritis, tracheitis and pneumonia, and thymic atrophy. Warthin-Starry staining clearly showed large filamentous bacilli in bundles or criss-cross patterns within the hepatocytes and epithelium and smooth muscle cells of the ileum and cecum. Immunohistochemistry using anti-C. piliforme RT and MSK strain antisera showed positive reaction against the bacilli. Electron microscopic examination revealed bacilli within the hepatocytes that demonstrated a characteristic vegetative form, with peritrichous flagella, and spores. The polymerase chain reaction (PCR) study using the paraffin-embedded liver sections, the 196-bp DNA fragment specific to 16S ribosomal RNA of C. piliforme was amplified. The characteristics of these bacilli are consistent with those of of C. piliforme. The PCR technique using paraffin-embedded sections should be useful for confirming C. piliforme infection in spontaneous cases.