N. Pusterla

Echocardiography of the normal bovine heart: technique and ultrasonographic appearance

Fifty-one clinically healthy cows were examined ultrasonographically from the third and fourth intercostal spaces on both sides of the thorax. A 3.0 MHz transducer was used and the heart was examined in the caudal long, caudal short and cranial long axes on the right side, and in the caudal and cranial long axes on the left side. In each position the optimal transducer orientation and the images of the structures were recorded. In the caudal long axis view of the heart on the right (transducer positioned at the fourth intercostal space), all four chambers were visible with the transducer positioned 8 to 10 cm dorsal to the level of the olecranon. The left ventricular outflow tract, consisting of the aortic valve and ascending aorta, were visible in the same position with the transducer rotated 10 to 400 clockwise. In the caudal short axis view of the heart on the right, the left and right ventricles were visible in cross-section with the transducer held at right angles to the ribs in the fourth intercostal space, 3 to 6 cm dorsal to the olecranon and tipped slightly dorsally. In the cranial long axis view of the heart on the right, the right ventricular outflow tract, consisting of the pulmonary valve and pulmonary artery, was visible in the third intercostal space, 8 to 10 cm dorsal to the olecranon with the transducer angled craniodorsally and rotated 10 to 20° clockwise. In the caudal long axis view of the heart on the left, the left and right ventricles and the left ventricular outflow tract were visible with the transducer placed in the fourth intercostal space. In the cranial long axis view on the left, the right ventricular outflow tract was visible.

Experimental cross-infections with Ehrlichia phagocytophila and human granulocytic ehrlichia-like agent in cows and horses

Four cows and four horses were infected experimentally with Ehrlichia phagocytophila, the cause of tickborne fever in ruminants, and with human granulocytic ehrlichia-like agent, a recently discovered species that infects people, horses and dogs in the USA and Europe. They were infected in either order, 30 days apart, to investigate serological cross-reactivity within the E phagocytophila genogroup. The course of infection was assessed by routine clinical, haematological, serological and polymerase chain reaction (PcR) examinations. Two of the cows infected with E phagocytophila and two of the horses infected with granulocytic ehrlichia-like agent, developed characteristic signs of ehrlichiosis. When the same animals were infected with their heterologous ehrlichial isolate 30 days later, they did not develop clinical signs of disease. The infection of the other two cows with human granulocytic ehrlichia-like agent and the other two horses with E phagocytophila, resulted in asymptomatic seroconversion. When the same animals were infected with their homologous ehrlichial isolate 30 days later, they remained asymptomatic and had normal haematological results and negative PCRS until the end of the monitoring period, 60 days after the first infection. In these animals, there was an increase in antibody titre after the second infection which was interpreted as a specific immune response, and as a reactivation of the immune response to the first infection.

ULTRASONOGRAPHIC FINDINGS IN COWS WITH LEFT DISPLACEMENT OF THE ABOMASUM

Forty-eight cows with left displacement of the abomasum (LDA) and three clinically healthy control cows were examined ultrasonographically from the 11th and 12th intercostal spaces on the left side. In the controls, the rumen was immediately adjacent to the left abdominal wall, whereas in the cows with LDA the rumen was generally immediately adjacent to the left abdominal wall ventrally, but displaced by the abomasum more dorsally. The ultrasonographic findings were generally consistent in the cows with LDA. The ingesta that were visualised ventrally in the abomasum appeared echogenic to hypoechogenic and, in a few cows, the abomasal folds were visible as elongated, echogenic, sickle-shaped structures. The dorsal abomasal gas cap was characterised by reverberation artifacts from the abomasal surface.

Ultrasonographic findings in cattle with pleuropneumonia

The clinical, ultrasonographic and radiographic findings in three cows and one bull with pleuropneumonia are described. All the animals had fever, indigestion, tachypnoea and abnormal lung sounds. Percussion of the thoracic wall elicited signs of pain and tests for foreign bodies were positive. Ultrasonographic examination revealed an accumulation of anechogenic to hypoechogenic fluid in the pleural space in the ventral thorax of all the animals. In one animal, echogenic bands of fibrin were observed between the thoracic wail and pulmonary surface. In another, parts of the right lung were not inflated because of severe bronchopneumonia. Radiographic examination revealed a pleural effusion, apparent as a horizontal fluid line, in three animals. In addition, the increased radiopacity in parts of the dorsal lung fields and increased bronchial and peribronchial markings suggested bronchopneumonia. In three animals, the radiographs revealed linear foreign bodies in the reticulum, suggesting that the pleuropneumonia was caused by the penetration of the foreign body into the thoracic cavity. A diagnosis of pleuropneumonia was made in all the animals on the basis of the clinical, ultrasonographic and radiographic findings and the analysis of the pleural fluid. The diagnosis was confirmed at slaughter in three of them; the fourth animal was treated and was clinically healthy when it was discharged.

Experimental infection of four horses with Ehrlichia phagocytophila

Four clinically healthy horses which were negative for antibodies to Ehrlichia phagocytophila, the agent of bovine ehrlichiosis, were infected experimentally with E phagocytophila-containing bovine leucocytes, administered intravenously. The horses were examined daily for four weeks, and blood samples were collected daily for cytological, haematological and biochemical examination and for a nested polymerase chain reaction (PCR). An indirect immunofluorescence test was used to determine when the horses seroconverted and the duration of positive titres. There were no abnormal clinical, haematological or biochemical findings in any of the four horses and all the PCRS yielded negative results. However, all the horses seroconverted with reciprocal titres of up to 1280, and the positive titres persisted for up to five months.

Elaphostrongylus cervi infection in a Swiss goat

ter were less fertile (Tebble and others 2001). It was disappointing that the presence of a corpus luteum was not considered useful. If a corpus luteum is present, the cyst is not endocrinologically active and the standard treatment to remove the corpus luteum should be given, that is, prostaglandin. Cyst internal diameter and wall thickness were considered useful as aids to differentiate follicular and luteal cases. This concurs with the observation that cyst wall thickness is positively correlated with plasma progesterone concentration and success of treatment with prostaglandin (Ribadu and others 1994, Scott and Dobson 1997). This study has assessed current methods for cyst diagnosis, identified misconceptions and points to new approaches. However, in spite of the variety of treatments undertaken, the fertility of diagnosed and treated cases was compromised. It is proposed that prevention, rather than cure, should be a future goal.

Prophylaxis of intravenous catheter-related thrombophlebitis in cattle

Two methods of preventing intravenous catheter-related thrombophlebitis of the jugular vein, using clinical and ultrasonographic criteria, were compared. The first method consisted of minimising bacteriological contamination by the preparation of the skin as if for surgery. The second method involved the daily subcutaneous administration of low doses of heparin to decrease procoagulant activity. The results showed that the preparation of the skin before the placement of an indwelling catheter in the jugular vein and adequate daily maintenance of the catheter were of great importance in the prevention of thrombophlebitis induced by bacteriological contamination. The use of heparin should be limited to cases that require long-term catheterisation or are predisposed to thrombosis or other clotting abnormalities.

Antithrombin-III activity in plasma of healthy and sick cattle

Antithrombin-III (AT-III) activity was determined in the plasma of 32 healthy cows. The range of activities was between 105 and 160 per cent of a human reference plasma; the median activity was 132.5 per cent, and the 5 per cent and the 95 per cent quartiles were 111.1 per cent and 153.9 per cent of the standard. The activity of AT-III was also determined in 82 cows with a variety of internal diseases. In cows with hepatopathy, acute enteritis, generalised peritonitis, blood loss, idiopathic cardiomyopathy, glomerulonephritis and disseminated coagulopathy, the activity of AT-III was lower than in healthy animals. The lower values were due to decreased synthesis, increased consumption, or the loss of AT-III. An acquired deficiency of AT-III appears to favour the development of thrombophlebitis.

Experimental oral transmission of Ehrlichia phagocytophila to calves

Three groups of four calves were used to determine whether Ehrlichia phagocytophila could be transmitted orally to calves via infected milk. Groups 1 and 2 consisted of four-week-old calves and group 3 of newborn calves. The calves in group 1 were fed for several days with milk from cows infected experimentally with E phagocytophila. The calves in groups 2 and 3 were fed 200 ml of whole blood containing E phagocytophila organisms; for group 2 the blood was added to milk before being fed, and for group 3 the blood was added to colostrum before being fed within three hours after birth. Blood samples for haematological, serological and cytological examination, and for polymerase chain reaction (PCR) were collected from all the calves, starting on the first or only day of administration and then every four days for four weeks. The calves of groups 1 and 2 showed no clinical, haematological or serological changes, and there was no direct or indirect evidence of the agent. In contrast, all the calves in group 3 had mild pyrexia and seroconverted on day 8, and in one of them E phagocytophila organisms were visible in leucocytes, and the PCR on the buffy coat was positive on day 8.