LABORATORY DIAGNOSIS OF BOVINE TUBERCULOSIS

Lesions of suspected bovine tuberculosis were examined by culture, histopathology and auramine-O (AO) stained smears and the findings correlated with field aspects of the disease. Of 642 lesions considered to be tuberculous, 62.0% yielded M. bovis and 4.5% other mycobacteria (OM). M. bovis and OM were recovered also from 0.6% and 3.6% respectively of 165 cattle which gave tuberculin reactions but had no visible lesions at slaughter. Of 262 lesions in which a histopathological diagnosis other than tuberculosis was made, 1.5% and 3.0% yielded M. bovis and OM respectively. All OM isolates tested belonged to the Mycobacterium-avium-intracellulare-scrofulaceum (MAIS) complex with a predominance of serotype 2. A good relationship was found between the recovery of mycobacteria and histopathology but examination of smears revealed 22.0% apparent false negatives. Apparent false negative culture results were also reported for 35.8% of lesions positive on histopathology and smear examination. The majority of herds yielding M. bovis contained reactors to the tuberculin test and many of these had lesions of tuberculosis. In contrast, herds yielding OM seldom contained reactors to the tuberculin test and rarely reactors with tuberculous lesions. The thoracic cavity was the main site of lesions from infections by M. bovis and OM.     

SONOGRAPHIC APPLICATION IN THE DIAGNOSIS OF PYELONEPHRITIS IN CATTLE

Nineteen cattle with pyelonephritis were examined sonographically. A 3.5- and 5.0-MHz convex transducer was used for percutaneous and a 5.5-MHz linear scanner for transrectal examination. Ultrasonographic changes included enlarged kidneys, echogenic material, and flocculent fluid within a dilated and deformed renal sinus and a poor cortical medullary differentiation. Azotemia was detected in 10 and hematuria and proteinuria in all animals. Microbial culture revealed Corynebacterium renale in eight and Escherichia coli in five cattle. Sonography supplemented the clinical examination and clinicopathological analysis by providing additional information on renal disease in these patients.     

PRELIMINARY OBSERVATIONS ON THE PRODUCTIVITY OF FEMALE CATTLE IN THE KIMBERLEY REGION OF NORTHWESTERN AUSTRALIA

Three experiments were done to determine the influence of supplementary feeding with crushed whole cotton seed and weaning on the productivity of breeding female cattle under range conditions in the Kimberley region, north-western Australia. In the first experiment, supplementary feeding cut losses of breeding cows from 47% to nil, and increased calf turn-off from 18% to 58%, in a sample of cattle from Argyle Downs cattle station during a severe dry season. In the second experiment, weaning calves at 4–6 months of age reduced weight loss in supplemented cows, from 21 to 8% over the last 100 days of the dry season, although the subsequent growth of supplemented weaned calves was inferior to that of non-weaned calves. In the third experiment, weaning of calves had no effect on body weight changes in supplemented cows, although non-weaned calves gained significantly faster than weaned supplemented calves. Control of cattle tick infestation by spraying increased blood haematocrit and haemoglobin values, but had no effect on total plasma proteins. A survey of feral cattle in the Kimberley area showed depressed blood haeboglobin, haematocrit and plasma protein values in breeding cows compared with other classes of cattle.     

奶牛新孢子虫病诊断方法研究进展

新孢子虫病是导致奶牛流产的主要原因之一，给奶牛业造成很大的经济损失。各国学者对新孢子虫病的诊断方法进行了大量的研究工作。本文对奶牛新孢子虫病的临床诊断、病原学诊断、血清学诊断及分子生物学诊断方法的研究进展进行了综述。