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In most cases, diagnosis of tuberculosis in domestic animals relies on the tuberculin skin test and the presence of gross lesions. A definitive diagnosis based on the isolation and typing of tubercle bacilli from animals is usually beyond the capabilities of laboratories in most developing countries. In this report, which includes the isolation and identification of the causal bacteria, 2 cases of tuberculosis in the swamp buffalo (Bubalus bubalis) are described.Two swamp buffaloes from a herd in north-eastern Thailand had died showing emaciation in May and June 1992, and specimens of lung and liver were submitted to a central veterinary laboratory for routine diagnosis. Tissues for histology were fixed in 10% formalin, paraffin wax-embedded, and sections cut and stained with hematoxylin and eosin. All the tissues had similar numerous granulomatous nodules of various sizes with marked central necrosis and calcification. The necrotic areas were surrounded by infiltrating macrophages, epithelioid cells and a few Langhans' giant cells. Numerous acid fast bacteria in the lesions were demonstrated by Ziehi-Neelsen staining.Isolation and identification of Mycobacterium species from the tissue specimens was undertaken using a simplified method (Jarnagin and Payeur, 1989) employing Herrold egg yolk medium (HEY, with 2.6% glycerin) and Ogawa egg medium (with 2% glycerin). The tissues were broken down by grinding in a sterile mortar and pestle with nutrient broth containing 0.004% phenol red. The suspension was treated with an equal volume of5N NaOH for l0 min, then with 6N HCI. The suspension was then neutralised with 1N NaOH. The sediment obtained after centrifuging (1650 g for 20 min) was inoculated onto the media and incubated at 37°C. Primary colonies of acid fast organisms appeared only on HEY on which the lung and liver of one animal and the lung of the other were inoculated. These were subcultured on the same media and incubated at 25, 37 and 45°C. An identification of Mycobacterium boris was made based on the following characteristics: slow growth (colony appearance time of 3 weeks) at only 37°C, non-pigmented, rough and translucent colonies on slants, granular growth and presence of short-ragged cording in the Proskauer and B~h medium (Anon, 1985), and niacin test (Kyokuto Pharmaceutical Industry, Tokyo) negative. The HEY medium was superior to the Ogawa medium for primary isolation. The isolates were not dysgonic on the medium containing 2-6% glycerin.Additional biochemical tests were carded out for further confirmation of the isolates and the results were as follows: nitrate reduction (Virtanen, 1960) negative, catalase (68°C, 20min) (Kubica and Pool, 1960) negative, Tween 80 hydrolysis (Wayne, 1962) negative, arylsulfatase (Wayne, 1961 negative, and urease production (Toda et al., 1960) negative. These results were compatible with those of M. boris reported by Roberts et al. (1991).The simplified method described above was effective for the isolation and identification of M. boris and could be applied in labo...

The objective of this field study was to describe the temporal pattern of dairy cattle health and production and associated risk factors in rural small-holder communities in northern Vietnam, one of the target areas of the government's dairy development programme. A total of 99 dairy farms (11 per commune) were recruited from 9 of 32 communes in Ba Vi District, Ha Tay Province, using random two-stage cluster sampling. All dairy cattle present on the selected farms were included. After the initial questionnaire survey was conducted, farms were visited to collect follow-up information at 3-monthly intervals over a period of one year. The results suggest that offtake as well as mortality are important productivity indices because farmers sell or slaughter dairy cattle that are in poor health at low prices during summer months. Changes in relation to the farming operation suggest that for the farmers adopting dairy production it has become one of the main agricultural activities.