Mastitis control programme in the developing dairy industry of tropical lowland Bolivia.

Mastitis is an important disease in developing dairy industries. This paper describes a commercial mastitis control programme in Santa Cruz, Bolivia, based upon the five-point mastitis control plan and bulk tank somatic cell count (BTSCC) monitoring. Twelve farms which participated on the programme for 6 years are considered. Mean annual BTSCC fell steadily from 1,200,000 cells/ml to 461,000 cells/ml over this time. This progressive improvement was probably a result of increasing use of and attention to detail in mastitis control practices. The control of subclinical mastitis improved in both hand-milked and machine-milked herds, though hand-milked herds consistently produced milk of higher BTSCC. The mastitis programme did not appear to influence the incidence of clinical mastitis. The concludes that a simple mastitis programme based on the five-point plan and BTSCC monitoring can be commercially implemented and effectively control subclinical mastitis in a tropical, developing country.

Field evaluation of an indirect ELISA for detection of brucellosis in lowland Bolivia.

Bovine brucellosis exists endemically at an estimated prevalence of 10% in the developing dairy industry of Santa Cruz in tropical Bolivia. This paper describes field testing of an FAO/IAEA indirect ELISA for brucellosis, as a possible replacement confirmatory test for the complement fixation test (CFT). The ELISA and CFT were compared on sera from 3 cattle populations: a non-vaccinated negative population, an S19-vaccinated negative population, and a brucellosis-positive population of unknown vaccination status. The CFT and ELISA showed excellent specificities of 100% and 98% respectively against the negative non-vaccinated group. The CFT maintained a specificity of 98% against the S19-vaccinated negative group, but ELISA specificity fell to 83% using a cut-off of 20% of positive control, and 94% using a cut-off of 40% of positive control. Against sera from the positive population, the ELISA gave many more positive reactions than the CFT, probably a combination of both higher sensitivity and lower specificity. It is concluded that as Santa Cruz is entering a phase of brucellosis control rather than eradication, the extra sensitivity of the ELISA is not valuable enough to risk a higher level of false positive reactions, especially as S19 vaccination is being increasingly used.