Comparative prevalence of tuberculosis in two dairy herds in India.

Holstein Friesian cows and their crossbred progeny on a farm in northern India were tested for tuberculosis (TB) infection using a single intradermal tuberculin test. The results showed that the animals persistently harboured TB infection for periods of two to four years. The recent comparative intradermal tuberculin test revealed that at least five out of nine of these cattle reacted positively to bovine tuberculin purified protein derivative. A high (15.76%) prevalence rate resulted because none of the infected animals had been segregated or culled from the herd since the first incidence was detected in 1992. In contrast, another farm in western India that practiced segregation and culling was able to contain the level of prevalence of TB between 0.65% and 1.85%. These findings call for stricter regulations on the management of TB at farm, state and country level and a revision in the mode of breeding programmes adopted by farms.