Tyndalized milk of goat, cow, and buffalo was found to be a potential substitute for fetal bovine serum (FBS) in the medium for the cultivation of Leishmania donovani promastigotes. The numbers (means) of promastigotes reached 2.6 x 10(7), 2.3 x 10(7), and 2.1 x 10(7)/ml, respectively, in the medium supplemented with 10% milk of goat, cow, and buffalo, in comparison to 1.9 x 10(7)/ml in the con...