[Use of selective nutrient media for isolating the streptococci that cause mastitis]. / Prilozhenie na niakoi selektivni khranitelni sredi za izolirane na streptokoki, prichiniavashti mastit.

Studied was the diagnostic value of the liquid enriched nutrient medium - Streptococcus broth with kanamycin, used for the isolation of Sc. agalactiae and other mastitis streptococci in individual milk samples as well as that of blood dextrose agar with polymyxin + Staphylococcus toxin seeded after Koch for the isolation of Sc. agalactiae and other hemolytic streptococci in pooled cow milk. Direct seedings in thallium sulfate-crystal violet-B toxin blood agar (TKT agar) were used as a control. It was found that the enriched Streptococcus broth with kanamycin yields growth of 0.23 per cent more Sc. agalactiae organisms and 1.82 per cent other mastitis streptococci in individual milk samples as compared to the TKT agar. The blood dextrose agar with polymyxin seeded after Koch demonstrates fivefold more Sc. agalactiae in pooled cow milk as against the direct seedings in TKT agar, and it can be used to confirm the infection on the farms.

[Indirect methods of determining the amount of cellular elements in bulk cow's milk]. / Prouchvaniia vurkhu indirektni metodi za opredeliane kolichestvoto na kletuchnite elementi v sbornoto krave mliako.

Comparative studies have been carried out to establish the practical value of three indirect methods--Whiteside, Bernburg, and the antiformin one--intended for the rapid determination of the somatic cell count in pooled cow milk. A total of 556 samples of milk from various sources have been studied. The data obtained with the use of the direct method of Prescott and Breed served as control values of the cell elements in milk. A conclusion has been made that the test after Whiteside is the most appropriate one for the rapid determination of the cell count in pooled cow milk: it gives positive results in 100 per cent of the investigated samples having a count of more than 500000 cells. The use of this method is suggested in the case of detecting farms where mastitis is a problem.