Identification of yeasts from infected bovine mammary glands and their experimental infectivity in cattle.

Cultures of yeast (n = 91) were obtained from infected mammary glands of cows in New York and Iowa. Of the isolants, 78% belonged to the genus Candida. Eleven Candida species were found, with C tropicalis being the most frequently isolated species and C rugosa being the 2nd most frequently isolated species. Five species of Candida and an isolant of Cryptococcus lactativorus were used for experimental inoculation of mammary glands of healthy cows. Of glands inoculated with C tropicalis, C rugosa, C parapsilosis, and Crypt lactativorus, 100% became infected. Only 3 of 8 glands inoculated with C krusei and 1 of 5 glands inoculated with C albicans became infected. Recovery of organisms from infected glands occurred on an average of 7.4 days after inoculation, and infections were eliminated spontaneously from 10 to 30 days after inoculation. Clinical differences were not noticed in the cows or glands regardless of the species of yeast used for establishing infection.