Recovery of Mycoplasma agalactiae from mastitic goat milk.

An organism recovered from mastitic milk of a newly freshened goat was identified as Mycoplasma agalactiae. The number of mycoplasmas in the mammary secretions was 6.3 x 10(7) colony-forming units/ml, indicating active infection. This was the second recovery of M agalactiae in the United States, but in contrast to the previous isolate from the joint of a goat reported to be avirulent following experimental inoculation, the large concentration of M agalactiae from mastitic milk is evidence that it possesses pathogenic potential.