The ear canal as a culture site for demonstration of mycoplasmas in clinically normal goats.
The results of the culture for mycoplasmas of the external ear canal, nares and milk (where applicable) of 7 clinically normal goat herds were compared. In 5 goat herds that had a history of mycoplasma infection with either Mycoplasma capricolum, M. mycoides subsp. mycoides or Mycoplasma sp. GM262G and with clinical signs of arthritis or mastitis the ear canal was the preferred site yielding 32 mycoplasma-positive goats out of 91 goats (35%) sampled whereas the milk samples were negative in all cases and the nares yielding only nonpathogenic M. arginini. Pathogenic Mycoplasma species M. capricolum, M.mycoides subsp mycoides, M. putrefaciens were encountered in the ear canal of 26 goats (29%). Mycoplasmas serologically indistinguishable from isolate GM262G were isolated from ears of goats in 3 herds. In these 5 herds the pathogenic mycoplasma responsible for causing prior disease in each herd was recovered from the ear canal of goats in each herd although additional pathogenic species were also recovered. Pathogenic mycoplasma species were not recovered from any of the 54 goats in the 2 herds without a history of mycoplasma infection. Other mycoplasmas whose pathogenic significance is currently unknown were recovered from all 7 herds. It is suggested that the external ear canal must be considered the prime cultural site for mycoplasmas in clinically normal goat herds and that this may also be the case in cattle. A possible relationship between mites and mycoplasmas in the ears of goats and cattle is discussed.