Can calves contract mycoplasma from mycoplasma-contaminated sand bedding?

Probably not, according to research from Utah State University and reported in the March issue of the Journal of Dairy Science.

In the study, six pre-weaned Holstein bull calves were either bedded with “clean” sand and six more were bedded with sand previously positive for Mycoplasma bovis at a dairy farm. Bedding sand was cultured weekly; calf nasal and ear swabs and sera were collected weekly, tracheal swabs were collected monthly.

At the end of the study, all 166 tracheal swabs, nasal and ear swabs, and postmortem tests from all calves were negative for mycoplasma. All 94 sera were negative for M. bovis-specific antibody. No pathology suggestive of mycoplasma disease was detected. The probability of mycoplasma detection, if an exposed calf had become infected four weeks after exposure, ranged between 97 and 99 percent, depending on time of exposure for individual calves.

The researchers conclude that there was no evidence that sand bedding contaminated with M. bovis might serve as a source of transmission to young dairy calves. However, the possibility of infection through the teat ends of lactating cows, and perhaps pre-fresh heifers housed on sand, needs further investigation.