Abstract
Young caesarian-derived rats, sharing cages with conventional rats, developed chronic respiratory disease after 2 months if the conventional rats were young, and after 1 month if they were old. Old caesarian-derived rats developed the disease after only 2 weeks of exposure, irrespective of the age of the cage mate.
In long-term experiments, caesarian-derived rats acquired chronic respiratory disease from conventional rats even when kept separately in wiremesh cages adjacent to theirs. If caesarian-derived rats were kept in a separate cage 4 feet away from infected stock more than 1/3 of the rats did not develop chronic respiratory disease, and in the remainder the disease was retarded.
When facilities are restricted and it is desirable to use caesarian-derived stock these, if young, could be housed with young conventional rats for up to 2 months with little risk of developing chronic respiratory disease.