The capability to remove ammonia through the air flow of a ventilated "closed" cage is already demonstrated by some authors and comparisons with top flow static cages has clearly shown the higher efficiency of the IVC systems.
Influence on the ventilation efficiency, in its attempt to remove ammonia gas, can arise from some features such as type of bedding used and animals' density.
By using 3 different bedding materials and housing in IVC Sealsafe cages ICR mice both stock males and females plus some monogamous pairs with their litter, we verified different ammonia growth behaviours over a period of 14 days.
The choice of the bedding material doesn't seems to be relevant during the first 7-10 days whereas becomes crucial from day 12 to 14.
The proficiency of some beddings to promote a higher growth of urease positive bacteria can be easily overtaken with the appropriate adjustment of the air flow in the cages, but this is possible only if the system provides flexibility of use, related with the complete control of this parameter by the operator.
Pre-weaning survival rate, food intake, growth curve of stock animals and water intake were also considered during the study.