Figure 4.

Proportion (%) of cages that reached threshold levels of either (A) 50 ppm or (B) 25 ppm ammonia during the 2-wk measurement period. A cage was considered to exceed a threshold when above-threshold readings were obtained from at least 2 measurement devices. Aspen cages exceeded all thresholds earlier than other materials. Above-threshold readings in corncob cages were delayed until near the end of the measurement period. In contrast, the novel cellulose materials largely prevented above-threshold measurements, compared with other bedding types.