Figure 4.

Flow rate influences the potential distress level during euthanasia. (A) The duration of dyspnea is significantly greater in the 10% v/min group compared with the 30% or 50% v/min groups for both cagemates and strangers. (B) Similarly, in both cagemate and stranger groups, mice exposed to 10% v/min CO₂ experienced a longer duration of ataxia compared with other flow rate groups. (C) The number of observed jumps (interpreted as escape attempts) was greater in the 10% v/min group (compared with 30% and 50% v/min groups) only in paired familiar mice. P values were calculated by using 2-way ANOVA followed by Tukey multiple comparison testing. Error bars, 1 SD; ns, not significant.