I may not understand this correctly, but it looks like you assessed the animals (your DV) on a 4 point scale. ANOVA, like regression, requires an interval dependent variable and it is unlikely this will occur with just 4 levels.

Are you doing repeated measures ANOVA (which seems logical since you are tracking changes after an intervention)? I am also unclear when you shifted from two to one way ANOVA which variable you left out?

It might be you are using a more complex design than I am familiar with, if so I appologize for the confusion above.