Well maybe due to my clumsyness with the English language did not make it clear what I wanted to say above.
All orc females in the vanilla game use the male walk (stride). Have a look yourself and go in any orc camp and watch the females there. It is because in the CK the orc race females use the behaviour graph of the male orcs (Actors\Character\DefaultMale.hkx)
https://picasaweb.google.com/lh/photo/bnPoO9eOB5RvfCWn3moCgNMTjNZETYmyPJy0liipFm0?feat=directlink
For comparison, this is the female Nord race:
https://picasaweb.google.com/lh/photo/QCpFCm_2chbBM6DWDzZ1R9MTjNZETYmyPJy0liipFm0?feat=directlink
As I mentioned already, this seems to be a game bug, because some of the orc females who have a "manly" job, have the "opposite gender anims" checked, although the female orc race already uses these.
https://picasaweb.google.com/lh/photo/OEzJGYjvrEIDbRUoRmZeP9MTjNZETYmyPJy0liipFm0?feat=directlink
*sigh* I wish I could write it down more comprehensable.