I may be speaking out of context, since I do not know what Bapa Rao gaari
gEde praSna was. If it is about the etymology of the word mahishi, then
I think palaka is right in saying mahishi has connection to mahaa.
I remember reading that mahaa, mahat, mahi (great land=earth), mahisha,
mahishi are all cognate words, and all these words imply something "great".
mahisha-mRga was originally used for buffalo, and later the word seem to
have continued with this meaning with mRga suffix dropped.
Regards,
Suresh.