Hi Arvind and Daya,
I rechecked all universes, connections and Webi reports. All are fine. Also, I imported universes in designer, refreshed them and again exported to repository. I also checked whether WebI reports are enabled as "Refresh on open". All are good. But still dashboard performance is poor in PROD as compared of Dev.
WebI reports are working fine. They are taking almost same amount of time in both BO DEV and BO PROD. I think the issue is with LiveOffice. Redeploying war file may resolve the error but I am not sure about it.
Thanks,
Aashutosh