Not all android devices have an inbuilt Cast function. I have a Tribute HD and there is no option to cast or mirror.
However, I don't think Cast would necessarily be worth it. UPnP/DLNA works with far more formats and devices. It transcodes only when it has to based on decoder support from the receiver (eg. Your TV, Roku, Fire TV, etc).
I might be missing something, but my experience with Cast is with any device other than a Chromecast has been less than stellar. DIAL is the fallback and it's quite the crap shoot, if you don't have a relevant app on your receiver. While decoder support varies wildly, especially on generic streaming boxes, the main players have the vast majority of formats down.