Cattle is essentially beef, implemented as a GObject–based shared library, and with more features.
Don't count on the last part just yet.
Please note that Cattle is still considered experimental software; you'll know it is good enough when I'll port beef to it.
Features
At the moment, pretty much the same as the standalone interpreter.
Stable version
There are no stable releases of Cattle. If you want to try it, you have to use a development version.
Development version
The current development version of Cattle is 0.9.1, 380KB.