Sorry, I haven't heard of canola. I use a pre-mixed coarse mix which has rolled peas, maize, and other grains and ewe pencils in it. Do you have access to ewe pencils with a stated protein content? Here we get 16% and 18% - the latter for ewes approaching lambing. It is probably a bit more expensive than straight grains, but easier to work out just what they are getting, bioth proteins and minerals. We also give a molassed mineral lick.