Foolhardiness

We've induced another avocado stone to grow (actually in this case it was already halfway there when we removed it from the fruit with the root already working its way through a split--irresistable!). It's got three long roots and already one failed shoot and one that's about to produce its first baby leaves. The wire cage we built last time didn't deter Biggle from pruning when Avocado's number was attained, so does anyone have any idea how to stop the cat eating the avocado?