There is obviously a long tradition of trying to stop the negative effects of invasive species, especially as it affects livestock and crops. Sometimes with chemicals, sometimes by introducing "natural enemies" in the environment, and now also as in your example by sometimes teaching livestock to avoid the new menace. Many times causing other, sometime serious, problems instead.

I'm not saying let nature have its course at all times, only that over time nature will likely solve the problem of an invasive species in its own way, and we should learn to expect it and work with it.

I think with cane toads, the lethality and sheer number has very different implications. There are many species in Australia that are on the brink of extinction, whereas in other continents that have been affected longer by human intervention the species loss has already happened.