The EU has legislation also as a result of the BSE crisis (related to recycling of - infected - sheep material). So check the EU website for their rules.
In my view the potential is considerable. As an example, in the Mediterranean agriculture, waste from olives, after the extraction of oil offers the possibility of developing products for animal feed. Similarly, waste from citrus fruits after being pressed for fruit juice can be used for animal feed among other interesting applications (essential oils, cosmetics, etc). Industry in collaboration with universities are performing promising research in these areas.
The issue of recycling waste as feed is really huge and promising: from agricultural waste to food waste. I would like to focus on food waste, because from food grade material to feed grade material should be less risky for animals, human health and environment.
In Italy, following European recommendations, there are Italian recommendations to reach the EPA Food Recovery Hierarchy model: