Please advise: the pros and cons of feeding magnetic cages to dairy cows

Cows in the feeding process, there will inevitably be accidentally eaten iron, wire, etc., once these things into the cow's stomach, it is likely to hurt the stomach, abdomen, liver and even the heart and other organs, both to the cows to bring great pain, but also affect the economic benefits of cattle farms. Magnetic cage feeders can adsorb these tiny iron slags, avoiding cows suffering from the pain of accidental ingestion of iron. One eight wu one liu jiu seven one eight yo-yo