Copper sulphate

Copper sulphate (all forms including pentahydrate) is a controversial ingredient in dog food. It widely used as a copper supplement in pet foods and is AAFCO approved but in the EU, pure copper sulphate is classified as 'harmful' and 'dangerous to the environment' as well as being an 'irritant'. Dogs need copper but they cannot make it themselves so it must be taken in through the diet. Although all dog foods naturally contain a certain amount of copper from the raw ingredients, additional copper is routinely added as part of the multi-mineral supplement found in almost all dog foods. For this reason it is often listed as 'minerals' and may not necessarily feature on the ingredients list. The levels of copper sulphate used in dog foods are far below those generally regarded as dangerous and should therefore not cause any problems. Of course, copper sulphate also has a lot of critics including a number of pet food manufacturers that choose to avoid copper sulphate by using alternative copper supplements like copper gluconate or copper carbonate. Chelated copper (often listed as copper amino acid complex or copper proteinate) is widely regarded as the safest and most absorbable copper supplement.