What is ferrous sulphate?
Ferrous sulphate is the sulphate salt of divalent (ferrous) iron. The heptahydrate (FeSO₄·7H₂O) forms pale green crystals with about 19–20% iron; the dried monohydrate (FeSO₄·H₂O) is a grey-white to beige powder with about 30% iron and is the form preferred in premixes because it is more concentrated and flows better.
Ferrous sulphate is water-soluble and its iron is well available, so it serves as the reference source in iron bioavailability studies. Ferrous iron gradually oxidises to the ferric form in the presence of moisture and air.
What does iron do in animal feed?
- Oxygen transport: iron is the central atom of haemoglobin in red blood cells and of myoglobin in muscle.
- Energy metabolism: iron-containing cytochromes and iron-sulphur proteins are essential for cellular respiration.
- Growth and immunity: adequate iron supports normal growth and immune function in young animals.
- Piglets: piglets are born with small iron reserves and sow's milk is low in iron, so without supplementation they quickly develop iron-deficiency anaemia. Iron is commonly given by injection soon after birth, and dietary iron in creep and starter feeds supports iron status after that.
- Calves: milk and milk replacers are low in iron, so the iron level of milk replacers and calf starters needs attention.
Forms of iron in feed
- Ferrous sulphate monohydrate: about 30% Fe; the most common premix form.
- Ferrous sulphate heptahydrate: about 19–20% Fe; prone to caking and less used in premixes.
- Ferrous carbonate: an alternative inorganic source; its availability depends on the product.
- Iron oxides: poorly available as an iron source and used mainly as colourants.
- Organic iron: iron chelates of amino acids or glycine and iron proteinates.
How is the iron requirement assessed?
Many feed raw materials, inorganic phosphates, limestone and drinking water already contain considerable iron, and adult ruminants and most finishing animals rarely need much supplemental iron. Supplementation is focused on young, fast-growing animals and on species and stages where the diet supplies little available iron.
Excess iron is not harmless: it can reduce the absorption of copper, zinc and manganese and acts as a pro-oxidant. The supplemental level is therefore set by the nutritionist according to species, age and the iron already present in the diet. Maximum total iron levels in complete feed are regulated in many countries; local regulations and the product label prevail.
Quality criteria
- Guaranteed iron content, verified by analysis, and a high proportion of iron in the ferrous form.
- Undesirable substances: lead, cadmium and arsenic within legal limits.
- Free acidity and moisture, which affect caking and stability.
- Stability in the premix: ferrous sulphate can accelerate the oxidation of sensitive vitamins, so premix design and storage conditions matter.
- Certificate of analysis (CoA) and lot traceability.
CTF Premix and ferrous sulphate
Ferrous sulphate can be included in CTF Premix's mineral and vitamin-mineral premixes according to the customer's formulation, with the iron level matched to the species and the iron already supplied by the diet. Premixes are produced at our Ankara facility under ISO 9001:2015 and GMP, and every lot has a certificate of analysis and lot traceability.
This page is for general information. Inclusion rates and product choice should be decided with a nutritionist, taking into account the species, the feed formulation and the applicable regulations.