This article has not yet been professionally approved. The information is based on the sources listed below.
Mineral feed without iron or without selenium: when does it make sense?
If you are looking for a mineral feed without iron, selenium or iodine, you usually have a reason. Here you can put it in context: what the hay supplies, what the analysis needs to show and when leaving a substance out makes sense.
The short answer
A mineral feed without iron is an obvious choice for many horses, because forage usually supplies plenty of iron and iron deficiency is rare in adult horses 1. For selenium and iodine, the answer depends on the hay: depending on location, the selenium content of forage ranges from almost zero to more than the requirement 2. Without a lab value, leaving it out is the more cautious choice, but it may leave a gap.
First: why are you looking for this product?
The search for a mineral feed without a particular substance can have very different reasons. What you should do next depends on them.
| Starting situation | What you clarify | Next step |
|---|---|---|
| Hay analysis shows a high content | Measured value and daily amount | Choose a product without this additive and check the balance |
| Another product already supplies the substance | Sum of all sources | Avoid double supply |
| Recommendation from your vet | Specific instruction from the practice | Follow the instruction, calculate the ration around it |
| General uncertainty | Is there a measurement or calculation? | Check the ration and hay first |
Common starting situations and the appropriate next step for each.
Mineral feed without iron
Forage usually supplies plenty of iron. Iron deficiency is rare in adult horses; supplementation is only indicated for a specific reason 1. For many horses, a mineral feed without added iron is therefore an obvious choice.
Legally, iron compounds are authorised as feed additives; horses are not named separately in the maximum contents 3. Whether the iron content of your hay was measured depends on the scope of analysis you ordered; check this in the order before you assume a value 4.
Mineral feed without selenium
Selenium is the most difficult case when it comes to leaving a substance out. The content in forage depends on the soil: grass forage samples averaged 0.194 ppm, with a range of 0 to 1.2 ppm 2. The requirement is around 0.1 mg per kg of feed dry matter, and the margin to excess is narrow 56.
It follows that without a measured value you cannot say whether selenium is missing or already supplied in plenty. A product without selenium avoids oversupply but may leave a gap. With a lab value, the question can be answered; the permitted total content is 0.50 mg per kg of complete feed with 12% moisture 7.
Mineral feed without iodine
Iodised salt easily covers the iodine requirement, and except in regions that are very low in iodine, additional iodine supplementation is usually not necessary 2. Kelp and seaweed products, on the other hand, are a common source of excess iodine; the thyroid gland of unborn foals is particularly sensitive 8. The permitted total content for equids is 4 mg iodine per kg of complete feed with 12% moisture 9.
“Without” does not mean “free from”
A product without a particular additive can still contain small amounts of that substance, because ingredients and carriers bring natural contents with them. For supply, natural and added amounts count together 10. What matters is therefore the balance of the whole ration, not the label of a single product.
How Equivora handles such requests
A substance only goes into an Equivora mix if the ration calculation shows a gap. We only include selenium and iodine with a reliable lab value. If there is no hay analysis, a mix is still possible, but without targeted addition of selenium and iodine. An iron gap is rarely to be expected because of the contents in forage 1.
Key takeaways
Frequently asked questions
Is a mineral feed without selenium healthier?
Not as a general rule. It avoids additional selenium intake, but it does not close a gap either. Whether your horse needs selenium is shown by the selenium content of the hay together with the other feeds 25.
Is there iron-free mineral feed?
There are products without added iron. They are usually not completely iron-free, because carriers and ingredients bring natural contents with them. For the balance, added and natural contents count together 10.
Can I supplement selenium separately?
Yes, if a measured value shows a gap and the amount fits the overall ration. The permitted total content is 0.50 mg selenium per kg of complete feed with 12% moisture; a separate supplement has to be measured against this in the same way 7.
Sources & studies
The content is based on the references listed below. It does not replace individual veterinary or feeding advice.
Show list of sources (10)
- Merck Veterinary Manual: Nutritional Diseases of Horses (Eisen)Iron deficiency is rare in adult horses; forage practically always supplies plenty of iron, and supplementation is only indicated where there is a specific reason
- Merck Veterinary Manual: Nutritional Requirements of Horses and Other EquidsSummary of the NRC recommendations: water requirement 5 litres per 100 kg body mass per day at maintenance, sweat losses of around 3.1 g sodium, 5.3 g chloride and 1.6 g potassium per litre, salt recommendation 1.6–1.8 g per kg feed dry matter at a maximum of 6% of the ration; from a 50% forage share potassium is adequately covered. Also covers the selenium requirement (0.1 mg/kg feed dry matter or at least 1 mg/day for a 500 kg horse, selenium as a component of glutathione peroxidase together with vitamin E) and the strong location-dependent variation of selenium in forage (grass forage on average 0.194 ppm, range 0–1.2 ppm); some regions are markedly low in selenium and may need supplementation. Also gives the iodine requirement (0.35 mg/kg feed dry matter, mares in late pregnancy 0.4), iodine poisoning of pregnant mares from around 40 mg/day, documented goitre cases in mares and their foals associated with large amounts of dried seaweed (kelp), that iodised salt easily covers the requirement, and that iodine supplementation is usually unnecessary except in severely iodine-deficient regions
- Durchführungsverordnung (EU) 2017/2330Authorisation of iron compounds (3b101 ff.); total maximum content of iron per kg complete feed (12% moisture) according to the consolidated version of 25 September 2022: pets 600, other species 750. Horses are not listed separately.
- LUFA Nord-West: Untersuchungsauftrag Pferdefutter 2026/27p. 1: analysis packages and prices per sample plus VAT; p. 2: scope of analysis, sample quantities and shipping. Prices for 2026/27, checked on 28 September 2026; not an Equivora offer.
- NRC – Nutrient Requirements of Horses, 6th ed.International reference for the nutrient requirements of horses (National Research Council)
- GfE (2014) – Empfehlungen zur Energie- und Nährstoffversorgung von PferdenSpecialist reference in German-speaking countries (GfE, German Society of Nutrition Physiology), Committee for Requirement Standards
- Durchführungsverordnung (EU) 2019/49Authorisation of sodium selenite (3b801), coated granulated sodium selenite (3b802) and zinc-L-selenomethionine (3b818) for all animal species; total maximum content of selenium 0.50 mg/kg complete feed (12% moisture), for 3b818 at most 0.2 mg/kg of added organic selenium. Authorisation expires according to the Annex on 3 February 2029.
- Merck Veterinary Manual: Goiter in AnimalsStandard veterinary reference work (endocrinology): goitre (struma) occurs both with iodine deficiency (low hormone levels → increased TSH → hyperplasia) and with iodine excess (high iodine concentrations inhibit organification and hormone release); the foetal thyroid reacts more sensitively than the adult one; foals receive excess iodine in the womb and via milk, because mares on an iodine-rich ration secrete more iodine into their milk; mineral supplements containing kelp are a common source of iodine excess; goitrogenic plants (cabbage, rapeseed, kale, turnips, soya) can promote goitre. Goitre is therefore not a clear indicator of iodine supply.
- Durchführungsverordnung (EU) 2015/861Authorisation of potassium iodide, anhydrous calcium iodate and coated granulated calcium iodate (identification numbers 3b201 to 3b203); total maximum content of iodine for equids 4 mg/kg complete feed (12% moisture). Under other provisions, the Annex additionally gives a recommended maximum content of 3 mg/kg (not the binding value). Authorisation expires according to the Annex on 24 June 2025; for the renewal procedure see the EFSA opinion. According to the EU Register of Feed Additives (as of 15 October 2026), an application for renewal under Art. 14 of Regulation (EC) No 1831/2003 has been submitted; the authorisation remains valid.
- Verordnung (EG) Nr. 1831/2003Feed additives – authorisation and use; “daily ration” based on 12% moisture (Art. 2(2)(f)), renewal of authorisation and automatic continuation (Art. 14(4)), general conditions of use (Annex IV: natural plus added amount; complementary feed, diluted as specified, at most at the level for complete feed). Link to the current EUR-Lex consolidated version (as of 27 March 2021).