# Ferrous Sulfate: veterinary dose and monograph > Ferrous Sulfate is a veterinary drug. Oral iron for confirmed iron-deficiency anaemia (usually chronic external blood loss) and to support erythropoietin therapy. Indications include iron-deficiency anaemia; iron support during erythropoietin therapy; haematinic (large animals). This monograph lists 6 reference doses for dogs, cats, cattle, horses, sheep and pigs, each with route, frequency and source, plus meat and milk withdrawal periods for food animals. Source: https://vetmasterji.com/drugs/ferrous-sulfate · Last reviewed: 2026-10-01 ## At a glance - **Drug class:** Veterinary drug - **Also known as:** Ferrous sulphate, Oral iron - **Species with doses:** Dogs, Cats, Cattle, Horses, Sheep and Pigs - **Routes:** PO - **Last reviewed:** 1 October 2026 ## Indications - Iron-deficiency anaemia - Iron support during erythropoietin therapy - Haematinic (large animals) ## Ferrous Sulfate dose by species Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them. ### Dogs *Ferrous Sulfate doses for dogs* | Indication | Dose | Route | Frequency | Duration | | --- | --- | --- | --- | --- | | Iron-deficiency anaemia | 100–300 mg per dog PO once daily | PO | q24h | — | - Iron-deficiency anaemia: Papich 5e and Plumb’s p.519: 100–300 mg per dog per day (with a meal to reduce GI upset — absorption is better apart from food; Harvey). ### Cats *Ferrous Sulfate doses for cats* | Indication | Dose | Route | Frequency | Duration | | --- | --- | --- | --- | --- | | Iron-deficiency anaemia / erythropoietin support | 50–100 mg per cat PO once daily (5–50 mg; or 10 mg/kg) | PO | q24h | — | - Iron-deficiency anaemia / erythropoietin support: Papich 5e: 50–100 mg per cat q24h. Plumb’s p.519: 50–100 mg per cat daily (Macintire; Vaden); 5–50 mg (DiBartola & Chew); 10 mg/kg (Macintire). Many cats do not tolerate oral iron — iron dextran 50 mg IM every 3–4 weeks is an alternative. ### Cattle *Ferrous Sulfate doses for cattle* | Indication | Dose | Route | Frequency | Duration | Withdrawal | | --- | --- | --- | --- | --- | --- | | Haematinic | 8–15 g per animal PO daily for ≥2 weeks | PO | q24h | — | Withdrawal NOT established — treat as extra-label | - Haematinic: Plumb’s p.519 (Adams 1988). ### Horses *Ferrous Sulfate doses for horses* | Indication | Dose | Route | Frequency | Duration | | --- | --- | --- | --- | --- | | Haematinic | 2–8 g per horse PO daily for ≥2 weeks | PO | q24h | — | - Haematinic: Plumb’s p.519 (Adams 1988). True iron deficiency is rare in horses — confirm before supplementing. ### Sheep *Ferrous Sulfate doses for sheep* | Indication | Dose | Route | Frequency | Duration | Withdrawal | | --- | --- | --- | --- | --- | --- | | Haematinic | 0.5–2 g per sheep PO daily for ≥2 weeks | PO | q24h | — | Withdrawal NOT established — treat as extra-label | - Haematinic: Plumb’s p.519 (Adams 1988). ### Pigs *Ferrous Sulfate doses for pigs* | Indication | Dose | Route | Frequency | Duration | Withdrawal | | --- | --- | --- | --- | --- | --- | | Haematinic | 0.5–2 g per pig PO daily for ≥2 weeks | PO | q24h | — | Withdrawal NOT established — treat as extra-label | - Haematinic: Plumb’s p.519 (Adams 1988). ### Buffalo No buffalo-specific doses are on file, so buffalo are dosed as cattle. *Ferrous Sulfate doses for buffalo* | Indication | Dose | Route | Frequency | Duration | Withdrawal | | --- | --- | --- | --- | --- | --- | | Haematinic | 8–15 g per animal PO daily for ≥2 weeks | PO | q24h | — | Withdrawal NOT established — treat as extra-label | - Haematinic: Plumb’s p.519 (Adams 1988). ## Contraindications Haemolytic anaemia or iron overload; GI ulceration. Do not give with antacids, tetracyclines or fluoroquinolones (chelation). ## Adverse effects - GI upset, nausea, dark stools - Constipation ## Formulations and products - 325 mg tablet (65 mg elemental iron) ## Before you use this dose > **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision. ## Other hormones, emergency drugs, supplements and other drugs - [Enoxaparin](https://vetmasterji.com/drugs/enoxaparin) - [Epinephrine](https://vetmasterji.com/drugs/epinephrine) - [Erythropoietin (Epoetin / Darbepoetin)](https://vetmasterji.com/drugs/erythropoietin) - [Estriol](https://vetmasterji.com/drugs/estriol) - [Finasteride](https://vetmasterji.com/drugs/finasteride) - [Fludrocortisone](https://vetmasterji.com/drugs/fludrocortisone) - [Flumazenil](https://vetmasterji.com/drugs/flumazenil) - [Fluoxetine](https://vetmasterji.com/drugs/fluoxetine) ## Frequently asked questions ### What is the dose of Ferrous Sulfate for dogs? Reference doses for Ferrous Sulfate in dogs: 100–300 mg per dog PO once daily PO q24h (Iron-deficiency anaemia). Confirm against the label and the patient before use. ### What is the dose of Ferrous Sulfate for cats? Reference doses for Ferrous Sulfate in cats: 50–100 mg per cat PO once daily (5–50 mg; or 10 mg/kg) PO q24h (Iron-deficiency anaemia / erythropoietin support). Confirm against the label and the patient before use. ### What is the dose of Ferrous Sulfate for cattle? Reference doses for Ferrous Sulfate in cattle: 8–15 g per animal PO daily for ≥2 weeks PO q24h (Haematinic). Confirm against the label and the patient before use. ### What is the withdrawal period for Ferrous Sulfate? Cattle, PO (Haematinic): Withdrawal NOT established — treat as extra-label; Sheep, PO (Haematinic): Withdrawal NOT established — treat as extra-label; Pigs, PO (Haematinic): Withdrawal NOT established — treat as extra-label. Follow the product label and national regulations where they differ. ### When should Ferrous Sulfate not be used? Haemolytic anaemia or iron overload; GI ulceration. Do not give with antacids, tetracyclines or fluoroquinolones (chelation). ### What are the side effects of Ferrous Sulfate in animals? GI upset, nausea, dark stools; Constipation. ## Sources - Plumb's Veterinary Drug Handbook - Papich 5e — Ferrous Sulfate - Papich, Papich Handbook of Veterinary Drugs, 5th edition --- VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.