Feed grade ammonium chloride is a high-purity form of the same salt, used in ruminant nutrition for a physiological rather than a nutritional purpose. It is fed to acidify urine and to lower the dietary cation–anion difference of a ration. Feed grade is defined by tightened purity and by contaminant limits, because the material enters the food chain — the specification, not the chemistry, is what distinguishes it from the agricultural product.
Substance identity
| Chemical name | Ammonium chloride |
| Synonyms | Sal ammoniac, ammonium muriate |
| Formula | NH₄Cl |
| CAS | 12125-02-9 |
| PubChem CID | 25517 |
| Molar mass | 53.49 g/mol |
| Appearance | White crystalline powder or fine granules; feed grade should be white, without the off-white cast tolerated in agricultural material |
Specification
| Parameter | Value | Basis |
|---|---|---|
| NH₄Cl content, dry basis | ≥ 99.3 % | Typical commercial range |
| Moisture | ≤ 0.5 % | Typical commercial range |
| Heavy metals, as Pb | ≤ 10 mg/kg | Typical commercial range |
| Arsenic (As) | ≤ 2 mg/kg | Typical commercial range |
| pH, 5 % solution at 25 °C | 4.5–6.0 | Typical range |
| Appearance | White, free-flowing | — |
The values above are typical commercial specifications. The binding limits are those set by the feed legislation of the country of use, which differ between jurisdictions and are periodically revised. Where a supplier specification and a regulatory limit differ, the regulatory limit governs. Confirm the current authorisation status of ammonium chloride as a feed additive in the destination market before use.
Properties
Freely soluble in water, approximately 37 g per 100 g at 20 °C, so it disperses readily in liquid feeds and drinking water. Dissolution is endothermic at about +14.8 kJ/mol. Solutions are acidic, pH 4.5–6.0 at 5 %, because NH₄⁺ has a pKa of 9.25 and hydrolyses. Moderately hygroscopic, with a critical relative humidity near 77 % at 30 °C — sufficient to cause caking in premix storage in humid climates. The salt has a strongly salty, sharp taste, which is the source of its palatability limitation.
Applications
Urinary acidification and urolithiasis. In male sheep, goats and feedlot cattle on high-concentrate rations, mineral precipitates can form in the urinary tract and obstruct it. Solubility of the relevant phosphate precipitates is pH-dependent, so lowering urine pH reduces stone formation. Ammonium chloride achieves this because the ammonium ion is metabolised and excreted as urea, leaving the chloride as a net acid load that the animal must excrete renally.
DCAD in transition dairy cows. Dietary cation–anion difference is the balance of absorbed cations and anions in a ration. Feeding anionic salts before calving lowers DCAD, induces a mild compensated metabolic acidosis, and improves the mobilisation of calcium from bone and its absorption from the gut — reducing the risk of periparturient hypocalcaemia. Ammonium chloride is one of the anionic salts used for this purpose.
Both applications depend on the ration and on the animal, must be formulated by a qualified nutritionist, and are normally monitored by measuring urine pH rather than by assuming an inclusion rate works.
Handling and storage
Store dry and sealed, separately from agricultural- and technical-grade material, with segregated handling equipment to prevent cross-contamination in the direction that matters — agricultural material into feed. Guard against caking in premixes, since a caked premix will not distribute uniformly and uniform distribution is essential when the material is being fed for a physiological effect. Keep away from strong alkalis, which release ammonia.
Notes
Palatability is the practical constraint. The salt is unpleasant to livestock and can depress intake at the levels required, so it is usually introduced gradually and blended into a total mixed ration rather than offered as a top dress. Prolonged feeding produces a metabolic acid load and is not intended as an indefinite ration component. This page describes what the material is and does; it is not veterinary advice, and dosing must be set under professional supervision.