According to Messi Biology, in the modern feed industry, magnesium oxide is a common additive primarily used to provide magnesium for animals, regulate feed pH, and even help livestock such as dairy cows alleviate heat stress during high-temperature seasons. However, many feed mills often encounter troublesome problems when using ordinary feed-grade magnesium oxide: the powder absorbs moisture and caked, mixes unevenly, or damages the gastrointestinal tract due to releasing alkalinity too quickly in the animal’s stomach. To solve these pain points, a refined processing technique known as “double-layer coating” has emerged.
First, magnesium oxide powder itself has an extremely high specific surface area and hygroscopicity. Ordinary light magnesium oxide acts like a super sponge, easily absorbing moisture in the air. Once damp, the powders stick together to form hard lumps, which not only leads to uneven feed mixing but may also clog feeding equipment. The outer layer of the double-layer coating process—fully hydrogenated palm oil—acts like a “raincoat.” It utilizes its hydrophobicity to form a dense protective film on the surface of the powder, effectively isolating moisture in the air and ensuring that the feed remains loose and free-flowing for a long period during storage.
Second, moisture prevention alone is not enough; the core lies in “sustained release.” Untreated magnesium oxide, upon entering the animal’s stomach, reacts rapidly with stomach acid, instantly releasing a large amount of alkaline substances. This “explosive” release causes a sudden surge in local pH, irritating the animal’s gastrointestinal mucosa and triggering indigestion or even stress responses. To solve this problem, the process adopts a unique “double-insurance” design: the inner layer uses acid-resistant stearic acid, and the outer layer uses hydrogenated palm oil with a suitable melting point.
This lipid film is not entirely closed; rather, it functions like a “smart gate.” When the feed enters the animal’s body, as temperature and digestive environments change, the coating layer gradually dissolves and permeates at a set rate. According to the target of this process, the alkali dissolution rate of the treated magnesium oxide within 2 hours is controlled between 36% and 39%. This means that magnesium ions and alkaline substances are released slowly and continuously, which not only plays a role in regulating acid-base balance and supplementing magnesium but also avoids impacting the animal’s gastrointestinal tract, greatly improving absorption and utilization rates.
It is worth mentioning that this coating process has extremely high requirements for temperature control. During production, workers must operate as if performing delicate surgery: first preheating the magnesium oxide to 63°C to remove water, spraying stearic acid to form the inner layer followed by cooling and solidification, and then precisely controlling the temperature between 55–58°C to spray the outer hydrogenated oil. If the temperature is slightly too high, the inner layer will melt and fail; if slightly too low, the outer oil will clump. It is precisely this strict temperature control that creates the stable performance of high-quality coated magnesium oxide.
Through physical modification, the double-layer coating technology upgrades ordinary magnesium oxide into a high-quality feed raw material with anti-caking, sustained-release, and high-flowability functions. This not only reduces waste and loss for feed mills, but more importantly, protects animal intestinal health, achieving a refined enhancement in scientific farming.