Relevance . Currently improving of the quality of agricultural products is a point of constant attention. The nutritional value and commercial quality of milk depend on its chemical composition and properties, which are influenced by numerous factors, the most important among them is animal feeding. The prospects of using feed additives based on natural agro-minerals in animal husbandry are increasing. These include such silicon-containing sorbents as zeolite, diatomite, bentonite, tripoli, and montmorillonite. Material and methods . Production tests lasting 100 days were carried out in the OOO "Agrofirma "Tetyushskoe"" of the Ulyanovsk region. The object of the study was Black-and-White cows. We created 4 groups using the principle of analogy, each with 50 cows. The feeding is carried out with household rations. The difference was as follows: the 1st group received only a household ration (OR); the 2nd group received OR and an additive of modified zeolite enriched with an amino acid complex of plant origin (the drug «Aminobiol»); the 3rd group received OR and an additive of modified diatomite enriched with the same amino acids. Cows of the 4th group received OR and an additive of modified diatomite without amino acids. Results . Feeding modified silicon-containing additives enriched with amino acids has a positive effect on the fatty acid composition of cow's milk, increases the concentration of caprinic (C10:0), lauric (C12:0), myristinic (C14:0), palmitic (C16:0) and heptadecoic (C17:0) fatty acids, milk productivity and improves the qualitative composition of milk.