The aim of this study was to analyze the nutritional value of feed mixtures and premixes produced in Southeastern Kazakhstan by selected feed manufacturers for dairy farms. The feed mixtures produced by the analyzed feed mills differed significantly (p ≤ 0.01 and p ≤ 0.05) in terms of their basic nutrient content. The amino acid, mineral, and vitamin composition of the feed mixtures was neither monitored nor balanced, except in the Good-Zhen feed mill, as the facilities did not produce mineral-vitamin premixes. For research purposes, the Kormovik and Vet Effect feed mills developed premixes for lactating cows, dry cows, and young cattle aged 6–12 months. The premixes contained high levels of minerals, including Ca, P, Mg, Na, Cl, Cu, Zn, Mn, Co, Se, and I, as well as vitamins A, D, and E. For high-yielding cows from the OST group and for cows in the first dry period (Period I), an antioxidant was added at levels of 177 mg/kg and 95 mg/kg, respectively. Additionally, for low-yielding cows and cows in the second dry period (Period II), supplementary vitamins were included: K, B1, B2, B4, B5, B6, B9, B12, and PP. The experimental premixes used in cattle feeding on the JSC AIC Adal farm allowed the maintenance of milk yield in cows kept there at the level of 8 000 kg of milk. The research shows that including premix in cattle feed rations allows them to be balanced in terms of nutritional value, minerals and vitamins, which ultimately allows for better use of the animals' genetic potential.