Goal. To determine the productive and slaughtering qualities of cattle and the chemical composition of muscle tissue and liver for the use of various high-protein fodder — narrow-leaved lupine and fodder beans — as part of fodder grain mixtures. Methods. 2 groups of experimental animals were formed: 1st group (control) was fed with grain mixture No. 1 with narrow-leaved lupine (alkaloid-free); II group (experimental) received grain mixture No. 2 with fodder beans. The live weight of young cattle was determined by individual weighing before morning feeding; the payment of feed by live weight gain was determined by the calculation method; the slaughter quality was determined by the technology adopted at meat processing enterprises; the chemical composition was determined by generally accepted methods. Results. Optimizing the protein nutrition of fattening bulls thanks to various high-protein forages has a positive effect on performance indicators (822–870 g) and feed conversion (109.1–114.1 MJ), does not have a negative effect on slaughter qualities and the chemical composition of the longest back muscle and liver. Conclusions. Replacing 30% (by mass) of lupine in the composition of the grain mixture with the appropriate amount of fodder beans for young cattle on fattening insignificantly reduces the average daily gains in live weight (by 5.5%), and increases the expenditure of exchangeable energy per unit of gain (by 4.6%). No significant intergroup differences were found in terms of slaughter performance of young bulls. A comparative analysis of the chemical composition of the longest back muscle of cattle shows that in the muscle tissue of animals of the II (experimental) group, the concentration of dry matter, protein, fat, and ash was lower by 0.96%, 0.64, 0.31 and 0.01% abs., respectively, than in the I (control) group.