A full-fledged yearling of young cattle should be based on scientifically based standards, guaranteeing their genetic productivity potential, rational use of feed resources, and proper payment for feed with meat products. The current situation regarding the rationing of yearling livestock in global and domestic, both scientific and production practices, has fundamentally changed, which requires a significant revision of traditional provisions on the organization of rationed yearling and feeding of farm animals. At the same time, the conceptual requirements for the organization of standardized feeding of young livestock should be based on the general world experience of the need for energy, nutrients, and biologically active substances of animals, taking into account the age period of the growing season, with an emphasis on the quality and biosafety of products. In the intensive production of meat products, to ensure high productivity, it is only possible to do so by using feed products of natural substance, which should include additives with a phytobiological effect. One of these consists of the feed supplement “PROGALplv,” which contains the probiotic component maltodenstrin and fructooligosaccharides and belongs to the probiotic supplement for ruminants. Based on the research, optimizing the standardized feeding of fattening young animals on diets with different energy levels and using the biological feed additive “PROGALplv” at the rate of 6, 10, and 15 g/head was set a day. The research was conducted on Simmental bulls in the conditions of the farm “Pchany-Denkovych” of the Stryi district of the Lviv region. It was established that using “PROGALplv” bio-additives in the ration against the background of different energy nutrition contributed to an increase in the intensity of physiologically helpful microflora of the rumen, which had a stimulating effect in the processes of additional assimilation of nutrients. A positive result was obtained regarding the average daily gains and quality indicators of meat products and the economic efficiency of the final fattening period. Thus, based on the results of our research, it is possible to recommend the introduction of an increased level of energy nutrition of 110 % of the explicit norms into the intensive technology of livestock removal at the expense of an entirely rational feed mixture with the inclusion of the probiotic feed additive “PROGALplv” at the rate of 10 g/head per day. The optimal introduction dose to compound feed compliance is 10 g/head. The maximum amount can be no more than 15 g/h. daily. No adverse side effects of “PROGALplv” bio-additives on the general functional condition of Bugai residents were found.