The research was devoted to studying the influence of the Tamir biological product in the loose deep-litter keeping of the cattle on the indicators of rearing stock live weight, average daily weight gain, and withdrawal of replacement heifers, cows, and first-calf heifers due to the limb diseases. The study was performed at the stud farm for breeding the black-motley breed of the Integrated Agricultural Production Company (collective farm) Udmurtia in the Vavozhsky district of the Udmurtian Republic in the period from 2013 to October 2018. The report on animals culling from the main herd, and reports on animals weighing have shown that in 2013–2014, before the use of the biological product, the number of heifers withdrawn from the herd at the age of 10–12 months was 12 (in 2013), or 1.4%, and 13 (in 2014), or 1.4%; at the age from 12 to 18 months – nine (2013), or 1.1%, and 12 (2014), or 1.3%; at the age of 18 months and older – three (2013), or 0.6%, and eight (2014), or 0.5% of the total number in the age groups of the animals. In 2015–2017, i.e., after the use of the biological product, the number of heifers withdrawn from the herd at the age of 10–12 months was nine (1.1%), six (0.6%), and seven (0.6%); at the age of 12–18 months – seven (0.8%), five (0.5%), and three (0.3%); at age 18 months and older – two (0.2%), two (0.2%), and one (0.01%) of the total number in the age groups of the animals. Withdrawal of rearing stock due to limbs diseases was also analyzed. While before the use of the biological product, in 2013–2014, 26 animals, or 3.0% (2013) and 33 animals, or 3.5% (in 2014) had been withdrawn from the herd, after the use of the biological products in 2015–2017, this figure dropped to 18 animals, or 2.2% in 2015, 13 animals, or 1.2% in 2016, and 11 animals, or 1.0% in 2017. Thus, the percentage of the withdrawn heifers after the use of the biological product decreased from 3.0–3.5% to 1.0–2.2%, or almost three times. Analysis of the average daily weight gain by young animals in all age periods has shown that after the use of the biological product, the average daily weight gain increased, compared to the period before its use, which confirms the growth of this indicator. The live weight of the replacement heifers at first insemination before the use of the product amounted to 382–381 kg, and in 2015–2017, after the use of the product, it amounted to 385–388–390 kg, which also indicated the positive effect of the product on the growth. The percentage of the cows withdrawn from the main herd after the use of the biological product reduced from 10.3–15.4% to 5.8–6.1%, i.e., by 4.5–9.3%; of first-calf heifers – from 11.0–17.1% to 3.4–7.1%, i.e., by 7.6–10.0%, by the years of withdrawal, respectively. After processing the manure with the Tamir biological product, the fraction of manure became solid (crumbly) and lost the smell. Thus, the use of the Tamir biological product in the technology of loose keeping of cattle on deep litter increased the daily weight gain in heifers and their live weight at first insemination, and reduced the share of low-productive cows and first-calf heifers, as well as the incidence rate of limb diseases.