For the first time, based on complex research, a zoo technical justification for the use of PS-۲ and PS-۴ biostimulators in the technology of calf raising in individual boxes and pavilions is given to activate the body's adaptogenesis to cold and implement the productive qualities of young stock during rearing and fattening in typical premises. Intramuscular injection of PS-۲ (polysaccharide complex of yeast cells immobilized in an agar gel by adding a benzimidazole derivative) and PS-۴ (similar to PS-۲ plus antibiotic of the cephalosporin) to
calves in a dose of ۳ ml at ۲-۳ and ۷-۹ days of life stimulates their growth and development during the raising, rearing, and fattening periods, thereby reducing the incidence of diseases. By the end of the growing, rearing, and fattening periods, the animals of the ۱st and ۲nd experimental groups outnumbered their control peers by ۷.۲ and ۸.۲ kg; ۱۱.۴ and ۱۳.۶ kg; as well as ۱۳.۸ and ۱۶.۸ kg, respectively (P<۰.۰۵-۰.۰۱). A similar pattern occurred in the nature of changes in exterior measurements and growth coefficient of animals of the compared groups. At the same time, in the
calves of the ۱st and ۲nd experimental groups, respiratory and digestive diseases were reduced by ۲.۰ and ۴.۰ times, the recovery time was decreased by ۳.۴۷ and ۵.۱۲ days, and the Mellenberg coefficient was reduced by ۳.۷ and ۱۲.۱ times, compared to the control group (P<۰.۰۵). It was found that PS-۲ and PS-۴ increased the pre-slaughter weight of the young stock by ۱۴.۶ and ۱۸.۰ kg, the weight of the hot carcass by ۱۲.۸ and ۱۵.۸ kg, and the slaughter weight by ۱۳.۷ and ۱۶.۵ kg (P<۰.۰۵-۰.۰۱). Moreover, the weight of the half-carcasses of the young stock of the experimental groups, compared to the control group, was higher by ۶.۷ and ۸.۷ kg, the yield of meat by ۵.۴ and ۶.۹ kg, and of bones by ۰.۶ and ۱.۰ kg (P<۰.۰۵-۰.۰۰۱). With an increase in the weight of half-carcasses of the experimental animals, the specific weight of the meat increased, and the bones, on the contrary, decreased. Furthermore, the yield of meat of the highest and first grades in the animals of the experimental groups increased on the background of intramuscular injection of biostimulators when using PS-۲ (by ۰.۶ and ۰.۳%; P<۰.۰۱) and PS-۴ (by ۰.۹ and ۱.۱%; P<۰.۰۱). However, the second grade decreased by ۰.۹ and ۲.۰% (P>۰.۰۵), compared to the control group.