The usage period of seed-bulls, their sexual activity, the amount and quality of semen obtained from them depend both on the individual characteristics of the animal organ-ism and numerous environmental factors. The diet should contain all the necessary organic substances: easily digest-ible carbohydrates (starch and sugar), lipids, minerals and vitamins. The lack or deficiency of macro-and trace ele-ments in the diet and inadequate ratio of individual mineral elements disrupts the processes of nutrient intake into the animal body, thereby contributing to the disruption of meta-bolic processes. However, the mineral composition of plant forages depends largely on soil and climatic conditions, production and storage techniques. The average trace element deficiency in energy-balanced diets is 30-50%, and that necessitates using mineral supplements in animal diets. The nature of changes occurring in an animal body when feeding new forages, feed supplements, biological growth promoters and other products should and may be controlled through the main blood values. The research goal was to study the blood morphological composition of Black Pied seed bulls when using a mineral supplement based on maral antler press-cake. The experimental stud-ies were carried out in the breeding company AO “Plempredpriyatiye Barnaulskoye”, the Altai Region, in 2021, in the control and trial groups of comparable Black Pied seed bulls used on the farms of the Altai Region. Along with the basic diet, the seed bulls of the trial group received the mineral supplement based on maral antler press-cake; the daily dose -15.0 g per head, for 30 days with 10 days’ interval aftereach application. The supple-ment was mixed with compound feed before feeding. The mineral supplement was made at the Federal Altai Scien-tific Center of Agro-Biotechnologiesafter fermentation and autoclaving of maral antler press-cake; a significant amount of biologically active substances was found in ant-ler press-cake. The morphological status of the blood of seed bulls when using the mineral supplement made from maral antlers was characterized by a higher counts of erythrocytes, hemoglobin and leukocytes by 8.8%, 8.31% and 3.6%, higher values of hematocrit volume, mean cell hemoglobin (MCH), mean corpuscular volume (MCV), and mean cell hemoglobin concentration (MCHC) by 9.78%, 0.3%, 1.8% and 1.4%, respectively, as compared to those blood indices of the control group animals; that was indica-tive of its hematopoietic effect.

The seed bulls used for artificial insemination should be in good health, have outstanding genetic characteristics, have high sexual activity, and the biological products ob-tained from them should have high quality indices. One of the possible methods of increasing semen production is the introduction of dietary supplements into the diet. The intro-duction of new feed and biologically active supplements into the diet may cause both positive and negative changes in metabolic processes. Monitoring the biochemical status of blood allows detecting not only metabolic disorders in highly productive animals but also a lack of vitamins, mac-ro-and microelements. The research goal was to study the effect of a natural biostimulant (mineral supplement) made from maral antler press-cake on the blood biochemical indices ofBlack Pied seed bulls in the breeding company AO “Plempredpriyatiye Barnaulskoye”. Along with the basic diet, the seed bulls of the trial group received the natural biostimulant (mineral supplement) based on maral antler press-cake; the daily dose -15.0 g per head, for 30 days with 10 days’ interval after each application. The supple-ment was thoroughly mixed with compound feed before feeding. The mineral supplement is of powder form and contains a complex of vitamins, minerals, amino acids and other biologically active substances. The use of a mineral supplement increased the amount of total protein and al-bumin by 7.15% and 18.3%, respectively. The blood glu-cose level in the seed bulls of the trial group was higher by 12% and cholesterol by 17.1% than in the blood of the con-trol group animals. Cholesterol of the seed bulls may be used as a structural material or a precursor in the synthesis of sex steroid hormones. The level of total calcium, alkaline reserve at the end of the experiment increased in the seed bulls when using the mineral supplement made from maral antler press-cake in the diet by 4.8% and 8.1%, respective-ly, as compared to the control group.

The article presents the results of a study of the effect of a tissue preparation obtained from offal and slaughter reindeer by-products using a patented technology on the level and dynamics of blood T-and B-lymphocytes in young cattle of black-motley breed. Experimental studies were carried out in 2020 on the basis of "Uchkhoz Prigorodnoye" JSC in the Industrial District of Barnaul, Altai Territory on one month old heifers with an average live weight of 51,0 kg. Heifers of the experimental group (n = 10) got the tissue preparation injections once subcutaneously at a dose of 3.0 ml/head, and animals of the control group (n = 10) got saline in the same dose and multiplicity. Studies have shown that the introduction of the preparation increases the relative number of activated lymphocytes (bE-rosetting cell) by 1.5% (p≤0.05), helper-inductors (rE-rosetting cell) by 1.8% (p≤0.05), B-lymphocytes (EM-rosetting cell) by 1.7% (p≤0.05), the absolute number of activated lymphocytes (bE-rosetting cell) and B-lymphocytes (EM-rosetting cell) by 48.1% (p≤0.05) and 46.4% (p≤0.05) in comparison with the control. The relative number of killersuppressors (cE-rosetting cell) in the blood of the heifers of the experimental group decreased by 2.6% (p≤0.05), and the ratio of the ratio of helper-inductors and killer-suppressors was increased by 18.1% (p≤0.05), in comparison with animals of the intact group.

The leading role in increasing dairy cow performance is played by seed bulls; 90-96% of the herd genetic progress depends on them. This is due to the fact that for this group of animals the genetic evaluation of the individuals used is reliably carried out and the worst andmoderate animals in terms of breeding qualities are most intensively culled from reproduction. Therefore, when pure-breeding and choosing seed bulls for the herd, the information on the genotypes of milk protein alleles, in particular the kappa-casein gene (CSN3), should be taken into account. The experimental studies were carried out in the livestock breeding operation of the AO “Plempredpriyatiye Barnaulskoye”. It has been found that the prevailing genotype in the Black Pied seed bulls is the CSNAA genotype; its frequency reaches 0.578; the alternative CSN3ВB genotype is found in single ani-mals. The allele A accounts for 0.756, and B -0.245. Among the Black Pied seed bulls, no statistically significant shift in genetic equilibrium was found for any of the three genotypes of kappa-casein gene locus. The studies of the polymorphism of the kappa-casein gene in the seed bulls taking into account their line belonging have revealed that only in the Vis Back Ideal line there is a BB genotype asso-ciated with the processing properties of milk, while it lacks in the bulls of the Montwick Chieftain and Reflection Sover-ing lines. The genotype CSN3AA prevails in the seed bulls of all lines; the highest frequency occurs in the Reflection Sovering line -0.625, and the lowest in the Vis Back Ideal line -0.542. The differences in the allele frequencies be-tween the lines, apparently, are associated with the peculi-arities of the origin of the seed bulls and the direction of the selective breeding work with the Black Pied cattle.

The article presents the results of studies on the introduction of a tissue biostimulator to dry cows in order to study its effect on some biological characteristics and growth rate of calves obtained from them. Dry cows of the experimental group were injected with a tissue biostimulator subcutaneously, four times with an interval of 14 days at a dose of 22.5 ml/head, control animals -saline solution in the same dose and multiplicity. Calves of the experimental group showed an increase in the total amount of protein in the blood serum by 2.7% (P≥0.05), albumin by 1.2% (P≥0.05), γ -globulins by 1.5% (P≥0.05), albumin-globulin coefficient by 5.6% (P≥0.05) in comparison with the control. Experimental animals had a greater live weight from 2 to 6 months of age by 17.9% (P≥0.001) -23.4% (P≥0.05) in comparison with the control. An increase in average daily and absolute increase in live weight in calves of the experimental group in the 1st and 2nd month of growing by 62.9% (P≥0.05) and 64.2% (P≥0.001) was detected, respectively, a relative increase of 64 5% (P≥0.05) and 40.3% compared with the control.