Studies were conducted at the dairy complex of «Rus Ltd» (Perm Region). The effect of the use of vitamin-herb flour (VHF) from Rhaponticum carthamoides green mass in the feeding of holstinized black-and-white dairy cows was studied during the period of 12 days before calving and the first 30 days of lactation. The experiment was carried out according to the generally accepted method with the selection of analog pairs. The cows of the control group received a feeding ration consisting of feeds available at the dairy complex. For cows of the experimental groups, the composition of the concentrate part of the diet included VHF from leucea safflower in doses: the first group -4 % (0.4 kg of VHF per head per day), the second group – 10 % (1.0 kg of VHF per head per day). The experimental data of the experiment showed that VHF from leuzea as part of the concentrate part of the diet had a positive effect on the milk productivity of cows during the first 30 days of lactation, as well as on the bioconversion coefficients of protein and energy in the dairy products of cows. During the accounting period of the scientific and economic experiment (the first 30 days of lactation) from cows of the first and second experimental groups there has been obtained milk with natural fat content higher by 55.80±4.90 kg (8.04 %) (p<0.05) and by 99.20±5.80 kg (14.29 %) (p<0.05), respectively, compared to the control group. The gross yield of milk fat and protein for the reference period in cows of the first and second experimental groups was higher by 2.50±0.04 kg and 4.28±0.07 kg, by 2.54±0.16 kg and by 4.01±0.18 kg, respectively, compared with the control group. The cows of the first and second experimental groups had higher coefficients of protein bioconversion into dairy products by 2.98 % abs (p<0.05) and 3.97 % abs, respectively, compared to the control. The energy consumption for milk synthesis in the control group cows was reduced by 163.62 MJ and 349.18 MJ (p<0.05), respectively, in comparison with the cows of the first and second experimental groups, due to their lower consumption of the amount of feed mixture during the accounting period. The cows of the first and second experimental groups also had higher bioconversion coefficients of energy into milk by 2.14 % abs. and by 3.71 % abs. (p<0.05), respectively, compared to the cows of the control group. The cows of the experimental groups turned out to be more responsive to changes in the feeding diet and showed higher results according all the studied parameters.

The article presents the results of identifying the effect of feeding different doses of winter rye grain extrudate on the digestibility of diet feeds and the biochemical composition of rumen fluid and blood of replacement heifers. The research was carried out at the Sokolovo dairy complex (Perm Krai). The objects of the study were replacement heifers of Holstein blackand-white breed aged 12-15 months. The concentrate part in the diet of heifers of the experimental groups consisted from winter rye grain extrudate: in the first group by 12.5 %, in the second – by 25.0 %, in the third – by 50.0 %. As the result of the research, it was revealed that the replacement heifers of the first, second and third experimental groups showed great results compared to the heifers of the control group in the digestibility of the dry matter of the diet feed by 0.63 %, 0.99 and 1.77 % (p<0.01), respectively. The ammonia content was in the rumen fluid of the first experimental group of heifers three hours after feeding by 0.62 mg% (2.97 %) p<0.05, in the second experimental group by 1.22 mg% (4.77 %) p><0.05, in the third –> ˂ 0.05, in the second experimental group by 1.22 mg% (4.77 %) p˂0.05, in the third – by 1.70 mg% (9.42 %) p˂0.01 less, compared to the control. The level of urea in the blood of heifers of the experimental groups was lower, compared with the control, in the first ‒ by 0.34 mmol/l (by 6.65 %), in the second by 0.46 mmol/l (9.21 %) and in the third – by 0.58 mmol/l (14.90 %) p˂0.05.