A method for improving the reproductive performance of first-calf heifers using a complex mineraland vitamin feed additive is presented to the production. The animals of the control group were fed according to the main diet accepted in the farm and mineral matters. The animals from group I were fed the main ration with 120 g of the complex mineraland vitamin feed additiv per head according to recipe No.1. The animals from group II received the main ration with 120 g of the feed additive per head according to recipe No.2. The cow mating index of the first heifers of the control group is 2.1, which is0.48 and 0.60 times higher than in groups I and II. The highest rate of fecundation showed the cows of the experimental group II. It made up 63%, 7% higher than the experimental group I(56 %) and 18% higher than the control group (45 %). After the second fecundation, the conception rate in group II was 37%, which is 18% higher than in the control group and 7% higher than in animalsof group I. The calf crop in all groups was 100%.

В условиях племрепродуктора в Республике Башкортостан были проведены опыты по изучению влияния селеносодержащего препарата ДАФС-25 на рост и мясную продуктивность бычков симментальской породы. В опытной группе животные характеризовались более высокой интенсивностью обменных процессов. Они превосходили по содержаниюбелка в крови бычковконтрольнойгруппы, где разницасоставила в 3 мес 0,9 г/л (1,17), в 6 мес 1,41 г/л (1,84), в 12 мес 1,54 г/л (1,99), в 18 мес 1,18 г/л (1,51). Установлено, что у животных, получавших добавку, активность ферментов АСТ и АЛТ была выше, чем в контроле, соответственно, на 0,100,22 ед. (2,7013,74), что положительно отразилось на интенсивности формирования мясной продуктивности. Лучшей энергией роста в течение опыта обладали бычки опытной группы, они имели преимущество по живой массе к концу опыта 23,7 кг (7,4). Бычки опытной группы превосходили аналогов из контроля по живой массе в возрасте 3, 6, 9,12, 15 месна 2,2 кг (2,56), 6,1 (4,25), 11,9 (5,74), 15,2 (5,42), 17,2 кг (5,13). Результаты контрольного убоя свидетельствовали, что скармливание ДАФС-25 бычкам опытной группы способствовало интенсивному увеличению живой массы и мясной продуктивности. Масса парной туши у бычков 18-месячного возраста опытной группы была на 14,28 кг (6,96) выше, чем в контроле внутреннего жира на 1,95 кг (21,33), убойной массы на 16,23 кг (7,57). У животных опытной группы убойный выход был выше на 1,05, по сравнению с бычками контрольной группы. У бычков, получавших подкормку, масса мякоти была больше на 20,31 кг, что составляет 13,05 (Р0,001). Туши животных опытной группы характеризовались лучшим соотношением в них мяса, жира и костей. Мякоти на 1 кг костей приходилось 4,56 кг, или на 0,23 кг (5,31) больше, чем в контроле.Research directed at studying the influence of selenium-based feed additive, DAFS-25, on the growth and meat productivity in calf bulls of Simmental breed was carried out under the conditions of a pedigree breeding unit located in the Republic of Bashkortostan. The animals included in the test group was characterized by increased intensity of metabolic processes. The level of blood protein of animals from this group exceeded the level of blood protein of animals from control group. The differences at the age of 3 months amounted to 0.9 g/L (1.17), 6 months 1.41 g/L (1.84), 12 months 1.54 g/L (1.99), 18 months 1.18 g/L (1.51). It was found that the activity of AST and ALT enzymes in animals that received the additive was higher by 0.10-0.22 u (2.70-13.74), respectively, than that in animals included in control group, which positively influenced the intensity of meat productivity formation. Calf bulls from the test group showed the best growth energy during the experiment. Their live weight advantage by the end of the experiment amounted to 23.7 kg (7.4). Test group calf bulls were superior to the analogues belonging to control group by live weight: by 2.2 kg (2.56), 6.1 (4.25), 11.9 (5.74), 15.2 (5.42), and 17.2 kg (5.13) at the age of 3, 6, 9, 12, and 15 months. The results of control slaughter showed that feeding DAFS-25 to calf bulls belonging to test group facilitated intensive growth of live weight and meat productivity. Hot carcass weight of 18-month-old calf bulls belonging to test group by 14.28 kg (6.96) exceeded the result of control group test group animals also exceeded those from control group by the following parameters: internal fat by 1.95 kg (21.33), slaughter-weight by 16.23 kg (7.57). Slaughter yield of test group animals was higher by 1.05 compared to calf bulls attributed to control group. Flesh weight of calf bulls who received the additive was higher was 20.31 kg more, which amounts to 13.05 (P0.001). Carcasses of test group animals were characterized by better ratio of meat, fat, and bones. There was 4.56 kg of flesh per 1 kg of bones, or 0.23 kg (5.31) more than in control group.

In a scientific and economic experiment lasting 90 days on 4 groups of black-and-white calves, formed by the method of analogs, the effect of a complex mineral-vitamin feed supplement (CMVFS ) on the nutrient digestibility of feed in the Republic of Bashkortostan was studied. Animals of the control group received the basic diet (BD) and mineral feeds (chalk, salt, premix); I, II and III experimental groups — BD + CMVFS according to recipe No. 1, No. 2 and No. 3 respectively. A distinctive feature of the recipes is the ratio of natural zeolite and sapropel in 1 kg of the supplement. It was found that the content of calcium, phosphorus, magnesium, sulfur, manganese, copper, zinc and cobalt in the green mass, as well as in the feed harvested from it, does not meet the needs of young animals. Significantly high digestibility of dry and organic matter relative to the control was observed in animals of group III by 3.84% (R<0.05) and 2.78% (R<0.05); crude protein — by 3.21 and 3.96% — in young animals of groups II and III (R<0.05); crude fat — by 2.83% (R<0.05) in group I, by 4.01% (R<0.05) in group II and by 5.05% (P<0.01) in group III; nitrogen-free extractive substances — by 3.24% (R<0.05) in II and by 3.67% (R<0.05) in III experimental groups. The balance of nitrogen and minerals in all experimental groups was positive. The digested and deposited nitrogen in the body corresponds to the obtained average daily live weight gain of calves. In order to balance the diets of calves in terms of macro- and microelements, we recommend vitamins to introduce CMVFS according to the recipe No. 3 into the mixture of grains at the rate of 35 g per 1 head per day.

The feasibility of using the complex mineral and vitamin feed additive “Nadezhda” in the rations of lactating first-calf heifers of Black-and-White breed has been examined in the article. It has been established that feed contain a low content of elements such as calcium, phosphorus, magnesium, sulfur, manganese, copper, zinc and cobalt. The ratio of nutrients and minerals, the degree of their availability for assimilation by the body does not provide their need. The use of the complex mineral and vitamin feed additive contributed to an increase in the milk productivity of first-calf heifers and the quality of milk, feed consumption per unit of production. All tested recipes of the complex mineral and vitamin feed additive, which have different versions of macro-, microelements and vitamins in their composition had a positive effect on the metabolic processes in the body of animals. For the production of 1 kg of milk in the experimental groups of cows less metabolic energy was spent by 5,09 (P < 0,05) and 8,06 % (P < 0,05), respectively, raw protein by 5,19 and 8,19 % (P < 0,05), digestible protein by 5,12 (P < 0,05) and 8,15 % (P < 0,05) compared with the animals of the control group. At the same time from the cows of the 1st experimental group have been received more milk by 151,6 kg in the amount of 2489 rubles, from the 2nd experimental group by 250,6 kg of milk in the amount of 4248,0 rubles. The prime cost of production of 1 kg of milk in cows of the 1st experimental group in comparison with the animals of the control group decreased by 0,72 rubles, and the 2nd experimental group by 1,21 rubles. The level of profitability of milk production in cows have been fed with additive recipe No. 1, in comparison with the animals of the control group increased by 3,71 abs.%, recipe No. 2 by 9,91 abs.%.

The modern agricultural market offers a wide range of products designed for a highly effective and most importantly safe increase in growth indicators, the level of development and the degree of productivity of domestic animals. The leading role in achieving the highest quality result is played by a competent choice of feed additives. The purpose of the research was to study the use of a feed additive based on biologically active substances (BAS) in the fattening of steers. The effect of the feed additive based on a natural, balanced, natural complex of biologically active substances such as vitamins B, C, PP, tryptophan (with oral administration bioavailability reaches 90 %), antioxidants, essential and free amino acids, enzymes and trace element salts on the growth and development of young cattle of Black-and-White breed has been studied. The steers of the control group received the main diet, and the animals of the experimental group in addition to the main diet received the feed additive consisting of vitamins, amino acids, antioxidants, enzymes and trace element salts. It has been found by the studies that the use of the test feed additive based on BAS provides an improvement in the digestibility and assimilation of nutrients in the diet, which contributed to the increase in the average daily live weight gain in the experimental group by 263 g or 25 %, the decrease in feed consumption for 1 kg of gain and the improvement in blood biochemical parameters, such as inorganic phosphorus, AST, ALT, alkaline phosphatase within physiological norms. In order to balance the diets of 9-monthold steers by biologically active substances and improve the physiological and biochemical status, the digestibility of nutrients that contribute to the increase in the average daily weight gain, it is recommended to use the feed additive based on BAS with drinking water.