Streptococcus suis is one of the most common infectious agents in countries with highly developed pig breeding. The disease caused by this pathogen is characterized by septicemia and sudden death, as well as acute meningitis, polyserositis, pneumonia, polyarthritis and serous-purulent dermatitis. The first data on infection S.suis were published in the Netherlands (Jansen & Van Dorssen, 1951) and England (Field et al., 1954). Since that time, streptococcosis has received worldwide distribution, and the issue of combating it remains relevant now. In streptococcal infections, the number of carrier pigs reaches 100%. Cases of the disease vary depending on the growing period and usually do not exceed 5%. There are three clinical forms of the disease - acute, subacute and chronic. The acute form occurs in the form of septicemia and by sudden death, subacute is most often manifested in the form of meningitis. The control is based on the prevention of the predisposing factors, antibiotic therapy and the elimination of the pathogen in the environment. The veterinary control scheme for streptococcosis allows to achieve 95% of the therapeutic effect and is a key means of protecting the enterprise against economic losses associated with S.suis

Lots of studies show that there is an important correlation between the activity of the endocrine intestine apparatus and the intensity of secretion of the thyroid, sex, dairy and other glands. The purpose of the research was to study the effect of biological products on hematological, immunological parameters and the natural resistance of pigs of different age and sex groups. The hematological parameters of pigs fed with duodenum extract and probiotics were studied. In most hematological parameters animals receiving "Bifidumbacterin" in combination with duodenum extract had an advantage in all age periods. Thus, the use of "Bifidumbakterin" with duodenum extract led to an increase in all hematological parameters: the number of red blood cells and hemoglobin, the content of leukocytes and total protein in blood, the absolute number of lymphocytes.

The effect of smectite tripoli in the grain feed mixture in summer and winter periods was studied via two experiments on the black and motley breed calves in the SEC Agricompany "Culture" in the Bryansk region. Three groups (each of 10 livestock units) were selected for the trial. The main feed was whole milk. The composition of grain feed in summer included smepitny tripoli in the amount of 15 and 20 g/day per head. In winter, 30 and 40 g of natural mineral additive were included in the grain feed mixture. The results show that in the summer period in the experimental and control groups live weight of calves and average daily gains were almost equal. However, in winter, in the second experimental group that was fed 30 g of natural mineral additive smectite tripoli the average daily gain in calves was more by 5.9%, which allows to conclude that 30 g of smectite tripoli in the grain feed in the winter period is the optimal dose for calves. The analysis of economic efficiency showed that feeding smectite tripoli in the grain feed mixture in the milk period significantly influenced the profit in the second experimental group, where it was 30.6% more than in the control group. In the group that received 40 g of smectite tripoli in the grain feed mixture the profits were less by 6.1%.

In sorghum hybrids selection the identification of the source material combining high yield and adaptation to abiotic and biotic conditions of cultivation is actual. The methods for determining the adaptive capacity of CMS-lines (coefficient linear regression and variation) make it possible to reveal their response to growing seasons differing in climatic conditions. Observation of grain sorghum plants was carried out in 2009-2018 on the experimental field "Rossorgo". Environmental factors have less impact on the signs: period of "germination-flowering", plant height, length inflorescence, length and width of the largest leaf (V = 5.0-19.8%). The wide variability of characters (V = 13.3-44.3%) was revealed by the intensity of the initial plant growth, the width of the inflorescence, the area of leaf and grain yield. As a result of the regression analysis, lines that are distinguished by their plasticity and phenotypic stability according to a complex of selection traits were found. A2 KVV 114 is highly plastic in terms of its economic characteristics. The CMS lines M35-1A Pischevoe 614 and 9E Pischevoe 614 differ in phenotypic stability in yield (b_i = 1.01-1.07) and plasticity in the length and width of the inflorescence (b_i = 1,40-2.49). Sterile lines A3, A4 and 9E Zheltozernoe 10 are capable of forming a grain harvest in more droughty growing seasons (b_i = 0.80-0.83) and have phenotypic stability of the characteristics: the "germination-flowering” period, the height of plants 30 days after germination and when ripe, the area of the largest sheet. According to the results obtained, it is recommended to include a working collection of maternal forms in the program of crosses in order to obtain productive hybrids that are adapted to the conditions of the Lower Volga region.

The article presents the results of field experiments carried out in 2016-2018 in the North-Eastern zone of the Rostov region on dark chestnut soils. The aim of the research was to study the effect of mineral fertilizers and bacterial preparations on the yield and quality of safflower seeds. The object of the study was the variety of safflower Zavolzhsky-1, predecessor was winter wheat. Ammonium nitrate and ammophos in doses of N₂₄P₅₂ and N₄₈P₅₂ were used as mineral fertilizers with application at sowing and under presowing cultivation. In a field experiment we studied the variants of joint application of mineral fertilizers and pre-sowing seed treatment of bacterial preparations (Miserin, Flavobacterium, KL-10 produced by research center of Pushkin). Control was an option without the use of mineral fertilizers and bacterial preparations. The research methodology was standard for studying the effect of fertilizers. The average yield of safflower seeds in field experiments was 1.03-1.22 t/ha, oil content of seeds - 35.9-36.3%, oil collection from 1 ha - 337-398 kg. It was established the optimal dose of mineral fertilizers, providing the greatest crop yield, was the application for pre-sowing cultivation N₄₈P₅₂. In comparison with the control on this variant, the maximum increase in the yield of safflower seeds in the experiment was obtained - 0.19 t/ha or 18.4%. It was revealed that the best bacterial preparation is Flavobacterium. The increase in yield compared with the option without the use of fertilizers was 0.14 t/ha or 13.6%. The combination of mineral fertilizers and biopreparations is most effective on the variant using the preparation KL-10, where the yield compared to the control variant increased by 0.11 t/ha or 10.7%.