Molochnokhozyaistvenny Vestnik

The article is devoted to the development of a new fermented milk drink with increased nutritional value, which is achieved through the use of crushed wheat bran and maple syrup in the recipe. The characteristics of the fillers used are presented, the doses of their application are justified, the calculations of the food and energy value of the product are carried out. It was found that product samples containing 5 % or more wheat bran are functional in terms of the content of the mineral substance manganese in them: when using a single portion of a product equal to 100 g containing 5 % wheat bran, the daily need for manganese is satisfied by 45 %. In addition, the fermented milk product with wheat bran contains 3.9 g of dietary fiber per 100 g and is their source.

Dynamic changes in the dairy cattle industry in the North-Western Federal District and the Vologda Region require their monitoring and studying to determine promising development trends. The article presents gross milk production analysis, the dynamics of livestock and economically useful characteristics of dairy cattle in the North-Western Federal District and the Vologda Region taking into account the statistical collected works data published by the Food and Agriculture Organization of the United Nations (FAO) in 2020, the Federal State Statistics Service of the Russian Federation, and the yearbooks for 2011-2020 on breeding dairy cattle in the Russian Federation. The number of dairy cattle has been stabilized since 2017 in the district, and since 2013 in the region. A period of cow use has been reduced in 2019 compared to 2011 by 0.32 calving in the Northwestern Federal District and by 0.15 calving in the Vologda region. There is a growth tendency in milk productivity: the milk yield of cows has increased by 2304 kg in the Northwestern Federal District, and by 2470 kg of milk in the Vologda Region in 2010-2019. The authors describe the breeding base of the district and the region by the specific weight of the breeding stock, the number of breeding farms, the level of productivity and the sales volume of breeding animals. The article gives a brief description of the breed structure of dairy cattle in the district and the region and analyzes the genetic potential of breeding bulls used in the breeding stock of dairy breeds of the Vologda region. The authors also determine the main directions in selection and breeding, which are aimed at dairy breed improvement in the region.

In the experiments the mineral composition of narrow-leaved fireweed was studied in different phases of its growing season in the conditions of the NorthWestern region of Russia in the Vologda region. It was experimentally established that narrow-leaved fireweed is a promising forage plant in the North-Western zone of Russia. It can meet the needs of lactating cows in macro-and microelements, except sodium, zinc, copper and cobalt. Taking into account the fact that there is a lack of phosphorus in the plant feeds of the Vologda region, using narrow-leaved fireweed for feed will to some extent compensate for its lack in the dairy cattle diet. The dynamics of the mineral content in the plants of narrow-leaved fireweed in dry matter is: the growth of the stem – macroelements; calcium – 7.53 g/kg, phosphorus – 7.36, magnesium –3.42, sodium – 0.17, potassium – 20.8 g/kg. Microelements: zinc – 47.5 mg/kg, copper – 5.39, cobalt – 0.25, iron – 129 mg/kg of dry matter of the plant. It is established that the chemical composition of fireweed changes in the process of development and growth. Therefore, when feeding the green mass to cattle, as well as when harvesting raw materials from it for the production of various feeds (hay, haylage, silage, grass meal), it is necessary to take into account the optimal content of macro- and microelements in its plants, which will allow to better balance the rations of cattle in mineral nutrition and get higher productivity from animals.

Studies were conducted to study the variability and correlation of indicators of dairy productivity of cattle in the conditions of breeding enterprises of the Omsk region, as well as the optimal size of the breeding group was determined on the basis of the Pareto diagram. It was found that the coefficient of variation of milk yield in cows of the red steppe breed was 23.4 %, which is 4.3% more than in cows of the black-and-white breed. To form breeding groups in breeding farms in the region, they must have a milk yield of at least 7000 kg of milk. Among the available livestock, the specific weight of animals of the desired quality is 6 % for the red steppe and 6.6% for the black-and-white breeds.

The paper presents an assessment of the phagocytic ability of blood cells of Nile tilapia Oreochromis niloticus L. under the hormonal induction of stress with range of duration. It has been revealed that Staphylococcus aureus is phagocytosed by leukocytes, platelets, and erythrocytes of tilapia blood in direct smears. The phagocytic capacity of the cells has been quantified. It has been found that long-term exposure to stress has an immunosuppressive effect on the phagocytic activity of leukocytes and an immunostimulating effect on the phagocytic activity of erythrocytes (60-minute incubation) by the end of the experiment in comparison with other groups. Short-term exposure to stress increases the activity of leukocytes and decreases the activity of erythrocytes (60- minute incubation) for 7 days after exposure.