The importance of breeding along the lines cattle of dairy breeds

The aspects of reasonableness in developing the line breeding strategy at the current status stage of dairy breeds and its significance as a factor for genetic variability have been reported. The value for milk production of the first-calf heifers within the line-bred pedigree Red-and-White cattle is estimated. Particular characteristics of the progeny produced from mating in the inbred and crossbred lines are recorded. The lower trait variability of traits was found with selecting within the crossbred lines than that in the inbred lines. Thus, the variables for the milk yield, the mass fraction of fat (MFF) in milk, and the mass fraction of protein (MFP) were less by 4–13% of the mean square deviation, 11,3–20,6%, and 14,3%, respectively. Livestock breed differentiation between the breeding lines was previously executed with the artificial elements of isolation systems. At present, the breeds widely distributed in the Russian Federation are usually “improved” with the use of Holsteins. Therefore, their genealogy and breeding structures depend on the foreign gene pool. Selection strategies for the improvement of milkability traits were implemented along with selection of bull sires capable of improving the conformation. In addition, certain herd bulls were used repeatadly. The variables for genetic values for milkability traits, which changed over time, were monitored. The herd milk production within the lines over a generation increased by 624–786 kg milk (P<0,001), while the MFF deacresed by 0,18–0,25% (P<0,001). Depending on the types of breeding, the differences in the milk yields and the MFF of the first-calf heifers between the lines comprised 178–444 kg (P<0,001) and +0.01%, respectively. However, a statistically significant difference between the lines was recorded only for the MFP, which comprised 0,03% (P<0,001).

Pig breeding development and analysis of the modern pork market in Russia

Pig breeding is one of the key areas for the development of livestock meat production both in Russia and in the world. According to forecasts of various agro-industrial companies and information and analytical agencies, by the end of 2020, pork production was predicted to grow similar to that in 2019, which was 5,1% (or more than 192,6 thousand tons, in slaughter weight, compared to 2018). This would represent more than a third of the total meat production in Russia, which was estimated at 11,04–11,22 million tons (as compared to 10,9 million tons in 2019). According to preliminary data from the Ministry of Agriculture of the Russian Federation (dated February 4, 2021), pork production increased "at 8.9% by 2019, which in live weight is +446 thousand tons", while the total meat production in Russia in 2020 reached 15,6 million tons, an increase of 3,1% (+472 thousand tons) more than in 2019. These indicators significantly exceed the forecasts indicated above, which is associated with the implementation of investment projects (primarily with state participation) in this direction and "expansion of export opportunities for Russian suppliers" in 2020. Despite the sanctions, coronavirus and other global challenges to the Russian economy, pork has been the "main driver" for the growth of meat production in Russia in recent years. Now our country is on the 4th line in the ranking according to the pig numbers (46.5 million heads in 2019) after China, the European Union and the United States of America. Agricultural enterprises in Russia account for 83,4% of pigs, 14,6% – on personal subsidiary plots, 2,0% – on farms. According to experts, the long-term development trend is an increase in the number of pigs in 5 years by 27,7%, in 10 years – by 36,1%, and the annual increase in pork production is planned at about 5%. Thus, in recent years, pork production has determined a positive trend in all domestic livestock farming in terms of the volume and quality of meat produced in Russia.

Estimation of the genetic activity of epinephrine hydrotartrate on the model of erythrocytes in peripheral blood in mice

The aim of the study was to evaluate the genetic activity of erythrocytes in peripheral on the model of peripheral blood erythrocytes in mice. The studies were carried out on mice (males) of the C 57B4/6 line weighing 20 g (1,5–2 months of age). For each experimental and control variant, six males were taken. The animals were kept in vivarium conditions according to international criteria for rinofix bedding, food and water ad libitum. When determining the genetic effects, the adrenergic receptor ligand was injected subcutaneously once. After 8 hours, a mutation inducer, an alkylating drug, cyclophosphamide, was injected intraperitoneally at a dose of 30 mg/kg. Before the end of the experiment in 2,5 hour, mice were injected intraperitoneally with 2.5 mg/kg of colchicine. 24 hours after injection, the animals were euthanized by delongation. The number of erythrocytes with micronuclei was counted from 2000 analyzed cells. The greatest antimutagenic effect (87,5%) of epinephrine hydrotartrate, a stimulator of α- and β-adrenergic receptors, was found at doses of 5 and 0,5 mg/kg.

On the adaptive capabilities of beavers (Castor L., 1758)

Based on observations of beavers in anthropogenic landscapes, the study of methods of their maintenance and feeding in the zoo assumptions are made about the broad ecological plasticity of the species. This is achieved by both morphophysiological adaptations and behavioral adaptations, which are associated with the processes of synanthropization and domestication. This is also associated with the processes of rapid restoration of the number of beavers and their range in places of former extermination. The river beaver is a promising object of zooculture, including breeding in artificial conditions.

Assessment of some hematological indicators of breeding falls of the zabaikalsky breed

The results of studying the morphological and biochemical parameters of the blood of young horses of the Trans-Baikal breed, depending on the zone of their breeding and age, are presented. The study of hematological parameters is one of the most important diagnostic methods for assessing the physiological and clinical state of animals. The research material was stallions at the age of 12, 18, 24 and 36 months. It was found that hematological parameters were within physiological norms, while in stallions of the forest-steppe zone they were higher in comparison with analogs of the steppe zone. With age, there is a decrease in the estimated hematological parameters in the experimental stallions.

Population characteristics of daughters of domestic and foreign breeding bulls

The use of foreign-bred bulls leads to changes in the genetic structure of the black-and-white breed population, which affects the level of population characteristics. The study was conducted to study the comparative variability and heritability of productive and reproductive characteristics of daughters of sires of domestic and foreign selection in pedigree livestock 10 250 cows 1st calving modern population of black-motley breed of the Vologda region. The superiority of the offspring of foreign bulls in the average indicators of all the studied traits was established with confidence (P<0,001). There were no significant differences in the level of variability of the characteristics of the descendants of domestic and foreign bulls. According to productive traits, the greatest variability of indicators was established for milk yield for 305 days of the 1st lactation Cv = 17,3 – 17,7%, therefore, selection on this trait will be more effective. The greatest share of the influence of bullsfathers, both domestic and foreign selection, in the total sum of all factors determining the value of traits in the population of the black-and-white breed, is determined by the milk yield of daughters η2 = 0,22 – 0,24, the age of the 1st fruitful insemination and the first calving η2 = 0,24 – 0,25. In further breeding work with the breed, it is necessary to obtain and use domestic producers that exceed the breeding value of foreign bulls.

Prospects for the use of highly effective and safe stimulants of embryogenesis in poultry farming

To increase the embryonic and postembryonic viability of poultry, along with selection work, optimization of the microclimate parameters of poultry houses and rations, it is also advisable to develop resource-saving and environmentally friendly methods of using biologically active substances. It was shown that the treatment of eggs with a composition of solutions of natural metabolites (colamine, succinic acid and Ribav) in optimal concentrations stopped and prevented the negative effects of stress. Positive biochemical and morphological changes were observed in the development of chick embryos. An increase in chick withdrawal, a decrease in all incubation waste, an increase in the activity of antioxidant defense enzymes, and a decrease in the content of malondialdehyde in the blood serum of chickens were found.

Determination of albumin content in blood serum based on the results of dynamic surface tension

The blood test allows you to give an objective assessment of the state of health of animals and timely identify changes occurring in the body. To assess the content of albumins in the blood serum, the method of measuring the dynamic surface tension on the VRA-1P device, which works according to the method of maximum pressure in the bubble, was used. Based on the results of the measurements, a mathematical model was proposed, and using the regression analysis method, formulas for determining the concentration of albumins were developed, which showed good convergence with other measurement methods.

Effects of protected vegetable fats on rumen metabolism and productivity dairy cows

In a scientific economic experiment conducted in the experimental farm «Klenovo-Chegodaevo» (Moscow) on three groups of Holsteinized black-and-white cows with a milk yield of 7000 kg of milk per lactation, 10 heads in each, it was found that the inclusion in the diet of cows of the experimental groups tested protected fats (hydrogenated and fractionated) in the amount of 300 g per head per day, contributed to the tendency for more intensive metabolic processes in the rumen due to a slight increase in the concentration of volatile fatty acids by 5,6–7,4% and an increase in the mass of microorganisms in the contents of the rumen by 5,4–14,4% (P≥0,05). At the same time, an increase in the concentration of metabolic energy in the dry matter of the cows ration from 10,7 to 11,0 MJ / kg in the period from 21 to 120 days of lactation, due to the inclusion of protected fats in the diet of cows from the experimental groups, contributed to an increase in milk yield 4% fat content for 100 days of the experiment by 9,7% and 11,0% (P≤0,05), compared with the control, as well as the production of milk fat and protein, respectively by 9,6–11,0% (P≤0,05 in the second case) and 7,4–8,3%, feed costs expressed in ME decreased by 4,9–5,2%.

Determination of the minimum suppressive concentration of photosensitizers of the second generation in relation to sanitaryindicative microorganisms

In the studies described in the article, the presence of antimicrobial activity in photosensitizers in experiments on bacterial cultures was confirmed. In the experiments, photosensitizers of the second generation were used: «Photoditazine», the active substance of which is dimeglumin chloride E6, and «Dimegin», which includes a derivative of protoporphyrin IX-2,4-di(1-methoxyethyl)- deuteroporphyrin IX disodium salt. In the described research work, the minimum concentrations of the studied drugs were determined by the method of sequential tenfold dilutions to obtain a bactericidal effect on strains of sanitary-indicative microorganisms Enterococcus faecalis, Staphylococcus aureus, Salmonella enteritidis.