The animal’s blood is the most complicated and important biological liquid for veterinary medicine. In addition to standard methods that are always in use, recent technologies such as dynamic tensiometry (DT) of blood serum and PCR analysis of particular markers are in progress. The standard and modern biochemical tests are commonly used for general screening and, finally, complete diagnosis of animal health. Interpretation of major biochemical parameters is similar across animal species, but there are a few peculiarities in each case, especially well-known for cattle. The following directions are discussed here: hematological indicators; “total protein” and its fractions; some enzymes; major low-molecular metabolites (glucose, lipids, bilirubin, etc.); cations and anions. As example, the numerous correlations between DT data and biochemical parameters of cattle serum have been obtained and discussed. Changes in the cell-free nucleic acids (cfDNA) circulating in the blood have been studied and analyzed in a variety of conditions; for example, pregnancy, infectious and chronic diseases, and cancer. CfDNA can easily be detected using standard molecular biological techniques like DNA amplification and next-generation sequencing. The application of digital PCR even allows exact quantification of copy number variations which are for example important in prenatal diagnosis of chromosomal aberrations.

Due to the intensive development of technologies for obtaining protein, energy feed and biologically active supplements from insects, the feasibility and effectiveness of introducing these products into the rations of farm animals require further study. This research aims to study the possibility and effects of feeding dairy cows fat from the larvae of the black soldier fly (BSFLF). The composition and properties of the BSFLF have been studied. The research of the fatty acid composition of BSFLF showed a high content of saturated fatty acids, including 58.9% lauric acid. The experiment was performed on black-and-white cows at the beginning of lactation (control, D0 (n = 12) vs. experimental D10 (n = 12) and D100 (n = 12) groups, 10 and 100 g/head/day BSFLF, respectively. There was no negative effect of BSFLF feeding on the process of feed digestion. The pH of the rumen content decreased (6.80 ± 0.07 & 6.85 ± 0.09 vs. 7.16 ± 0.06, p < 0.05), with an increase in the number of infusoria (0.27 ± 0.03&0.37 ± 0.09 vs. 0.18 ± 0.03 g/100 mL, p = 0.16); there was an increase in the concentration of VFA in the rumen content of animals of the experimental groups by 2.1 (p < 0.05) and 3.81 (p < 0.01) (8.66 ± 0.46 & 10.37 ± 0.42 vs. 6.56 ± 0.29) mmol/100 mL. The average daily milk yield of Group D10 cows over the experimental period (d17–d177) was slightly higher than the control (by 4.9%, p = 0.24 vs. Group D0). At the same time, Group D100 cows showed a significant increase in natural-fat milk compared to controls (by 8.0%, p < 0.05 vs. Group D0) over the same experiment period. Analysis of the fatty acid composition of the milk of the experimental animals showed some changes in the fatty acid composition of milk under the influence of BSFLF feeding; these changes were especially noticeable in Group D10. Thus, it was found that feeding dairy cows BSFLF at different dosages leads to better indicators of pre-gastric digestion and productivity.

The effect of activated charcoal as a feed additive was assessed in the experiment with Romanov sheep and Romanov sheep breed with argali. Charcoal sorbent is the original preparation produced in “Khiminvest” Science and Technology Center. Activated charcoal supplement was added to the basic diet of experimental animals in an amount of 1 g per 10 kg of live weight. The preparation showed positive effect on the palatability of the feed and ruminal digestion processes, as well as contributed to an increase in dry matter concentration of microorganisms and amylase activity. Experimental sheep showed an increase of digestibility of dry matter, dry protein, crude fat, crude fiber, bio-effecting agents, as well as increased nitrogen utilization coefficient. Use of the preparation provided increase in daily weight gains.

Objective: This study was aimed at assessing efficiency of the original coniferous energy supplement in the diet of cows at the end of the dry period - beginning of lactation - for improving the energy density of diets, enriching them with vitamins and major and minor nutrient elements, improving milk productivity, and maintaining productive health.Methods: The scientific-production experiment was performed on the basis of the “Lukoshkino” unit of the “Klenovo-Chegodaevo” research farm (Moscow) on twenty cows. The preparation was fed at the rate of 150 g for 20 days before calving and for 30 days after calving.Results: Studies have found the positive effect of the preparation on the average daily milk yield, natural fat content increased by 5.4%-6.9% (with butterfat percentage increased by 0.09%), and reduced cost of feed per unit of obtained product.Conclusion: The use of the preparation promoted enzymatic processes in the rumen, had positive effect on the carbohydrate-lipid and protein metabolism, and had no negative effect on the non-specific resistance of cows.

Correlations between the major biochemical (BC) and antioxidant (TAWSA) parameters of pigs’ blood are necessary to study in order to assess physiological–biochemical status (PhBS), animal health, production, etc. Blood samples were obtained from Duroc breed boars (n = 77), divided into groups 1 (n = 25), 2 (n = 40) and 3 (n = 12), which were fattened for 65, 72 and 100 days, respectively. Significant positive and negative correlations were found between TAWSA and BC parameters of pigs’ blood for group 3: very high in the case of total protein (TP) (−0.75) and aspartate aminotransferase (AST) (−0.79); high in the case of cholesterol (−0.72), glucose (0.66), alkaline phosphatase (0.66), calcium ions (−0.60) and globulins (0.53); moderate in the case of albumins (−0.36), triglycerides (−0.35), magnesium (−0.32) and phosphorus (−0.27). The same was found for group 2: high in the case of TP (0.51); moderate in the case of globulins (0.48), cholesterol (0.33) and phosphates (0.25). The only moderate correlation was found for group 1: magnesium (−0.48), glucose (0.36) and calcium (−0.25). This tendency indicated the stabilization of pig PhBS during growth and fattening, which can be useful for understanding the PhBS and antioxidant features of pigs, the factors of their nutrition, maintenance, etc.

The effects of chitosan as feed additive for animals (FAFAs) on various digestive processes are an important to study because of the animal nutrition and production quality, healthcare and farming. The aims of this study were to evaluate the total amount of water-soluble antioxidants (TAWSA) of chitosan and high protein microbiologically synthesized concentrate as FAFAs; to assess the effect of these FAFAs on TAWSA values, parameters of sheep blood serum and rumen content by biochemical, physical and chemical methods. The laboratory studies of TAWSA values of feed components based on chitosan from different manufacturers or/and a high-protein concentrate were implemented. The animal experiments were carried out on six rumen-fistulated ewes (in three rounds of 14 days each, i.e., three groups) to confirm the results of the laboratory studies. The particular differences of the TAWSA of sheep blood by using both FAFAs by amperometric method were determined. A strong negative correlation −0.67 (or −0.86) was observed between TAWSA and the total protein (globulin’s) content in the blood for the Group 3 of animals. A moderate (0.40) or strong (0.73) positive correlation between TAWSA and total protein content in the blood for the Group 2 of animals than weak correlation 0.23 (or 0.26) for the control Group 1. In conclusion, the correlations between the value changes of TAWSA vs. major biochemical parameters of a blood serum of rumen-fistulated ewes (Group 3 > Group 2 > Group 1) or some indicators of the rumen content (ingesta pH, total content of volatile fatty acids, etc.) were found for the first time.