Metabolic stress in early lactation cows is characterized by lipolysis, ketogenesis, insulin resistance and inflammation because of negative energy balance and increased use of lipids for energy needs. In this study the relationship between lipid metabolite, lipid-based insulin resistance, and hepatocyte functionality indexes and tumor necrosis factor alpha (TNF-α) with extracellular heat shock protein 70 (eHsp70) was investigated. The experiment included 50 cows and all parameters were measured in blood serum. In cows with a more pronounced negative energy balance, the following was determined: a higher concentration of eHsp70, TNF-α, non-esterified fatty acid (NEFA), beta-hydroxybutyrate (BHB), NEFA to insulin and NEFA to cholesterol ratio and lower concentration of cholesterol, very low-density lipoproteins (VLDL), low density lipoproteins (LDL) and liver functionality index (LFI). The eHsp70 correlated negatively with the values of cholesterol, VLDL, LDL, and triglycerides, while correlated positively with the level of NEFA and BHB. A higher concentration of eHsp70 suggests the development of fatty liver (due to a higher NEFA to cholesterol ratio and lower LFI) and insulin resistance (due to a lower revised quantitative insulin sensitivity check index RQUICKI-BHB and higher NEFA to insulin ratio). The eHsp70 correlated positively with TNF-α. Both TNF-α and eHsp70 correlated similarly to lipid metabolites. In cows with high eHsp70 and TNF-α values we found higher concentrations of NEFA, BHB, NEFA to insulin and NEFA to cholesterol ratio and a lower concentration of triglycerides and VLDL cholesterol compared to cows that had only high TNF-α values. Based on the positive correlation between eHsp70 and TNF-α, their similar relations, and the additional effect of eHsp70 (high TNF-α + eHsp70 values) on lipid metabolites we conclude that eHsp70 has pro-inflammatory effects implicating lipolysis, fatty liver, and fat tissue insulin resistance.

Previous experimental models on cows have examined the difference in the metabolic adaptation in cows after niacin administration, without identifying the most important mediators between niacin administration and its biological effects, namely active forms of niacin. All tissues in the body convert absorbed niacin into its main metabolically active form, the coenzyme nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). The aim of this study was to determine the influence of niacin administration in periparturient period on NAD, NADP and the NAD:NADP ratio and to determine relationship between these indicators of an active form of niacin with metabolic parameters in cow blood. The study included 90 healthy cows: 45 cows receiving niacin and 45 cows were negative control. The niacin group was treated with nicotinic acid for two weeks before, as well as two weeks after parturition. Nicotinic acid was applied per os with feed. In cows receiving niacin, there was a significantly higher concentration of NAD and NADP, but the NAD:NADP ratio did not differ compared with control. All three indicators were able to separate cows who received and who did not receive additional niacin. NAD and NADP are good indicators of the availability of niacin from additional sources. The NAD:NADP ratio is a good indicator of the biological effect of applied niacin on metabolites in cows due to its correlation with a number of metabolites: positive correlation with glucose, insulin, glucose to insulin ratio and the revised quantitative insulin sensitivity check index (RQUICKIBHB) of insulin resistance, triglycerides and cholesterol, and a negative correlation with nonesterified fatty acid (NEFA), beta hydroxybutyrate (BHB), gamma-glutamyltranspherase (GGT) and urea in cows receiving niacin. The same amount of added niacin in feed can produce different concentrations of NAD, NADP and NAD:NADP in the blood, and this was not related to their concentration before the addition of niacin. The change in the concentration of the active form of niacin (NAD, NADP and NAD:NADP) further correlates with the concentration of metabolic parameters, which indicates that the intensity of the biological effect of additional niacin can be accurately determined only if we know the concentrations of its active forms in blood. Under basal conditions (without additional niacin), active forms of niacin that already exist in the blood do not show significant correlations with metabolic parameters.

Background: Iron (Fe) is microelement, essential to ensure some metabolic physiological process. Although Fe is a stable element in the body that is tightly regulated, metabolic stress, lipolysis, ketogenesis, endocrine change, insulin resistance and inflammation in early lactation can influence Fe status in blood. The objectives of this experiment were to determine the Fe status of cows in early lactation and determine whether measures of Fe status were in relation with hematological, metabolic, endocrine and inflammatory response in cows during early lactation. Materials, Methods and Results: The experiment included 30 healthy cows in the 1st 6 weeks of lactation. Laboratory analysis includes determination of Fe status (blood Fe, unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), transferrin saturation percentage (TS%) and metabolic response of cows (complete blood count, non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), cholesterol, triglycerides, glucose, total bilirubin (TBIL), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), cortisol, T3, T4, insulin, RQUICKIBHB, TNF-α, and haptoglobin). Blood samples were collected by puncture of coccygeal vein. Fe increased from the 1st to the 6th week of lactation, with significantly lower concentrations in the 1st 2 weeks of the experiment (P < 0.01). TIBC and UIBC were lower in 1st 2 or 3 weeks of experiment (P < 0.01), while the TS% was unchanged. Hematological response included a significant lower MCV and HCT (P < 0.01) and tendency to decrease HGB and RBC (P < 0.1) in 1st 3 weeks of lactation compared to 2nd 3 weeks. WBC and PLT was unchanged, but NLR was higher in 1st 3 weeks of lactation (P < 0.05). Metabolic response was characterized by higher concentration of NEFA, BHB, TBIL, AST, GGT (P < 0.01) and NEFA:CHOL ratio (P < 0.05), and lower concentration of GLU, TGC, CHOL (P < 0.01) and ALB (P < 0.05) in 1st 2 or 3 weeks of lactation compared to period from 4 to 6 week. Endocrine response included lower concentration of insulin (P < 0.01), T3 and T4 (P < 0.1), and higher concentration of cortisol and RQUICKIBHB index of insulin resistance (P < 0.01) in 1st 2 or 3 weeks of experiment compared to period from 4 to 6 weeks. Inflammatory response included higher concentration of TNF-α and haptoglobin (P < 0.01) in 1st 2 or 3 weeks of experiment compared to period from 4 to 6 weeks. Fe concentration showed significant positive correlation with TIBC, UIBC, HGB, MCV, GLU, T3, T4 and INS and negative correlation with NLR, NEFA, BHB and RQUICKIBHB. TIBC and UIBC showed negative correlation with TBIL, AST, GGT, and NEFA:CHOL ratio and positive with ALB and TGC. Fe showed negative correlation with TNF-α, while TIBC and UIBC showed negative correlation with haptoglobin. Metabolic and inflammatory parameters had higher magnitude of change when Fe was extrapolated on deficit level (9 μmol/L), compared to TIBC, UIBC, TS% and red blood cell parameters as functional indicators of Fe status. Discussion: Fe, TIBC and UIBC showed significant change in 1st 6 weeks of lactation. Decrease in Fe in cows could be related to general homeorhetic adaptation to the onset of lactation, since Fe correlates with indicators of lipolysis, ketogenesis, and endocrine parameters. The lower TIBC and UIBC observed in cows in 1st 3 weeks when Fe was lower is an unexpected finding, since Fe decrease usually increases TIBC and UIBC. TIBC correlates with hepatocytes indices of the functional status and lipid infiltration, so it is possible that TIBC decreases because of changes in lipid metabolism and acute response in the liver. Blood Fe, TIBC and UIBC can be useful indicators for assessing metabolic stress in early lactating cows. Keywords: cow, iron, early lactation, metabolic stress.

Hemolysis is a common cause of errors in laboratory tests as it affects blood parameters and leads to a positive or negative bias. This study aims to examine the relationship between the level of hemolysis (expressed as cell-free hemoglobin concentration, g/L) and the variability of metabolic and endocrine parameters and to determine the threshold level of hemolysis that causes an analytically and clinically significant bias for the twenty most frequently examined blood parameters in cows. Paired blood samples of 10 mL each were obtained from 30 cows. One was subjected to mechanical trauma and plasma was extracted directly from the other. Hemolyzed and non-hemolyzed samples from the same animal were mixed to obtain final samples with cell-free hemoglobin concentrations of 0, 1, 2, 4, 6, 8, and 10 g/L. Metabolic and endocrine parameters were measured in the samples and their deviation and the linear equation between the level of hemolysis and the deviation were determined. The following threshold values of hemolysis were determined, which correspond to the acceptable analytical (lower value) and clinical (upper value) levels of parameter variability: BHB 0.96 and 4.81; NEFA 0.39 and 3.31; GLU 0.38 and 3.90; ALB 1.12 and 6.11; TPROT 1.40 and 6.80; UREA 6.62 and 20.1; TBIL 0.75 and 5.65; AST 0.11 and 2.18; GGT 1.71 and 8.90, LDH 0.01 and 0.11, ALP 0.97 and 2.95; TGC 1.56 and 15.5; CHOL 1.29 and 8.56; Ca 5.68 and 25.7; P 0.57 and 8.43; Mg 1.10 and 8.47; INS 1.15 and 3.89; T3 8.19 and 15.6; T4 8.97 and 18.5; and CORT 2.78 and 11.22 g/L cell-free hemoglobin. Three decision levels are available for each metabolic and endocrine parameter: if hemolysis is below the lower (analytical) threshold value, results can be reported without restriction; if hemolysis is between the lower and upper thresholds, the results can be issued with guidance in the form of corrective linear equations; and if hemolysis is above the upper (clinical) threshold, the results and sample must be discarded. This method contributes to an optimal approach to hemolysis interference with metabolic profile parameters in blood samples from cows.

Background/Objectives: Early lactation in high-producing dairy cows is a critical period characterized by pronounced negative energy balance, enhanced lipomobilization, and the development of insulin resistance (IR), often accompanied by low-grade systemic inflammation. This study aimed to investigate the dynamics of inflammatory markers and IR indices in early-lactation cows, assess their interrelationships, and evaluate the effects of NSAID administration. Methods: Thirty Holstein–Friesian cows were included and allocated into a control group (n = 15) and a treatment group (n = 15), which received ketoprofen (3 mg/kg BW intramuscularly) during the first postpartal week. Blood samples were collected at weeks 0, 1, and 2 postpartum to measure TNF-α, IL-1β, haptoglobin, fibrinogen, NEFA, glucose, and insulin concentrations. Surrogate indices of IR, including RQUICKI, HOMA-IR, QUICKI, and Adipo-IR, were calculated. Results: In the control group, TNF-α, IL-1β, haptoglobin, fibrinogen, and NEFA progressively increased over the first two weeks, accompanied by elevated adipose tissue IR, evidenced by decreased RQUICKI and increased Adipo-IR. Positive correlations were observed between inflammatory markers and NEFA, as well as between TNF-α and IL-1β with Adipo-IR. Conversely, negative correlations were found between inflammatory markers and glucose and insulin, and between TNF-α and RQUICKI, as well as IL-1β and haptoglobin with glucose. Conclusions: Ketoprofen administration significantly reduced inflammatory markers and NEFA while improving RQUICKI and Adipo-IR, without altering the overall relationships among the parameters. These findings indicate that inflammatory cytokines and adipose tissue IR indices serve as reliable parameters for monitoring the interaction between inflammation and IR, and for assessing the metabolic effects of NSAID treatment in early-lactation cows.

Rodents represent one of the most significant biotic hazards in food industry facilities. Their presence can cause direct contamination of food with feces, urine, and hair, as well as indirect contamination through the transmission of pathogenic microorganisms such as Salmonella spp., Listeria monocytogenes, and Leptospira spp. Modern food safety standards (HACCP, BRC, IFS, ISO 22000) require food businesses to establish a systematic pest control approach based on the principles of Integrated Pest Management (IPM). This review presents current scientific knowledge and practical achievements in the field of rodent control in the food industry.