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Investigation of the metabolic status of cows in early lactation is the most important measure in assessing the health and productivity of cattle. Today, the analysis of metabolites, hormones and blood in the early lactation can be largely predicted health risk and of cows productivity. The daily work of veterinarians are available to a large number of markers in the blood that indicate the energy balance (NEFA, BHB, glucose), the balance of proteins (albumin, total protein, urea), the balance of ions (Ca, P, Mg), inflammatory response (blood pictures, inflammatory proteins), oxidative status (SOD, MDA), status of the liver (bilirubin, AST, ALT), hormonal (insulin, cortisol, IGF-I, STH, T3, T4) and hematology finding. In addition to the assessment of the metabolic status must be considered body condition of the cows and the amount of milk production. The aim of this study was to investigate the correlation between these parameters and to determine what parameters by whose determination can be seen overall metabolic status of cows. In this way we will make the extraction of information from large amounts of data, so we will focus only on those elements of the metabolic and endocrine profile that has the most reliable to describe the metabolic status of cows . In this way we will make the rationalization of laboratory testing metabolism cows. Blood was taken from 50 cows of the Holstein - Friesian breed. The concentration of the above- mentioned parameters were determined. They are made of the correlation matrix and then by extraction of the main factors using factor analysis. The results show that the extract may by three main factors. Factor 1 explains 61.7% of the variation, and it highly correlates with the values of insulin, IGF-I, STH, NEFA and glucose (metabolic stress). Factor 2 explains 20.2% of variation and on highly correlated with the BHB, AST, triglycerides and cholesterol (a liver). Factor 3, which explained 7% of the variation variables correlated with milk production in cows (productivity). [ABSTRACT FROM AUTHOR]

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.