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Background: Haptoglobin (Hp) is an emerging diagnostic marker in cattle, and knowledge of suitable sample types and measurement methods is important., Objectives: The aims of this study were to compare the results of a colorimetric assay (CA) and an ELISA for bovine Hp using serum, EDTA plasma, and lithium-heparinized (LH) plasma, respectively, and to assess the diagnostic potential for puerperal metritis., Methods: In experiment 1, Hp was measured in pooled aliquots of serum (n = 10), EDTA plasma (n = 10), and LH plasma (n = 10) of 100 healthy fresh lactating dairy cows from 10 farms using both the CA and the ELISA. In experiment 2, five healthy and five cows with acute puerperal metritis were sampled, and Hp was determined using both assays for all three sample types. In experiment 3, aliquots of serum and LH plasma from cows in different lactation stages were transferred into plain, EDTA-coated, and LH-coated tubes and mixed before colorimetric analyses. Distilled water was also placed into each tube type and treated similarly., Results: Plasma samples measured with the CA showed on average 2.3 (EDTA) and 2.5 (LH) times higher Hp concentrations compared with serum, whereas no differences were seen with the ELISA results between sample types. Based on a clinical cut-off value, both methods differentiated sick from healthy cows. Haptoglobin measurements with the ELISA were less precise compared with CA measurements due to high dilutions. No influence of the anticoagulants on the CA was observed., Conclusions: Due to measurement discrepancies between serum and plasma, CAs for bovine Hp based on peroxidase activity should be performed with serum, or specific reference ranges for plasma samples should be established. In this study, CA results obtained with LH plasma were more precise than results obtained with EDTA plasma. Both the CA and the ELISA are suitable diagnostic tools for the diagnosis of puerperal metritis, but CA measurements were more precise in this study., (© 2024 The Author(s). Veterinary Clinical Pathology published by Wiley Periodicals LLC on behalf of American Society for Veterinary Clinical Pathology.)

Background: Evaluation of mineral profiles including essential and toxic elements in dairy cows provides fundamental information for bovine practitioners during regular herd supervision and monitoring. The present research was designed to investigate the variations of mineral profiles in different blood specimens of dairy cows at different lactation stages., Methods: This study was divided into two parts: the first included 32 cows, which were classified into four groups according to their lactation stages, and the second involved 10 cows at mid-lactation. The concentrations of copper (Cu), zinc (Zn), selenium (Se), manganese (Mn), barium (Ba), strontium (Sr), calcium (Ca), magnesium (Mg), total phosphorous (P), sulfur (S), cobalt (Co), silicon (Si), lithium (Li), nickel (Ni), thallium (Tl), boron (B), aluminum (Al), uranium (U), and arsenic (As) were measured in serum, ethylene diamine tetraacetic acid (EDTA) plasma, heparin plasma, and EDTA whole blood samples., Results: The concentrations of Cu, Zn, Fe, Mn, Ba, and Sr showed significant variations among the dairy cows of different lactation stages ( p < 0.05). Strong regressions were determined between the mineral concentrations in individual and pooled samples ( R 2 = 0.991, p = 0.000). In comparison to other blood sample types, the concentration of Cu, Ba, and Sr was higher in EDTA plasma ( p < 0.000). In addition, the values of Zn, Se, Fe, and Mn were significantly increased in heparin and EDTA whole blood samples. Concentrations of Ca and Mg, and P were higher in EDTA plasma, and EDTA whole blood samples, respectively. Furthermore, the mean values of Si, Li, Ni, and Tl showed significant increases in EDTA plasma, while S values were higher in EDTA whole blood samples ( p < 0.000). Concentrations of Al and U exhibited significant increases in serum samples ( p < 0.000)., Conclusion: Concentrations of Cu, Zn, Fe, Mn, Ba, and Sr undergo physiological variations among dairy cows at different lactation stages. Therefore, caution should be taken during assessment of these minerals. The concentrations of essential and toxic elements, as well as Ca, P, Mg, and S, varied among the different blood sample specimens, indicating their interpretations should be based on this regard. During dairy herd supervision, the use of pool sample, instead of individual ones, for determination of mineral status may be promising to minimize the costs of individual sample measurements. In general, EDTA plasma may be more suitable for measurements of Ca, Mg, P, and S. It seems that EDTA plasma and heparinized plasma are suited for the estimation of Se and Fe, respectively., Competing Interests: Author A-EM was employed by Vet Med Labor GmbH, IDEXX Laboratories. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hussein, Müller and Staufenbiel.)

Introduction: Undersupply and oversupply of dairy cows with essential trace elements should be avoided from the point of view of animal health and environmental pollution. The aim of the study was to proof the results faecal analyzes on the nutritional supply situation with essential trace elements in comparison to measurements from total mixed ration (TMR) analyses. Concentrations of iron (Fe), copper (Cu), zinc (Zn), Mangan (Mn), selenium (Se), cobalt (Co), molybdenum (Mo) were measured as representative multicentric random sample in 574 TMR, 600 pooled faecal and blood samples from dairy cows. Trace elements, Fe in 0 %, Se 18 %, Zn 43 %, Cu 52 %, Co 53 % and Mn 59 %, were within the target range. Undersupply was found in 0 to 8 % and an oversupply in 39 to 100 % of the TMR samples. The tolerance limit for Fe was exceeded in 11 % and for Mo in 13 %. The results indicate the need for optimized ration design. The trace element concentrations in the faecal samples varied over a wide range. Results of pooled faecal samples (n=10 per pool) corresponded closely with the mean values calculated from the individual samples (r2 > 0,9). Correlation between element concentrations in the TMR and faecal samples for Fe (r=0,687), Cu (r=0,675), Zn (r=0,635), Mn (r=0,656), Se (r=0,573), Co (r=0,795), and Mo (r=0,708) were highly significant. No correlations were detected between the element concentrations in the TMR and in the blood samples. The regression analyzes showed a highly significant linear adjustment of the measured value distribution around the regression lines over the entire value range including the zero point. Reference values were calculated for the faecal concentrations of Cu, Zn, Mn, Se and Co. Tolerance reference limits in the TMR were calculated for the faecal concentrations of Fe and Mo. The trace element concentrations in the TMR samples reflect the nutritional supply situation. Knowledge of the nutritional supply situation of the herd is of great importance for the stock management of dairy cow. Fecal sample analyzes can be used as an alternative to TMR examinations to assess the nutritional supply situation.