OBJECTIVE: The aim of the present study was to evaluate different statements in the literature on the influence of the sampling site on various blood parameters in a larger amount of animals. In addition, the practical usability of blood sampling from the udder vein or other accessible veins (e. g. saphenous vein or tail vein) in comparison to the jugular vein for metabolic analyses should be verified.MATERIAL AND METHODS: For this purpose blood samples from 92 cows and heifers were taken from the jugular vein, the udder vein and the saphenous vein of the left and right hind limb at four different time points (from 3 weeks ante partum until 8 weeks post partum) and comparatively investigated.RESULTS: For five of the 16 investigated parameters (free fatty acids, beta-hydroxybutyrate, glucose, creatine kinase, and calcium) partially high significant differences between the sampling sites became apparent, dependant on the moment of analysis.CONCLUSION AND CLINICAL RELEVANCE: In metabolic analyses, which comprise the aforementioned parameters, the blood sampling site has decisively influence and has to be considered in the interpretation. The udder vein represents no alternative for blood sampling in high yielding cows for metabolic analyses. For obtaining meaningful results, the jugular vein has to be used for blood sampling, despite the higher procedural effort. An exception is the determination of the creatine kinase activity. Since defence movements of the animal's neck seem to have an influence on the local activity, the udder vein should be preferred as sampling site.
Animals Biomarkers