Pasturing heifers from German Red Pied and German Holstein Frisian breed on pasture grounds not treated with nitrogen fertilizer

On 25 heifers (12 German Red Pied, 13 German Holstein Frisian) measurements of body weight and of blood components were performed at the end of the st alling period and repeatedly in the time the animals were on pasture. Blood samples (V. jugularis) were analysed for acid-base balance, hemoglobin con tent, hematocrite, MCHC, O2CONT, O(2)SAT, O(2)CAP, HHb, COHb, MetHb in whol e blood and for total protein, albumin, creatinine, urea, Ca, Mg, P, Fe in blood plasma. For 19 out of 22 variables significant mean differences could be found between some sampling points. More profound changes concerned alb umin, creatinine, urea, Ca, Mg, P, Fe, COHb, MetHb, pH, pCO(2), BE and HCO3 and less profound Hb, Hk, MCHC, total protein, O(2)SAT and HHb. Mean diffe rences between pasture groups and breeds were evident at some measuring poi nts. Ca, Mg, Fe and Hb and Ilk showed significant negative correlations wit h growth parameters at some sampling points. Strong correlations for creati nine, Fe, Hb, Hk, O2CONT and O(2)CAP between sampling points are an express ion of individual specificity of these variables. Correlations of the chang es of the variables with the starting value at the end of the stalling peri od show, that adaptation took place in an individual and time specific way concerning direction and degree. Results indicate variation causes of usual ly applied clinical-chemical blood measures in young cattle on pasture, whi ch can be explained in relation with food availability and adaptation to en vironmental conditions and should be considered in setting and applying ref erence values.