Physiological and ecological aspects of macroelement supplementation for cattle

The concentration of Ca, Na and K was investigated in urine in dairy and beef cows in the Sumava mountains in 1998 and 1999. A goal of this study was to review saturation of animals by macroelements and the potential risks of disruption of the macroelements circulation in environment caused by their unproportional supplementation. There was found extreme high individual variability in the content of Ca and Na which is related to the unsuitable supply of minerals at pastures and at free housing. The beef cows had significantly lower concentration of Ca in urine in the mountain area in winter in comparison with dairy cows in the mountain and slope areas. In dairy cows in slope area a high content of Ca in urine with potential physiological and ecological consequences. The concentration of Na in urine was low in all groups of cows. This finding is related to its low content in roughage being rich in K. This ascertainment was also manifested by the high concentration of K in urine. In order to adjust this status it is necessary to increase the supplementation of Na with regard to the relation to K.