Microelement supplementation in dairy cows by mineral lick.

摘要

The aim of this experiment was to verify the option of providing microelement supplementation to dairy cows in the dry period through supplemented mineral lick, and to compare the content of microelements in the blood, colostrum and milk. The experiment was carried out on a farm with Czech Fleckvieh dairy cows (n=20). An experimental group (E), supplied with mineral lick ad libitum enhanced with organic forms of microelements (Se, Zn, Cu, Mn) for four to five weeks before parturition and one week after parturition was formed. The control group (C) did not receive any mineral lick. The use of mineral lick by cows was very uneven, its total consumption oscillated between 0 and 250 g of lick per animal per day. Lick feeding did not result in significant increase of monitored microelements in the cows' blood, colostrum and milk. Only a tendency to increased concentrations of Se and Cu in the blood of group E cows was observed; the average Se concentration increased by 60 micro g/litre (Cu by 9 micro mol/litre), whereas in group C, Se increased only by 30 micro g/litre (Cu by 6 micro g/litre). The concentration of microelements in colostrum after parturition decreased quickly. Significant decreases were determined for Se, Cu and Zn on the first (for Mn on the second) day after parturition. Selenium concentration in the first colostrum was five times higher than in milk, Cu concentration three times higher, Zn concentration four times higher and Mn concentration 1.3 times higher.