Influence of trace mineral supplements on the health of cows

The purpose of this work was to determine what influence does the special trace element additives have on the cow milk quantity and composition, the peak milk yield, open days and insemination index. As well as to determine the changes of calcium, magnesium, phosphorus, iron and copper concentration in the blood serum before and after the calving, using mentioned additives For the purpose of this research, 32 Lithuanian Black and White breed dry period cows were selected, 45 days left until planned calving. The selection of cows was based on age, condition and lactation stage, which were as similar as possible. During the dry period and after the calving 16 cows had two feed additives in the form of a bolus, which had 13,4 g. of copper, 1,0 g. iodine, 0,5 g. cobalt, and 0,15 g. selenium in its composition. The rest 16 cows were used for control purposes. Both groups of cows had the same conditions of being held and fed. Before feeding the bolus and after the calving, blood was taken from the cows tail vein (v. coccygea). The blood results were processed in the LUHS academy of veterinary medicine animal reproduction laboratory and levels of calcium, phosphorus, magnesium, iron and copper amounts were determined. Milk samples were picked in the first month after the calving. The milk samples were processed in public company ”Pieno Tyrimai“. Milk fatness, protein levels, lactose, SCC and urea were determined while processing the milk samples. Herd management program had recorded average number of days of peak milk in the lactation, insemination index, milk yield and open days data in cows after calving After distributing the trace element additives, the tested cow group peak milk yield had gotten shorted by 9 days, SCC was reduced by around 177 thousand ml. and the insemination index was reduced as well. During the peak milk yield, the milk amount from one cow increased by an average of 3,7 kg/d., comparing with the control cow group. The days open period gotten longer by 7 days. After the calving, the iron amount in the cow blood test was reduced