Using propylene glycol in dairy cow feeding

The glucoplastic substance propylene glycol was continuously used as a feed supplement in six dairy farms. Furthermore it was applied for the first ti me in one farm with a high rate of ketosis prevalence (28 %). The quantitat ive milk acetone test served as a suitable mean for controlling the effect of propylene glycol on the energy metabolism in the dairy cows. Application of propylene glycol diminishes significantly the number of cows with raise d milk acetone concentrations (greater than or equal to 0,250 mmol/l) on he rd basis. It must be particularly emphasised, that the positive metabolic e ffect of propylene glycol can only be expected, if the feed ration of the c ows meets the basically demands of ruminants generally and the level of mil k yield in the herd using propylene glycol. Feeding management must be stab le without any greater variations. Propylene glycol should be feed from abo ut three weeks ante partum at the end of the dry period to six to ten weeks post partum dependant on the special conditions in the herd especially of the milk yield level. Very important is the homogenous distribution of the propylene glycol in the whole ration without the possibility of selective e ating. Relating to the cost benefit ratio, a price of about 0,40 DM per day and head opposites a lower ketosis prevalence with significant positive ef fects on milk yield and general health. The presented results support using propylene glycol as an important and suitable mean in feeding management o f dairy herds.