The experiment was conducted between May 2007 and February 2009 at a commercial farm near Verona (Italy). At the
beginning of the planned dry period of 60 d, 296 pregnant Holstein cows, including 111 heifers, were randomized to one of
two experimental groups with 147 and 149 in the control and organic trace minerals (OTM) groups based on homogeneity of
milk yield (sire predicted transmitting ability was used for primiparous cows) and parity. During the dry period, cows were
fed a diet