Effects of an organic source of copper, manganese and zinc on dairy cattle productive performance, health status and fertility

The objective was to determine effects of partially replacing Zn, Cu and Mn in sulphate form with organic trace minerals (OTM) during the dry period and lactation on dairy cow productive performance, fertility and health status, while supplying Zn and Cu to meet National Research Council (NRC; 2001) guidelines for lactating Holstein dairy cows in midlactation and Mn above NRC guidelines. At the beginning of the dry period, 296 pregnant Holstein cows were randomized to one of two experimental groups. During the dry phase, cows were fed a diet where Cu, Mn, and Zn were supplied as sulphates (control group) or a diet in which 500 g/kg of Cu, Mn, and Zn was supplied as sulphates and 500 g/kg as OTM (KeyShureTM). During lactation, cows that had been previously assigned to the control group were fed, for 240 d, a diet where Cu, Mn, and Zn were supplied as sulphates (control group) while cows which had received OTM during the dry phase were fed a diet in which 250 g/kg of sulphates were replaced with similar amounts of organic Cu, Mn, and Zn (OTM). Cows were housed in a free stall barn with four pens (two pens per treatment). Colostrum from cows fed OTM contained more immunoglobulins (+19%; P < 0.01) whereas OTM supplementation had no effect on the concentration of trace minerals in colostrum. During the first 150 d, OTM increased milk fat content by 4.4% (P < 0.05) while milk yield, protein content and somatic cell count were not influenced by treatment. Because more cows from the OTM group became pregnant between 150 and 240 d, a higher number of services per conception (2.01 versus 2.61 for control and OTM, respectively; P < 0.01) occurred in cows fed OTM. Calf mortality at calving was lower in multiparous cows fed OTM (15.6 versus 5.6% for control and OTM, respectively; P < 0.05) whereas there were no differences in other pathologic events and claw disorders. This study produced evidence that partial substitution of Zn, Cu and Mn sulphates with OTM during the dry phase and lactation resulted in higher colostrum immunoglobulins and milk fat, as well as lower calf mortality at calving.