Effect of injectable trace mineral supplementation on grazing beef cow and calf performance in Western Canada

A 3-year study evaluated an injectable trace mineral (ITM) product (Multimin ® 90) containing Cu, Mn, Se, and Zn on beef cow and calf performance. Each year, cows were blocked by age, stratified by body weight (BW), and randomly allotted to 1 of 2 treatments, either (i) ITM + granular 2:1 trace mineral (ITM; n = 9 797 100/year); or (ii) granular 2:1 trace mineral alone (CON; n = 98 100 101/year). The ITM was given at 4 weeks pre-calving (PC) and 4 weeks pre-breeding (PB). Cow BW and body condition score (BCS) were evaluated at ITM administration and at fall pregnancy testing (PT). Blood serum mineral concentrations were evaluated at PC, PB, and PT. Serum mineral concentrations at PC, PB, and PT did not differ ( p > 0.05) between groups. However, Cu levels at PT increased ( p = 0.03) for ITM (0.49 ppm) compared to CON cows (0.43 ppm). Over 3 years, average pregnancy rates were 92.1 and 90.6% for ITM and CON cows ( p = 0.57). Cow BW and BCS did not differ ( p > 0.05), and calves born to ITM cows did not differ ( p > 0.05) by birth weight or weaning weight. Future studies should include more cows with greater variability in initial trace mineral status.