Effects of Trace Mineral Injections on Measures of Growth and Trace Mineral Status of Primiparous Cows and their Calves.

The objective of this study was to evaluate the effects of injectable trace minerals (ITM) administrations at strategic moments in the beef cattle production cycle. At calving, 50 primiparous cows (Angus × Hereford) and their calves were randomly assigned to 1 of 2 treatments: 1) ITM: cattle assigned to the ITM treatment received an ITM injection at calving and a subsequent administration at breeding (cattle over 2 yr: 1.0 mL/90 kg body weight [BW]; calves: 1.0 mL/45 kg BW); or 2) Control: cattle assigned to the control treatment were administered with saline following the same procedure as the cattle assigned to the ITM treatment. Body weight, blood, and liver samples were collected from dams and calves at multiple time points to evaluate the growth and mineral status of cow-calf pairs. All variables were analyzed using the MIXED procedure of SAS. A treatment effect (P = 0.02) was observed for Cu liver concentration of primiparous cows at breeding. Cows assigned to ITM treatment had greater Cu status than cohorts assigned to Control treatment. No treatment effects were observed for the mineral status or growth of calves. The administration of ITM to primiparous cows enhanced Cu status when grazing Cu forages scarce of Cu.