Date of this Version
Brasche, C. J. 2015. Effect of a trace mineral injection on beef cattle performance. M.S. thesis, University of Nebraska.
Adequate trace mineral status is important in beef cow/calf and replacement heifer systems because trace minerals play vital roles in reproduction, immunity and growth. Many experiments have investigated the use of a trace mineral injection containing Cu, Mn, Se and Zn (TMI) on growth and immunity of beef cattle. However, very few have investigated TMI use on reproductive performance. Therefore, five experiments, a two year cow/calf experiment, and four replacement heifer experiments were designed to investigate the use of a TMI on reproductive performance of cows and heifers, calf growth and trace mineral status of cows, heifers, and calves. The use of the TMI at pre-calving and pre-breeding did not consistently improve reproductive performance of heifers and cows with good trace mineral statuses that were receiving supplemental trace minerals. There were no differences (P ≥ 0.36) in the AI pregnancy rate [48 and 38% control (CON) vs 44 and 39% TMI, year 1 and year 2, respectively] or overall pregnancy rate (93 and 93 % CON vs 93 and 90% TMI, year 1 and year 2, respectively) of cows receiving a TMI when compared to control cows during the two year trial. In experiment 1 beef heifers (Angus´Hereford´Simmental) were bred to fixed time AI, TMI heifers had increased overall pregnancy rates (83 vs 92%, CON vs TMI, respectively; P = 0.02). In experiment 2 beef heifers were AI bred to synchronization response, TMI had no effect (78 vs 83%, CON vs TMI, respectively, P = 0.46). Conception rates to AI and overall pregnancy were not affected by TMI use in two experiments using Black Angus beef heifers being developed in a dry lot fed adequate trace minerals in a total mixed ration. Growth of suckling calves measured as birth weight, average daily gain, actual weaning weight, and 205 d adjusted weight were not influenced by TMI. However, trace mineral status of all groups of cattle were increased with use of TMI. In heifers liver Cu and Se were increased (P < 0.02) 25 d post injection. The use of a TMI was effective in increasing (P < 0.05) liver concentration of Cu and Se in cows prior to breeding 15-18 days after receiving injections. In calves, the use of the TMI enhanced (P < 0.05) plasma concentrations of Mn, Se and Zn at branding and increased liver concentrations of Cu and Se at weaning. In conclusion these series of experiments demonstrate that use of a TMI can increase trace mineral status of animals. However, influences on performance are dependent on the trace mineral status of the animals and increases in performance are not seen in animals with adequate status.
Advisor: Mary E. Drewnoski