Effect of Mineral Supplementation on Reproductive Efficiency of Beef Cows

Reproductive efficiency is the major component for an economically efficient cow/calf operation and can be influenced by a number of factors such as breed, age, health and nutrition. Among the components of the diet, trace minerals are hypothesized to have a major impact reproductive efficiency in beef cattle. In order to test this specific hypothesis, a study directly evaluating the success of reproductive performance in cows fed complexed trace minerals versus inorganic trace mineral was designed. In this study, 68 cows where equally divided into treatment (cows fed with complexed trace minerals) and control (cows fed with inorganic trace minerals) groups. The cows started being fed 30 days prior to AI (d -30). Twenty-eight days after AI (d 28), all cows where diagnosed for pregnancy and non-pregnant cows where removed from the experiment. Twenty-four days after pregnancy diagnosis (d 52), pregnant cows where submitted to ovum pick-up (OPU) and a second OPU was performed on d 67. Although pregnancy rates did not differ (P = 0.33) between treatment and control, cows fed with complexed trace minerals had increased oocyte recovery (P = 0.03), in vitro embryo production (P = 0.06) and more efficient in vitro embryo production (P = 0.06). In summary, the results from this experiment demonstrated that supplementation of beef cows with a complexed source of trace minerals improves reproductive efficiency when compared to cows fed inorganic source of trace minerals.