ToxStrategies’ scientist Jennifer van de Ligt collaborated with a team of industry scientists to compare tissue cobalt concentrations and growth performance of beef cattle fed various sources of cobalt. Cobalt is an essential trace mineral required for ruminal vitamin B12 synthesis, but sources differ as to ruminal microbial utilization. Cattle were supplemented at two feeding levels with two currently used cobalt sources—cobalt carbonate and cobalt acetate—and one new source of cobalt—cobalt lactate. Growth performance and carcass characteristics were similar for steers fed all cobalt sources and feeding rates. Liver, kidney, muscle, and adipose cobalt concentrations were similar across all cobalt sources but were higher when cobalt exposure increased. The study demonstrated that feeding cobalt lactate, a new cobalt source, resulted in similar growth performance, carcass characteristics, and tissue cobalt concentrations when compared with cobalt acetate and cobalt carbonate.