The Impact of Trace Mineral Source, Water Quality, and Short-Term Choline Supplementation on Performance and Carcass Characteristics of Finishing Steers12

A total of 288 yearling steers (315.2 ± 3.7 kg) were used to determine the effects of trace mineral source, water quality, and short-term choline supplementation on feedlot performance and carcass characteristics. Trace mineral treatments consisted of 1) a control, namely, 15 mg Cu/kg DM, 20 mg Mn/kg DM, and 45 mg Zn/kg DM supplemental trace minerals in inorganic form; and 2) organic (proteinate form) iso-concentrations to the inorganic trace minerals composed of 50% organic and 50% inorganic trace minerals. Water treatments consisted of 1) a blend of reverse-osmosis (RO) water and well water (1,072.4 mg sulfate/L) and 2) well water (2,377.5 mg sulfate/L). At 29 d before slaughter, 4 pens of steers per trace mineral × water treatment combination were supplemented with choline at a rate of 20 g of rumen-protected choline/steer daily, and the remaining 4 pens served as the controls (no supplemental rumenprotected choline). There were no effects of trace mineral source, water quality, or interactions with feeding period for BW, ADG, DMI, or G:F. Initial and final BW, ADG, DMI, and G:F were similar across trace mineral and water treatments. Choline supplementation for only the last 29 d on feed did not affect performance. Morbidity, mortality, and percentage of retreated cattle were similar across trace mineral and water treatments. There was a trace mineral × water quality interaction (P < 0.04) for marbling score. For steers receiving inorganic trace minerals, marbling score was lower for steers consuming well water than for steers consuming a blend of RO water and well water. Steers receiving organic trace minerals had an improved (P < 0.03) USDA YG compared with steers receiving inorganic trace minerals. Steers consuming well water tended (P < 0.08) to have greater LM area and lower (P < 0.08) calculated YG than steers consuming the RO water blend. Carcasses from steers fed supplemental choline were less likely (P < 0.01) to qualify for the USDA YG 4 and 5 categories. Other carcass characteristics were not affected by water quality, trace mineral source, or choline supplementation. Results of this experiment indicate that water quality, trace mineral source, and short-term choline supplementation (29 d) had no effect on animal performance and minimal effects on carcass characteristics.