Effect of Supplemental Chromium on the Growth Performance and Health of Stocker/Grower Cattle

The objective of this study was to determine if providing supplemental chromium (as chromium propionate) to stocker/growing cattle improves growth performance and/or health status. The effect of chromium supplementation during a 70 d growing period on subsequent finishing (263 d average) performance was also evaluated. Two hundred forty crossbred steer calves (260 ± 49 kg) were blocked by source and housing unit such that each of 3 cattle sources were housed in a separate facility. Steers within each block were randomly assigned to 32 pens and two dietary treatments. Steers were fed one of two pelleted grain mixes (control or 640 ppb Cr, as-fed) at the rate of 1.25% of body weight along with mixed grass hay (mostly brome/orchardgrass) ad libitum in a 70-day grower trial. The chromium containing grain mix supplement was formulated to provide approximately 300 ppb Cr from chromium propionate in the complete diet, as-fed. Steers were weighed individually and all feed/orts were weighed and recorded on a pen basis. Pen was considered the experimental unit. Chromium supplementation tended to improve rate of gain from day 14 to 28 (0.40 to 0.54 ±0.53 kg/d; P = 0.074) and over the initial 28 days in the feedlot (0.86 to 0.96 ± 0.036 kg/d; P = 0.058). The efficiency of feed utilization also tended to improve with chromium supplementation from day 0 to 28 (0.126 to 0.139 ± 0.005; P = 0.051). From day 28 to 55, steers on the control diet exhibited some compensatory gain; which was not significant (P > 0.10). Steer performance subsequent to day 28 and for the overall 70-day trial was not influenced (P > 0.10) by chromium supplementation. The greatest advantage to chromium supplementation occurred from day 14 to 28 when steers had some respiratory disease challenges. During that period, mean rate of gain and gain:feed ratio was 35 and 30% greater for steers receiving supplemental chromium than for control steers. Chromium supplementation during the 70-day growing phase did not influence subsequent finishing growth performance or carcass traits, except for a slight decrease in marbling score and quality grade. In conclusion, despite interim differences, chromium supplementation did not improve overall steer performance.