PSV-B-19 - Effect of Phi-chrome on Beef Cattle Feedlot Performance in Commercial Conditions in Mexico

Abstract: An observational study was conducted to investigate the effect of Phi-Chrome (chromium propionate) on feedlot cattle performance in commercial conditions in Mexico. Performance data from 116 closeouts of pens involving 7,207 crossbred bulls (25% Bos taurus - 75% Bos indicus) fed 140 d with or without Phi-Chrome were collected from a feedlot located in central Mexico and analyzed; DMI, ADG, and FE of 58 closeouts collected over 2019 (control, 0 ppb Phi-Chrome) was contrasted with the performance of 58 closeouts collected over 2020 (Phi-Chrome, 500 ppb). Data were analyzed by linear mixed models, including fixed effects of treatment (Phi-Chrome; 0 vs. 500 ppb), season of year in which cattle started feeding (spring, summer, fall, and winter), interaction treatment × season, and average initial body weight as covariate (from 324 to 351 kg). The year was fitted as a random effect. There were no treatment × season significant interactions (P ≥ 0.117). Season and treatment main effects were significant (P ≤ 0.024) on DMI and FE and not significant (P ≥ 0.472) on ADG. Average initial body weight was significant (P ≤ 0.001) on ADG and FE, but not significant (P = 0.533) on DMI. The DMI was greater for closeouts of cattle without Phi-Chrome (9.40 kg•animal^-1•d^-1 for Phi-Chrome vs. 9.67 kg•animal^-1•d^-1 for control; P = 0.001). The ADG was not different between treatments (1.73 kg•d^-1 for Phi-Chrome vs. 1.74 kg•d^-1 for control; P = 0.472). The FE was better for closeouts of cattle fed with Phi-Chrome (Gain:Feed: 0.185 for Phi-Chrome vs. 0.180 for control; P = 0.013. Feed conversion ratio: 5.43 for Phi-Chrome vs. 5.56 for control; P = 0.021). This research study suggests that the feed efficiency of beef cattle in feedlot commercial conditions of Mexico is improved ~2.5% by feeding cattle with 500 ppb of Phi-Chrome.