A Meta-Analysis on the Effects of Backgrounding Strategy on Feedlot and Carcass Performance

Utilizing a meta-analysis approach we modeled how backgrounding (BK) strategies: high energy feeding (HE), ad libitum forage or restricted energy feeding (RE), grazing dormant (G) or wheat pastures (WW) affected feedlot and carcass performance. Data were derived from 32 manuscripts (20 drylot and 12 grazing studies) containing 158 treatment means. Multiple regressions were conducted using mixed models to describe effects of BK ADG, days on feed (DOF) and strategy on finishing phase DMI, ADG, final BW, HCW, marbling score, LMA, and fat depth. Greater BK ADG and longer DOF resulted in greater (P < 0.05) DMI during finishing (R² = 0.62). Cattle fed HE during BK had lower (P < 0.05) DMI during finishing than those consuming RE during BK or those grazing G or WW pastures (P < 0.05). Greater ADG or longer DOF during BK resulted in lower ADG during finishing (R² = 0.294). A change in BK ADG of 0.1 kg or 15 DOF had an equivalent impact on ADG during finishing. The relationship between DMI and ADG during finishing was best represented (P = 0.03) by equations for each BK strategy. Gain during BK interacted with strategy to impact final BW and HCW (R² = 0.453 and 0.463). In spite of greater BK ADG, cattle fed HE during BK had lighter (P < 0.03) final BW than those fed RE or grazing. Similarly, cattle fed RE during BK had lighter final BW than those grazing G (P = 0.0014) or WW (P = 0.0104). Correspondingly, cattle fed HE or RE during BK had lighter (P < 0.001) HCW than those that grazed. Differences observed for HCW were mirrored by differences in LMA; carcasses of cattle fed HE during BK had smaller (P < 0.04) LMA than those that grazed while RE trended (P = 0.0579) smaller (R² = 0.385). Fat depth responded inversely to BK energy supply; cattle that grazed had carcasses with greater (P < 0.05) fat depth than those of cattle that were fed RE or HE (R² = 0.314). Strategy during BK had no impact on marbling score, but end weight after BK did. Cattle fed to weights greater than 385 kg during BK, regardless of strategy, had carcasses with lower (P = 0.043) marbling scores (R² = 0.343). Therefore, restricting energy intake during backgrounding resulted in greater carcass weight but prolonging backgrounding resulted in lower marbling.