Juckel, Jordan2019-03-132019-03-132018-12https://hdl.handle.net/11299/202086University of Minnesota M.S. thesis. 2December 018. Major: Animal Sciences. Advisor: Ryan Cox. 1 computer file (PDF); viii, 68 pages.The objective of this study was to determine how backgrounding beef cattle affects carcass characteristics, as well as fresh and processed beef quality. The impact of utilizing a moderate energy backgrounding diet was evaluated using 95 crossbred steers (initial body weight: 329.5 ± 16 kg) that were randomly assigned to 1 of 15 pens. Each pen was randomly assigned to one of two dietary treatments. Dietary treatments included a traditional high energy (HigE) finishing diet (n = 7) or a moderate energy (ModE) backgrounding diet (n = 8). HigE cattle were fed a high energy finishing diet for all 193 d; ModE cattle were fed the moderate energy diet for 63 d followed by 130 d the same as HigE. All steers received Revalor®-XS on d 1. Steers were weighed every 28 d. Upon completion of feeding treatment, steers were slaughtered at a commercial abattoir. Hot carcass weight (HCW), 12th rib backfat (BF), ribeye area (REA), marbling score, USDA Yield Grade, USDA Quality Grade, and percent kidney, pelvic, and heart fat (KPH) were recorded 48 h postmortem. Two steers were randomly chosen from each treatment pen for further meat evaluation. Strip loins (IMPS #180) were retrieved and first evaluated for vacuum purge loss and objective backfat color. The strip loins were then fabricated into 2.54 cm thick steaks for evaluation of drip loss, Warner-Bratzler shear force (WBSF), sensory evaluation, and subjective and objective color score evaluation. Shoulder clods (IMPS #114) were ground and evaluated for ground beef retail shelf life (objective and subjective color). Bologna was then made using the remaining ground beef and was evaluated for objective and subjective color, as well as sensory evaluation. Carcass and fresh meat data were analyzed using the mixed procedure of SAS® (Version 9.4) with treatment as a fixed effect and pen as a random effect. Pen was the experimental unit. Sensory data were analyzed using the mixed procedure of SAS® (Version 9.4) with treatment as a fixed effect and panelist as a random effect. Significance was determined at p ≤ 0.05, while trends were determined at p ≤ 0.10. There was no treatment effect on HCW (0.16), BF (P = 0.51), REA (P = 0.82), YG (P = 0.44), or KPH (P = 0.85). However, marbling was higher for HigE cattle (P = 0.02). For steaks, no moisture loss attributes differed between treatments: purge loss (P = 0.40), drip loss (P = 0.41) and cook loss (P = 0.71). Backfat a* (P = 0.43) and b* (P = 0.18) values were not affected by treatment, however, L* (P = 0.06) tended to be higher for HigE cattle. Warner-Bratzler shear force values of strip steaks did not differ between treatments (P = 0.72). There were no treatment effects for any of the steak subjective sensory attributes evaluated: overall liking (P = 0.85), flavor liking (P = 0.78), texture liking (P = 0.55), toughness (P = 0.45), juiciness (P = 0.76), and off-flavor (P = 0.40). Steak objective color score did not differ between treatments: L* (P = 0.39), a* (P = 0.55), and b* (P = 0.68). Steak subjective color (P = 0.11), discoloration (P = 0.21), and desirability (P = 0.10) scores also showed no differences between treatments. Ground beef objective color scores did not differ between treatments: L* (P = 0.41), a* (P = 0.51), b*(P = 0.49). Ground beef subjective color (P = 0.23), discoloration (P = 0.29), and desirability (P = 0.32) did not differ between treatments. Bologna objective L* (P = 0.18), a* (P = 0.98) and b* (P = 0.99) values did not differ between treatments. There was no difference in subjective color analysis for bologna samples: color (P = 0.78), discoloration (P = 0.61), desirability (P = 0.58). Sensory analysis for bologna found no differences in overall liking (P = 0.21), flavor liking (P = 0.36), texture liking (P = 0.49), toughness (P = 0.16), juiciness (P = 0.63), or off-flavor (P = 0.87). Overall, feeding a backgrounding diet before finishing led to similar carcass characteristics with a lower reliance on concentrate feed ingredients.enBackgroundingBeef QualityThesis or Dissertation