Ractopamine Hydrochloride Did Not Impact Carcass Traits, Muscle Fiber Types, or Sensory Traits of Long-Fed Yearling Heifers

Abstract

Crossbred heifers (n = 64; animal was the experimental unit) were assigned to 1 of 8 treatments in a 4 × 2 factorial arrangement, with 4 treatment days-on-feed (DOF; 79, 100, 121, 142) and 2 levels of ractopamine hydrochloride (RAC) supplementation (0 or 300 mg × hd–1 × d–1). At 24 h postmortem, carcass traits were determined by trained personnel and longissimus samples were removed for muscle fiber type analyses. Boneless strip loins (IMPS #180) were fabricated and vacuum-packaged at 24 h postmortem and aged for 21 d, cut into 2.54 cm thick steaks, then frozen for no longer than 6 mo. After thawing for 24 h, Warner-Bratzler shear force (WBSF) and trained sensory panel analyses were conducted. Marbling was greater (P < 0.05) for control (CON; 0 mg x hd-1 x d-1 ractopamine hydrochloride) heifers than RAC heifers fed for either 79 or 100 d, but lower (P < 0.05) for CON heifers than RAC heifers fed for either 121 or 142 DOF. Feeding RAC had no effect (P > 0.05) on carcass traits, muscle fiber histology, or meat quality. The addition of RAC had no effect (P > 0.05) on Warner-Bratzler shear force. Feeding RAC had no negative impacts on carcass traits or meat quality and actually improved marbling scores in longer-fed heifers.

Effects of Ferulic Acid Supplementation on Growth Performance, Carcass Traits and Histochemical Characteristics of Muscle Fibers in Finishing Pigs

“…For some meat consumers, one of the most important factors affecting the purchasing decision is the amount of intramuscular fat [ 35 ]. In our study, FA supplementation decreased subcutaneous fat deposition without affecting marbling scores, obtaining a better score than others reported by ractopamine [ 29 , 36 ]. Similarly, the meta-analysis carried out by Andretta et al [ 5 ] indicated that ractopamine significantly reduces backfat thickness, but without affecting intramuscular fat content.…”

Cattle and carcass performance, and life cycle assessment of production systems utilizing additive combinations of growth promotant technologies

“…Supplementation with RH did not improve the HCW or LM area of the BA treatment compared to IMP but resulted in advanced carcass maturity. Others have reported no difference in HCW ( Quinn et al, 2008 ; Strydom et al, 2009 ; Hales et al, 2016 ; Hunter-Beasley, et al, 2018 ; Trotta et al, 2019 ) or LM area ( Walker et al, 2006 ; Quinn et al, 2008 ; Strydom et al, 2009 ; Hales et al, 2016 ; Hunter-Beasley, et al, 2018 ) of RH supplemented cattle compared with non-supplemented controls. However, it is unclear why the LM area of BA was 4.6 cm 2 smaller than IMP in the present study.…”

“…Limited information exists regarding the influence of monensin and tylosin on KPH, however, the increase in KPH of steers in the ANT treatment compared to NT may be due to increased days on feed, not a direct result of these supplements. Increasing days on feed has been shown to increase KPH ( Hunter-Beasley et al, 2018 ).…”