Effects of ractopamine hydrochloride and zilpaterol hydrochloride supplementation on longissimus muscle shear force and sensory attributes of beef steers1

• Published in: Journal of animal science Vol. 91; no. 12; p. 5989
• Main Authors: Arp, T S, Howard, S T, Woerner, D R, Scanga, J A, McKenna, D R, Kolath, W H, Chapman, P L, Tatum, J D, Belk, K E
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 01.12.2013
• Subjects: Beef; Cattle; Dietary supplements; Meat processing; Meat quality; Muscular system
• ISSN: 0021-8812; 1525-3163

Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on LM shear force and sensory attributes was determined using pens (n = 40) British x Continental crossbred steers randomly allocated to one of the following treatments: control; RH fed at 200 (RH 200) or 300 mg . steer^sup -1^ . d^sup -1^ (RH 300), or 400 mg . steer^sup -1^ . d^sup -1^ (RH 400) topdressed for the final 30 d of feeding; or ZH fed at 7.5 mg/kg, beginning 23 d before slaughter with a 3-d withdrawal. Two replicates (pens) per treatment were represented in four blocks. Eighteen carcasses per pen were randomly selected and one 5-cm LM sample was removed from both carcass sides to be used for shear force and sensory evaluation. Samples were aged for 14 d, frozen at -28.8 degrees C, and cut into 2.5-cm steaks. All steaks were cooked to an internal temperature of 71.1degrees C before being evaluated for Warner-Bratzler shear force (WBSF), slice shear force (SSF), or being fed to trained sensory panelists. Increasing dose and potency of β-agonist increased WBSF by 4 to 17% and SSF by 5 to 24% (P < 0.05). Steaks from steers fed ZH had higher WBSF and SSF values compared with all other treatments (P < 0.05), whereas steaks from controls and steers fed RH 200 were not different (P > 0.05). Probability of steaks failing to meet shear force standards to be certified tender (WBSF <4.4 kg, SSF < 20 kg) was increased from an initial probability of <0.06 in steaks from steers in the control treatment to 0.10 to 0.20 in steers fed RH 400 or ZH (P < 0.05). No difference was detected in panel ratings for overall tenderness of steaks from steers fed RH 200 compared with controls (P > 0.05). Steaks from steers fed RH 300 and RH 400 were comparable for all sensory attributes; however, both RH 300 and RH 400 were rated lower for overall tenderness than controls (P < 0.05). Panelists failed to detect differences in overall tenderness of steaks from steers fed RH 400 and ZH (P < 0.05). Panelists detected no difference in flavor profile or juiciness among treatments (P > 0.05). Results from this study indicated β-agonists negatively affected beef tenderness and these effects may be more noticeable in steers supplemented with ZH and higher doses of RH. [PUBLICATION ABSTRACT]