Effects of liver abscess severity and quality grade on meat tenderness and sensory attributes in commercially finished beef cattle fed without tylosin phosphate

Abstract

Strip loin steaks (n = 119) were used to evaluate the association between liver abscess severity and USDA quality grade and meat tenderness and sensory attributes of steaks from finished feedlot cattle. Steaks were used in a 3 × 2 factorial treatment structure using a completely randomized design and were collected at a commercial abattoir located in northwest Texas. All cattle were sourced from a single feedlot and fed a common diet that did not include tylosin phosphate. Treatments were USDA quality grades of Select (SEL) and Low Choice (LC) and liver abscess scores of normal (NORM; healthy liver, no abscesses), mild (M; 1 abscess less than 2 cm in diameter to 4 abscesses less than 4 cm in diameter), and severe (SV; 1 abscess greater than 4 cm in diameter or greater than 4 small abscesses). All steak samples were collected on the same day, approximately 36-h post-mortem and were cut from the left side of the carcass at the 13th rib by a trained abattoir employee. Steaks were vacuum-packaged, and aged at 3 ± 1°C for 14-d post-mortem. Warner-Bratzler Shear Force (WBSF) and Slice Shear Force (SSF) analyses were conducted and cook-loss percentage was measured. A trained sensory panel analyzed samples for juiciness, tenderness, and flavor attributes. There were no differences among liver abscess scores for WBSF or SSF (P > 0.52). Warner-Bratzler Shear Force was lower for LC-SV than SEL-SV (P = 0.04). Sensory attributes of initial and sustained juiciness, and overall tenderness were all greater for LC than for SEL steaks (P < 0.04) and connective tissue amount was less for LC steaks when compared to SEL (P = 0.03). Liver abscess score had no effect on any sensory attributes (P > 0.70); however, there was an interaction between quality grade and liver score for myofibillar tenderness (P = 0.03). Within LC steaks, liver abscess score had no effect on myofibrillar tenderness (P > 0.05), however, in SEL steaks, M steaks were more tender than SV steaks (P < 0.03). These results indicate that within quality grades, meat tenderness or sensory attributes were not influenced by liver abscess score but that mild liver abscesses may affect the myofibrillar tenderness of SEL steaks.

Keywords: cattle; feedlot; liver abscesses; meat tenderness; palatability; quality grade.

Figure 1.

Least square means of effect of liver abscess score on myofibrillar tenderness by USDA quality grade for beef strip loin steaks on a continuous 1 to 100 scale. ^a–dMeans with common letters differ at significance level of P ≤ 0.05. Liver Score Descriptors: None = healthy liver, no abscesses; Mild = 1 abscess less than 2 cm in diameter to 4 abscesses less than 4 cm in diameter; Severe = 1 abscess greater than 4 cm in diameter or greater than 4 small abscesses Number of Observations: Low choice-none: n = 22; Low choice-mild: n = 20; Low choice-severe: n = 20; Select-none: n = 21; Select-mild: n = 20; Select-severe: n = 16.