Effects of Zilpaterol Hydrochloride Supplementation on Growth Performance, Carcass Characteristics and Meat Quality for Steers Differing in Breed Type

To determine the effects of zilpaterol hydrochloride (ZH) on growth performance, carcass characteristics and meat quality for steers differing in breed type, steers with British (B; n = 76) or British × Continental (BC; n = 57) backgrounds were allocated to a randomized incomplete block design with a 2 × 2 treatment structure. Pens within each block × breed type were randomly assigned to either ZH (8.3 mg/kg of DM; fed for 20 d before slaughter, followed by a 3-day withdrawal) or control (CON; 0 mg/kg ZH). Steers were subjected to ultrasound immediately before ZH inclusion and following withdrawal to determine the influence of ZH on changes in longissimus muscle area (LMA), fat thickness and percent intramuscular fat (IMF). Carcass data were collected, and the longissimus lumborum was collected for analysis of tenderness, moisture percentage, crude fat content, collagen content, postmortem proteolysis and sensory attributes. The ZH × breed type interaction did not influence (p > 0.05) the feedlot performance, carcass or meat quality attribute traits evaluated, with the exception of moisture percentage. Responses among breed types were as expected for B vs. BC cattle types. Supplementation with ZH improved (p < 0.05) LMA and yield grade but increased Warner-Bratzler shear force.

Beef color and tenderness response to production systems utilizing additive combinations of growth-promotant technologies

The objective of this study was to compare the influence of beef production systems using additive combinations of growth-promotant technologies on meat quality. Steer calves (n = 120) were assigned to 1 of 4 treatments: 1) no technology (NT; control), 2) antibiotic treated (ANT; NT plus therapeutic antibiotics, monensin, and tylosin), 3) implant treated (IMP; ANT plus a series of three implants), and 4) beta-agonist treated (BA; IMP plus ractopamine-HCl). Muscle biopsy samples from the longissimus lumborum were extracted from a subset (n = 4 per treatment) of steers to evaluate expression of calpain-1, calpain-2, and calpastatin using real-time RT-PCR. Following carcass chilling, objective color (L*, a*, and b*) was evaluated. The right strip loin was removed from each carcass, portioned into 2.54-cm steaks, and designated to 7, 14, or 21 d postmortem aging periods for analysis of cook loss and Warner-Bratzler shear force (WBSF). The anterior face of each strip loin was used for analysis of crude fat and moisture. Treatment influenced (P < 0.001) L*, a*, and b*. The NT and IMP treatments had greater (P < 0.01) L* values, ANT was intermediate, and BA had the lowest (P < 0.01) L* values. The NT and IMP treatments had higher (P < 0.01) a* and b* values compared with ANT, which were higher (P < 0.01) than BA. Steaks from implanted steers (IMP and BA) tended (P ≤ 0.067) to exhibit higher a* and b* than steaks from nonimplanted steers. Cattle in the NT and ANT treatments produced steaks with increased (P < 0.01) crude fat percentage compared with the IMP and BA treatments, which were similar (P > 0.05). Percent moisture of NT steaks was lower (P < 0.01) than all other treatments, ANT was intermediate, and IMP and BA were similar (P > 0.05) and had the highest (P < 0.01) moisture content. Cook loss tended to be greater (P = 0.088) for implanted steers (IMP and BA) compared to nonimplanted steers (NT and ANT). Steaks from NT and ANT treatments were more tender (P < 0.05) than IMP and BA, which were similar (P > 0.05). Thus, WBSF was lower (P < 0.001) in nonimplanted than implanted steaks. Expression of calpastatin was increased (P ≤ 0.025) in ANT and BA treatments, and there was a tendency for expression of calpain-2 to be increased (P = 0.081) in ANT compared to NT. These results suggest that production systems with limited use of growth promoting technology produced strip loins with more crude fat, less moisture and cook loss, and improved tenderness.

Meat Quality of Nellore Young Bulls-Effects of Different Days on Feed and Zilpaterol Hydrochloride Supplementation

Ninety-six Nellore young bulls were fed (90 or 117 day) diets containing ZH (8.33 mg/kg) for 0, 20, 30, or 40 days to evaluate the effects of days on feed (DOF) and length of zilpaterol hydrochloride (ZH) supplementation on meat quality. At the end of feeding period, animals were slaughtered, and samples of the Longissimus muscle were collected to evaluate the chemical composition, fatty acid profile, color stability, shear force, and sensory profile. DOF did not affect chemical composition, shear force, sensory tenderness, and most of fatty acids; however, animals fed for 90 d had lower redness (p < 0.01), sustained juiciness (p < 0.01), and more flavor (p = 0.03) than those fed for 117 d. The ZH supplementation decreased lipid content and redness (p < 0.01), initial and sustained tenderness (p < 0.01), initial and sustained juiciness (p < 0.01), but increased protein (p < 0.01) and shear force (p < 0.01) as compared to non-supplemented animals. The ZH supplementation increased total PUFA, c9,c12-18:2, and 20:4-n6, and decreased c9-20:1 (p < 0.05). Feeding ZH impairs meat quality attributes of Nellore young bulls, regardless of duration of supplementation, while DOF has a small effect on meat quality properties.

Drivers of Consumer Liking for Beef, Pork, and Lamb: A Review

Tenderness, juiciness, and flavor have been associated with consumer acceptance of beef, lamb, and pork. Drivers of consumer liking are interrelated across these species, but there are differences in consumer preferences. Animal age, animal diet, and subsequent marbling impact consumer liking across species. For beef, consumer research prior to the 1990s showed that tenderness was the main driver of liking. Consumer tenderness and juiciness liking are highly correlated. More recent research has shown that as overall tenderness improved and tenderness variation decreased, flavor has become a more important driver of beef consumer liking. Flavor is affected by consumer preparation methods, familiarity with different flavor presentations, and animal production systems. Animal diet impacts consumer perception of beef tenderness and flavor, especially when comparing forage-fed versus grain-fed beef. Flavor preferences vary across countries more so than preferences for beef based on consumer tenderness preferences and are most likely influenced by the consumption of locally produced beef and the flavor-derived type of beef traditionally consumed. Drivers of pork consumer liking have been shown to be affected by pH, color, water holding capacity, animal diet, and the presence of boar taint compounds. While tenderness and juiciness continue to be drivers of consumer liking for pork, flavor, as impacted by animal diet and the presence of boar taint compounds, continues to be a driver for consumer liking. For lamb, the flavor, as affected by diet, and animal age continue to be the main drivers of consumer liking. Lamb consumers vary across countries based on the level of consumption and preferences for flavor based on cultural effects and production practices.

Palatability of Beef Strip Loin Steaks Representing Various Marbling and Maturity Levels from Grain-Fed Beef

This study compared palatability traits of beef strip loin steaks with varying marbling scores from young and mature grain-fed beef. Strip loins (n = 150) were selected from grain fed cattle representing ten treatments with the following USDA marbling scores: Slightly Abundant or greater (SLAB+), Moderate or Modest (MD/MT), Small (SM), Slight (SL), and Traces or Practically Devoid (TR/PD) from young “A” maturity carcasses (Y) and mature “C” or greater maturity carcasses (M). Subprimals were fabricated into 2.5-cm steaks at 21 d postmortem and stored frozen until further analysis. Consumer (n = 120) sensory panelists evaluated cooked steaks for tenderness, juiciness, flavor liking, and overall liking. Trained panelists (n = 15 sessions) evaluated each sample for initial and sustained juiciness, initial and sustained tenderness, flavor intensity, and off-flavor intensity. For all traits, consumer and trained panelists’ scores generally decreased with decreasing marbling score, regardless of maturity. According to consumers, maturity had no effect on juiciness or flavor liking within each marbling score, except flavor liking of SLAB+ was greater (P < 0.05) for young than mature carcasses. Conversely, young carcasses had greater tenderness scores than mature within all marbling categories except SM, which translated to greater overall liking of MD/MT, SL, and TR/PD of young compared to their mature counterparts (P < 0.05). Trained panelists detected very few differences between young and mature samples within their respective marbling score; however, M-MD/MT had lower initial and sustained tenderness coupled with greater off-flavor intensity than Y-MD/MT (P < 0.05). Mature samples with SLAB+ and MD/MT marbling were rated greater than or equal to Y-SM for all traits, indicating the presence of marbling from feeding a grain diet prior to harvest may elicit a similar eating experience to young beef by offsetting negative palatability traits often associated with mature beef.

Influence of Production Practice Information on Consumer Eating Quality Ratings of Beef Top Loin Steaks

The purpose of this study was to identify if consumers’ palatability scores of beef top loin steaks were affected by disclosing production practices or brands related to each product. Strip loins were selected to represent 5 treatments: Grain-Fed Natural (Natural), Certified Angus Beef (CAB), Local Grass Fed (Grass), USDA Select (Conventional), and USDA Certified Organic (Organic). Two separate experiments were conducted (n = 120/experiment). In Experiment 1 and 2, panelists received the 5 treatment samples in a standard blind testing format in segment 1 (S1). In the second segment (S2) of Experiment 1, short descriptions were read aloud to participants before receiving each of their 5 samples, but all samples were actually USDA Select (false disclosure). In the second segment of Experiment 2, treatment descriptions were provided that matched the 5 treatments samples (true disclosure). When consumers evaluated samples in S1, they rated the Natural and CAB samples more tender and juicier (P < 0.05) than the other 3 treatments, and Organic was the least tender. Flavor and overall liking were greater (P < 0.05) for Natural and CAB steaks, while Conventional was intermediate, and flavor and overall liking were lowest for Grass and Organic (P < 0.05). When consumers received Select samples representing the 5 treatments, false disclosure decreased tenderness and juiciness of Natural, increased flavor liking of CAB, and increased tenderness, flavor liking, and overall liking of Organic (P < 0.05). True treatment disclosure increased flavor liking and overall liking of CAB and Grass, increased overall liking of Natural, and decreased juiciness of Conventional (P < 0.05). These results indicate consumers’ perception of eating quality can be influenced by quality differentiated brand names and labeling claims, particularly claims related to production practices.

Palatability and Biochemical Factors of Beef from Mature Cattle Finished on a Concentrate Diet Prior to Harvest

The objective of this study was to investigate the influence of grain-finishing on mature beef palatability. Beef strip loins (n = 15 per treatment) from 2 marbling score groups [Slight (SL) and Traces/Practically Devoid (TR/PD)] and 3 carcass types [young fed (YF), mature fed (MF), and mature unfed (MU)] were collected. Young fed and MF cattle were grain-finished prior to harvest, whereas, beef from MU cattle were not identified as being grain-finished prior to harvest. Consumer and trained sensory panels evaluated steaks for palatability characteristics. Additionally, Warner-Bratzler shear force (WBSF), collagen solubility, sarcomere length, and volatile compounds were evaluated. Consumer ratings were not influenced (P > 0.05) by an interaction of main effects. Slight samples were greater (P < 0.05) than TR/PD samples for tenderness, juiciness, flavor, and overall like. Trained panelists rated SL samples more tender (P < 0.01) than TR/PD samples. Additionally, YF and MU steaks were the most and least tender (P < 0.01), respectively. No differences (P > 0.05) were observed among SL samples for beef flavor, beef flavor intensity, or off-flavor intensity due to carcass type. However, TR/PD-MF and MU steaks had more intense (P < 0.01) off-flavors. Steaks from YF and MF carcasses had lower (P < 0.01) WBSF values than steaks from MU carcasses. Percentage of heat soluble collagen was greatest (P < 0.01) in YF carcasses. Among SL treatments, sarcomere length was not affected (P > 0.05) by carcass type; however, MF and MU carcasses with TR/PD marbling scores had shorter (P < 0.05) sarcomeres than YF carcasses. Various volatile compounds were influenced (P < 0.05) by treatment and showed relationships with sensory ratings. Improvements in palatability were observed due to grain-finishing mature cattle, suggesting an adequate degree of marbling could offset negative palatability traits typically associated with beef from mature cattle.

Ionophore strategy affects growth performance and carcass characteristics in feedlot steers

One hundred ninety-two steers (BW = 354 ± 23.5 kg) were used in a randomized block design to evaluate the effects of ionophore and ractopamine hydrochloride (RH) supplementation strategies on performance and carcass characteristics. Twelve pens of 4 steers were assigned to each of the following treatments: unsupplemented control (CON), laidlomycin propionate (12.1 mg/kg DM) with or without RH (LPRH and LP, respectively), and monensin sodium (36.4 mg/kg DM) with RH (MSRH). Steers were fed for 151 d, of which respective treatments received RH (Actogain; Zoetis, Florham Park, NJ) at a rate of 300 mg/(animal · d) for the final 32 d. Laidlomycin was removed from the LPRH treatment during this period, as no combination feeding has been approved. Upon harvest, carcass data were collected by trained personnel, and subsequent analysis of the LM was conducted to estimate tenderness using Warner-Bratzler shear force (WBSF). Prior to RH supplementation, both LP and LPRH had greater ADG ( ≤ 0.02) and G:F ( < 0.01) than CON, whereas MSRH was intermediate. During the final 32 d, MSRH improved G:F ( ≤ 0.02) compared to all other treatments and tended to increase ADG over unsupplemented controls ( = 0.05). Cattle receiving LP without RH had significantly greater BW at d 151 than CON ( = 0.02), whereas both RH treatments tended to improve final BW ( ≤ 0.09). Ionophores improved ADG ( ≤ 0.03) and G:F ( < 0.01) for the entire feeding period, and although LP-supplemented cattle had greater DMI for the final 32 d than both RH treatments ( ≤ 0.01), intakes for the 151-d trial were similar among treatments. Carcass weights were greater ( = 0.04) in cattle fed LP with no RH than CON, where cattle yielded an average of 12 kg more HCW. Ractopamine increased LM area in MSRH-supplemented cattle ( = 0.03) and tended to increase LM area for steers receiving LPRH ( = 0.07). Longissimus steaks of MSRH-supplemented cattle had greater WBSF values than CON ( = 0.04) after 7 d of postmortem aging and greater WBSF values than LPRH steaks after 28 d ( = 0.03). All other carcass and WBSF measurements were similar among treatments. The results of this study indicate that LP supplementation without RH may yield a performance similar to and carcass responses associated with the administration of a β-agonist. These results also suggest that performance and carcass characteristics for cattle fed LP are similar to those of cattle fed monensin throughout the feeding period.

Beef flavor: a review from chemistry to consumer

This paper briefly reviews research that describes the sensation, generation and consumer acceptance of beef flavor. Humans sense the five basic tastes in their taste buds, and receptors in the nasal and sinus cavities sense aromas. Additionally, trigeminal senses such as metallic and astringent are sensed in the oral and nasal cavities and can have an effect on the flavor of beef. Flavors are generated from a complex interaction of tastes, tactile senses and aromas taken collectively throughout the tongue, nasal, sinus and oral cavities. Cooking beef generates compounds that contribute to these senses and result in beef flavor, and the factors that are involved in the cookery process determine the amount and type of these compounds and therefore the flavor generated. A low-heat, slow cooking method generates primarily lipid degradation products, while high-heat, fast cookery generates more Maillard reaction products. The science of consumer acceptance, cluster analyses and drawing relationships among all flavor determinants is a relatively new discipline in beef flavor. Consumers rate beef that has lipid degradation products generated from a low degree of doneness and Maillard flavor products from fast, hot cookery the highest in overall liking, and current research has shown that strong relationships exist between beef flavor and consumer acceptability, even more so than juiciness or tenderness.