Grain-finished Cattle Research Articles

Effects of Chilling Duration on Marbling Score of Beef Carcasses

Two hundred and nine beef carcasses (body weight of 361±53 kg) from crossbred, grain-finished cattle were harvested in a commercial abattoir and subjected to continuous chilling for 96 h at 0°C to 3°C in a commercial hot box with a wind speed of 3.1 m/s and 153 lux of fluorescent light. At 24, 48, 72, and 96 h, the carcasses were analyzed for fatty acid composition,marbling score, pH, shrinkage, color, and aerobic plate count (n = 50). Carcasses reached 3°C after 12 to 16 h of chilling. There were minimal changes in shrinkage among time point (−0.4% to 1.2%; P ≤ 0.002), pH (5.56 to 5.69; P ≤ 0.001), and aerobic plate count (0.1 to 0.7 log; P < 0.001). Initial 24-h grading by a USDA grader revealed a grade composition of 21.1% Slight (n = 44), 34.0% Small (n = 71), 17.2% Modest (n = 37), 17.7% Moderate (n = 36), and 10.1% Slightly Abundant (n = 21). With a marbling score in numeric values between 200 (Practically Devoid00) and 1100 (Abundant00), carcasses that had Small or greater marbling score at 24 h experienced a decrease of 34 to 60 points after 96 h of chilling (P ≤ 0.042). Comparatively, the marbling scores of the Slight carcasses increased from 442 points at 24 h to 469 points at 96 h. Moreover, Slight carcasses had a greater percentage of polyunsaturated fatty acids (P < 0.001). Results indicate that chilling for 96 h increases the marbling score of USDA Select but has minimal impacts on the marbling score of greater USDA quality grades.

Effects of Finishing Diet and Packaging on Longissimus Dorsi Color

ObjectivesMeat color is extremely influential in purchasing decisions as consumers associate a bright-red color with freshness. The type of finishing diet can influence beef color. Previous studies have shown that grass-finished cattle have darker muscle color than grain-finished cattle. With the use of modified atmospheric packaging (MAP), beef purveyors are able to vary the gas compositions within a package and enhance beef color. However, limited studies have determined the effects of modified atmospheric packaging on grass-finished beef color. The objective of this study was to determine how finishing diet and packaging type affects the color of the longissimus dorsi (LD) muscle.Materials and MethodsDuring the stocker period, all of the cattle were on a forage diet. Cattle were then randomly assigned to either a conventional grain-based diet or an alfalfa pasture diet for finishing. Both conventionally and pasture-finished cattle were fed for 91 d. Cattle were slaughtered on the same day at a commercial beef processing facility under normal conditions and chilled for approximately 30 h. After grading, one strip loin from each carcass was collected and transported to Oklahoma State University. At 11 d postmortem, one steak (n = 60) from each strip loin was vacuum packaged and randomly assigned to display. Those steaks were then randomly assigned to PVC, HiOx-MAP (80% oxygen and 20% carbon dioxide), or CO-MAP (0.4% carbon monoxide, 69.5% nitrogen, and 30% carbon dioxide) packaging and were displayed under retail conditions for 5 d. Muscle darkening (MD), muscle color (MC), and surface discoloration (SD) were all analyzed by a trained panel (n = 6). MD was evaluated only on d 0 and MC and SD were scored once every 24 h for 0, 1, 2, 3, and 4 d. Lipid oxidation was measured by thiobarbituric acid reactive substances (TBARS) assay on d 4. Data were analyzed using the Mixed Procedure of SAS.ResultsThere was a significant display day by finishing diet by packaging interaction (P < 0.05) for muscle color and surface discoloration. There was also a significant finishing diet by packaging interaction (P < 0.05) for muscle darkening. Steaks packaged in HiOx-MAP remained the most stable in color and the brightest cherry-red colored throughout display time (P < 0.05) compared with other packaging types. PVC was the most discolored (P < 0.05) on d 3 and 4 when compared to HiOx-MAP and CO-MAP with the grain-finished PVC packaged steaks showing the most discoloration on d 4. Pasture-finished steaks packaged in CO-MAP displayed the darkest colored muscle (P < 0.05) on d 0. Steaks packaged in PVC had a higher amount of lipid oxidation (P < 0.05) compared with other packaging types.ConclusionThese results indicate that HiOx-MAP more effectively maintains the desired beef color of bright cherry-red for pasture-finished beef. The results also indicate that the use of appropriate packaging type can minimize the losses due to discoloration of steaks from either grain or grass-finished beef.

Effects of Finishing Diet and Packaging on Longissimus Dorsi Color

ObjectivesMeat color is extremely influential in purchasing decisions as consumers associate a bright-red color with freshness. The type of finishing diet can influence beef color. Previous studies have shown that grass-finished cattle have darker muscle color than grain-finished cattle. With the use of modified atmospheric packaging (MAP), beef purveyors are able to vary the gas compositions within a package and enhance beef color. However, limited studies have determined the effects of modified atmospheric packaging on grass-finished beef color. The objective of this study was to determine how finishing diet and packaging type affects the color of the longissimus dorsi (LD) muscle.Materials and MethodsDuring the stocker period, all of the cattle were on a forage diet. Cattle were then randomly assigned to either a conventional grain-based diet or an alfalfa pasture diet for finishing. Both conventionally and pasture-finished cattle were fed for 91 d. Cattle were slaughtered on the same day at a commercial beef processing facility under normal conditions and chilled for approximately 30 h. After grading, one strip loin from each carcass was collected and transported to Oklahoma State University. At 11 d postmortem, one steak (n = 60) from each strip loin was vacuum packaged and randomly assigned to display. Those steaks were then randomly assigned to PVC, HiOx-MAP (80% oxygen and 20% carbon dioxide), or CO-MAP (0.4% carbon monoxide, 69.5% nitrogen, and 30% carbon dioxide) packaging and were displayed under retail conditions for 5 d. Muscle darkening (MD), muscle color (MC), and surface discoloration (SD) were all analyzed by a trained panel (n = 6). MD was evaluated only on d 0 and MC and SD were scored once every 24 h for 0, 1, 2, 3, and 4 d. Lipid oxidation was measured by thiobarbituric acid reactive substances (TBARS) assay on d 4. Data were analyzed using the Mixed Procedure of SAS.ResultsThere was a significant display day by finishing diet by packaging interaction (P < 0.05) for muscle color and surface discoloration. There was also a significant finishing diet by packaging interaction (P < 0.05) for muscle darkening. Steaks packaged in HiOx-MAP remained the most stable in color and the brightest cherry-red colored throughout display time (P < 0.05) compared with other packaging types. PVC was the most discolored (P < 0.05) on d 3 and 4 when compared to HiOx-MAP and CO-MAP with the grain-finished PVC packaged steaks showing the most discoloration on d 4. Pasture-finished steaks packaged in CO-MAP displayed the darkest colored muscle (P < 0.05) on d 0. Steaks packaged in PVC had a higher amount of lipid oxidation (P < 0.05) compared with other packaging types.ConclusionThese results indicate that HiOx-MAP more effectively maintains the desired beef color of bright cherry-red for pasture-finished beef. The results also indicate that the use of appropriate packaging type can minimize the losses due to discoloration of steaks from either grain or grass-finished beef.

Comparing Honduran and United States Consumers’ Sensory Perceptions of Honduran and U.S. Beef Loin Steaks

The objective of this study was to compare the eating quality characteristics of beef from the United States and Honduras and to assess the willingness of Honduran and U.S. consumers to pay for these products. All U.S. sourced strip loins from grain-finished cattle, aged 21 d, were selected to equally represent USDA Select (SEL; n = 6) and upper 2/3 (Top) Choice (TC; n = 6) quality grades. Additionally, strip loins (n = 6) from Honduran grass-finished (HGRASS) cattle and grain-finished (HGRAIN) cattle (n = 6) were collected from a commercial abattoir in Siguatepeque, Honduras and aged 21 d. Samples were evaluated on 8-point hedonic scales for flavor, tenderness, juiciness, and overall liking by 240 consumers in each country. Consumers indicated if each trait was acceptable, and willingness to pay for each sample was rated in U.S. dollars (or the Honduran Lempiras equivalent): $0, 3, 6, and 10 per 0.45 kg. Chemical composition and Warner-Bratzler shear force (WBSF) were also determined. The TC had greater (P &lt; 0.05) fat percentage than SEL and HGRASS, but did not differ (P &gt; 0.05) from HGRAIN. The HGRAIN had greater WBSF values than TC and SEL, which did not differ (P &gt; 0.05); however, HGRASS was similar (P &gt; 0.05) to all other treatments. The TC had greater tenderness and flavor liking scores (P &lt; 0.05) than all other treatments, followed by SEL, HGRASS, and HGRAIN, with a significant difference between each treatment. Honduran consumers assigned greater ratings for tenderness and flavor liking when compared to U.S. consumers. The lowest rated treatment in both countries was Honduran grain-finished followed by Honduran grass-finished. Consumers in Honduras were willing to pay more for samples when compared to U.S. consumers. Consumers were also willing to pay a premium for products with greater palatability, regardless of the country of origin.

Comparing Honduran and United States Consumers’ Sensory Perceptions of Honduran and U.S. Beef Loin Steaks

The objective of this study was to compare the eating quality characteristics of beef from the United States and Honduras and to assess the willingness of Honduran and U.S. consumers to pay for these products. All U.S. sourced strip loins from grain-finished cattle, aged 21 d, were selected to equally represent USDA Select (SEL; n = 6) and upper 2/3 (Top) Choice (TC; n = 6) quality grades. Additionally, strip loins (n = 6) from Honduran grass-finished (HGRASS) cattle and grain-finished (HGRAIN) cattle (n = 6) were collected from a commercial abattoir in Siguatepeque, Honduras and aged 21 d. Samples were evaluated on 8-point hedonic scales for flavor, tenderness, juiciness, and overall liking by 240 consumers in each country. Consumers indicated if each trait was acceptable, and willingness to pay for each sample was rated in U.S. dollars (or the Honduran Lempiras equivalent): $0, 3, 6, and 10 per 0.45 kg. Chemical composition and Warner-Bratzler shear force (WBSF) were also determined. The TC had greater (P 0.05) from HGRAIN. The HGRAIN had greater WBSF values than TC and SEL, which did not differ (P > 0.05); however, HGRASS was similar (P > 0.05) to all other treatments. The TC had greater tenderness and flavor liking scores (P < 0.05) than all other treatments, followed by SEL, HGRASS, and HGRAIN, with a significant difference between each treatment. Honduran consumers assigned greater ratings for tenderness and flavor liking when compared to U.S. consumers. The lowest rated treatment in both countries was Honduran grain-finished followed by Honduran grass-finished. Consumers in Honduras were willing to pay more for samples when compared to U.S. consumers. Consumers were also willing to pay a premium for products with greater palatability, regardless of the country of origin.

Resource use and greenhouse gas emissions from grain-finishing beef cattle in seven Australian feedlots: a life cycle assessment

Grain finishing of cattle has become increasingly common in Australia over the past 30 years. However, interest in the associated environmental impacts and resource use is increasing and requires detailed analysis. In this study we conducted a life cycle assessment (LCA) to investigate impacts of the grain-finishing stage for cattle in seven feedlots in eastern Australia, with a particular focus on the feedlot stage, including the impacts from producing the ration, feedlot operations, transport, and livestock emissions while cattle are in the feedlot (gate-to-gate). The functional unit was 1 kg of liveweight gain (LWG) for the feedlot stage and results are included for the full supply chain (cradle-to-gate), reported per kilogram of liveweight (LW) at the point of slaughter. Three classes of cattle produced for different markets were studied: short-fed domestic market (55–80 days on feed), mid-fed export (108–164 days on feed) and long-fed export (&gt;300 days on feed). In the feedlot stage, mean fresh water consumption was found to vary from 171.9 to 672.6 L/kg LWG and mean stress-weighted water use ranged from 100.9 to 193.2 water stress index eq. L/kg LWG. Irrigation contributed 57–91% of total fresh water consumption with differences mainly related to the availability of irrigation water near the feedlot and the use of irrigated feed inputs in rations. Mean fossil energy demand ranged from 16.5 to 34.2 MJ lower heating values/kg LWG and arable land occupation from 18.7 to 40.5 m2/kg LWG in the feedlot stage. Mean greenhouse gas (GHG) emissions in the feedlot stage ranged from 4.6 to 9.5 kg CO2-e/kg LWG (excluding land use and direct land-use change emissions). Emissions were dominated by enteric methane and contributions from the production, transport and milling of feed inputs. Linear regression analysis showed that the feed conversion ratio was able to explain &gt;86% of the variation in GHG intensity and energy demand. The feedlot stage contributed between 26% and 44% of total slaughter weight for the classes of cattle fed, whereas the contribution of this phase to resource use varied from 4% to 96% showing impacts from the finishing phase varied considerably, compared with the breeding and backgrounding. GHG emissions and total land occupation per kilogram of LWG during the grain finishing phase were lower than emissions from breeding and backgrounding, resulting in lower life-time emissions for grain-finished cattle compared with grass finishing.

Effects of USDA carcass maturity on sensory attributes of beef produced by grain-finished steers and heifers classified as less than 30 months old using dentition1

This study compared sensory properties of LM steaks from A maturity and B maturity or older carcasses that were produced by grain-finished steers and heifers classified as less than 30 mo old at the time of slaughter using dentition. Carcasses were selected to represent 2 maturity groups and 3 marbling categories within each maturity group, resulting in 6 maturity × marbling subclasses, each subclass consisting of 75 carcasses. Maturity groups consisted of carcasses classified by USDA graders as either A(00) to A(99) overall (A) maturity or B(00) to C(99) overall (B-C) maturity; marbling categories consisted of carcasses with instrument marbling scores of Slight (SL), Small (SM), or Modest(00) or greater (MT+). Carcasses were selected in pairs so that each carcass chosen to represent the B-C maturity group was paired with an A maturity carcass of the same sex and marbling score (± 30 marbling units). Strip loin (LM) steaks were obtained from both sides of each carcass. After a 14-d aging period, 1 LM steak was measured for Warner-Bratzler shear force (WBSF) and slice shear force (SSF), whereas the other LM steak was used for sensory analysis by a trained descriptive attribute panel. No differences (P > 0.05) in WBSF, SSF, or sensory panel ratings for tenderness, juiciness, or flavor were detected between LM steaks from carcasses classified as A maturity and steaks from B-C maturity carcasses. However, marbling categories effectively stratified carcasses (MT+ > SM > SL) according to differences (P < 0.0001) in LM tenderness, juiciness, meaty/brothy flavor, and buttery/beef fat flavor. Increased marbling also was associated with lesser (P < 0.01) intensities of bloody/serumy and livery/organy flavors and reduced (P < 0.01) values for WBSF and SSF. Of the traits tested, only bloody/serumy flavor was affected (P < 0.05) by the maturity × marbling interaction. Interaction means showed that LM steaks from B-C maturity carcasses with SL marbling had a less intense bloody/serumy flavor than did steaks from A maturity carcasses with SL marbling. Results of this study suggest that, when applied to carcasses from grain-finished cattle whose dental ages are less than 30 mo old at the time of slaughter, USDA quality grades would be no less effective in identifying eating quality differences if the A and B-C maturity groups were combined and quality grades were assigned using only marbling.

Prostaglandin E2 production in mice is reduced by consumption of range-fed sources of red meat

Many view bison as a healthful alternative to other red meat sources, and as a way to decrease health risks, they associate it with meat consumption. Using mice as a model for immune function, we hypothesized that consumption of meat from range-fed bison would decrease prostaglandin (PG) E₂ and alter prostacyclin (PGI₂) release upon immune challenge when compared with mice fed meat from grain-finished bison, range-fed beef, feedlot steers, free-ranging elk, or chicken breast. After 2 weeks on an experimental diet and inflammatory stimulation, mouse peritoneal macrophage was isolated and analyzed in 12 animals per diet. Peritoneal cell arachidonic acid increased in response to a chicken-based diet (P < .05), which was likely attributable to higher arachidonic acid intake. Release of PGE₂ was lowest in mice consuming meat of range-fed beef, range-fed bison, and elk but was highest with meat of grain-finished beef and intermediate in mice fed chicken (P < .05). Mice fed elk meat had the greatest PGI₂, whereas PGI₂ was decreased in mice fed meat of either range bison, range beef, or chicken (P < .05) and intermediate in mice fed meat of steers or bison finished in a feedlot. We conclude that consumption of meats characteristic of range-fed ruminants or wild ungulates supports reduced PGE₂ and greater PGI₂ synthesis, indicating potentially greater immune health and lower blood clotting potential than meat from grain-finished cattle or bison in this model system.

Disparity of dietary effects on collagen characteristics and toughness between two beef muscles

Manipulation of growth rate and/or diet has been shown to affect protein turnover and may be used to improve beef quality. This trial was conducted to evaluate the effects of average daily gain (ADG) and diet on animal performance, collagen characteristics and beef quality of two different muscles; longissimus dorsi (LD) and semitendinosus (ST). Seventy six Hereford and Angus steers were assigned to three dietary management regimens for finishing: high grain diet based on corn (n=28), alfalfa pasture (n=22) and grass pasture (n=26). Average daily gains were greater (P<0.001) in Herefords vs. Angus and for corn- vs. pasture finished cattle. Overall, total collagen content was greater (P<0.001) and the percentage of total collagen that was heat soluble was lower (P<0.0001) for ST than for LD muscle. The lowest (P<0.05) values for both total and heat soluble collagens were found in animals finished on corn. WBSF values for LD were greater (P<0.01) in grass-fed vs. alfalfa- and grain-finished cattle while there was no difference in WBSF values for ST between grass- and corn-fed animals. No correlation between ADG and WBSF was observed for any muscle. ADG was not correlated with collagen solubility in ST, but was correlated (P<0.05) with collagen solubility in LD. A key finding is that growth rate affected heat soluble collagen in the two muscles to a different extent. In conclusion, this study shows that different feeding strategies may not influence the tenderness of all muscles in a similar way.

Variation in Flavor and Textural Descriptions of Cooked Steaks from Bovine m. longissimus thoracis et lumborum from Different Production and Aging Regimes

: Free choice profiling (FCP) and generalized Procrustes analysis (GPA) were used to assess flavor differences in cooked bovine m. longissimus thoracis et lumborum (LTL) steaks sourced wholesale or from steers fed the same diet. Wholesale steaks were from LTL muscles that were either unaged or aged for 93 d with high or low visible marbling from old and young grass- and grain-finished cattle. The GPA of this sensory data showed that the 1st dimension contrasted grass- and grain-finished beef and accounted for 44.1% of the total variance, whereas the 2nd dimension contrasted unaged and aged beef and accounted for 22.9% of the variance. GPA was also used to assess flavor variation in cooked LTL steaks aged 4 or 14 d postmortem from 10 steers finished on the same diet, and the 1st 2 dimensions accounted for 39% of the total variance. Univariate analysis of beef aroma, flavor intensity, tenderness, and juiciness showed only tenderness increased with aging (P= 0.041) and Duncan's multiple comparison test on all FCP data indicated that aging beef up to 14 d shifted beef sensory characteristics toward increased tenderness, juiciness, and fatty flavor. The results of these studies showed that distinct flavors exist in beef from cattle finished in different production systems and that there is less variation in the flavor of beef from steers produced on the same farm than in beef available for general retail.

Breed differences in the fatty acid composition of subcutaneous and intramuscular lipid of early and late maturing, grain-finished cattle

Fatty acid composition was measured in lipid extracted from adipose tissue and muscle collected at slaughter from 6 groups of crossbred cattle of about 2 years of age, grain-finished in a feedlot. The cattle ranged in biological type from late to early maturing. They were progeny of the following crosses: Charolais x (Simmental.Hereford), Simmental x (Simmental.Hereford), Charolais x (Jersey.Hereford), Hereford x Hereford, Hereford x (Jersey.Hereford), Jersey x Hereford. The fat content of muscle from the leanest late-maturing cross was 5.2% rising to 10.4% in the fattest early-maturing cross. There was no significant difference in the fatty acid composition of subcutaneous fat between the 6 crosses, but there was in the concentration of some of the fatty acids of intramuscular lipid. The latter was due on one hand to the increased deposition of neutral lipid in early-maturing animals and on the other to a higher proportion of polyunsaturated fatty acids in membrane phospholipid in late-maturing animals. The proportions of the monounsaturated fatty acids palmitoleic (C16:l) and oleic (C18:l) were higher in the early-maturing Jersey x Hereford crosses than in straight-bred Herefords or the other crosses, but only in the C16:l values was there a significant difference between breeds. There was also a significant difference between breeds in the sum of monounsaturates and the sum of polyunsaturates in intramuscular fat. The Jersey crosses had the highest level of monounsaturates and the lowest level of polyunsaturates. Intramuscular phospholipid was examined in the 2 breeds that were the most divergent in terms of intramuscular fat content, the Charolais x (Simmental.Hereford) and the Jersey x Hereford. The latter had significantly higher C16:l values and significantly lower C18:2 and polyunsaturate fatty acid values. The experiment demonstrated that breed differences occurred in fatty acid composition of muscle total lipid and phospholipid. The differences are of significance in human health and in identifying maturity breed-types of cattle.

Influence of diet on growth rate and carcass composition of steers differing in frame size and muscle thickness.

One hundred seventy-three steer calves, selected at weaning to represent USDA classifications for frame size (Large, L; Medium, M; Small, S) and muscle thickness (No. 1, No. 2, No. 3), were assigned to three finishing diets (grain, 3.03 Mcal ME/kg DM; silage, 2.46 Mcal ME/kg DM; forage, 2.06 Mcal ME/kg DM), forming a 3 x 3 x 3 factorial with unequal subclass numbers. The steers were slaughtered at constant weights corresponding to their respective frame size classifications (L = 590 kg, M = 499 kg; S = 408 kg). Individual live weights were recorded every 28 d during finishing and, following slaughter, one side of each carcass was dissected into muscle, bone and fat. Diet interacted with frame size to affect growth rate. Frame-related differences in growth rate were very pronounced among grain-fed steers (L greater than M greater than S) but became smaller in magnitude as feeding intensity was reduced. Diet also had a significant effect on percentage separable carcass fat, despite the fact that the steers were slaughtered at a similar percentage (approximately 60%) of their estimated potential mature weights. Carcasses produced by grain-finished steers were fattest, and those produced by forage-finished cattle were leanest. The comparative fatness of steers finished on silage was dependent on frame size. Within the L class, carcasses produced by silage-finished steers were comparatively lean and were similar in fatness to carcasses produced by forage-finished cattle. Conversely, S steers finished on silage produced carcasses that were comparable in fatness to carcasses from grain-finished cattle. Frame-related differences in percentage carcass fat were significant only within the silage treatment group (S greater than L). Differences in carcass muscle-to-bone ratio were directionally consistent with visually discernible differences in feeder cattle muscling (No. 1 greater than No. 2 greater than No. 3). The effects of muscle thickness on muscle-to-bone ratio were most pronounced within the L class.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of Feeding Cooked Ground Beef on Plasma Lipid and Apolipoprotein Concentrations in Male Turkeys

Two experiments with male turkeys were designed to study the effects of eating cooked ground beef on plasma lipid and lipoprotein levels. In both experiments, cooked ground beef from forage-finished cattle (F-Bf) and grain-finished cattle (G-Bf) were added at an average of 28.1 and 34.5 g of beef per 100 g of ration in order to provide 40% of the protein requirement. The experimental diets formulated to be isocaloric and isonitrogenous were: 1) basal diet (negative control) in which soybean meal and corn oil served as protein and fat sources, respectively; 2) basal plus crystalline cholesterol (positive control) incorporated at 1 and 2% of the diet in trials 1 and 2, respectively; 3) basal plus F-Bf; 4) basal plus G-Bf. The polyunsaturated to saturated fat ratio averaged 3.45 for diets 1 and 2 and 0.17 for diets 3 and 4, respectively. At 16 weeks, consumption of diets 3 and 4 elevated (P < 0.05) plasma triglyceride levels and phospholipid levels (trial 1). In trial 2, only diet 4 elevated (P < 0.05) plasma phospholipid levels. In both trials, the beef diets did not significantly elevate plasma cholesterol and high density lipoprotein (HDL) cholesterol levels above the basal diet. However, the major apoprotein in the HDL fraction, apolipoprotein A-I (apoA-I), was increased (P < 0.05) in the plasma of male turkeys fed the G-Bf diet in both trials and F-Bf diet in trial 1. Plasma apolipoprotein B (apoB), primarily found in low density lipoproteins (LDL), was increased (P < 0.05) in one of the two trials by the inclusion of beef in the diet. There were no significant differences in plasma cholesterol, HDL-cholesterol, apoA-I and apoB levels between the types of beef (F-Bf vs. G-Bf).