Composition and estimation of intramuscular and subcutaneous fatty acid composition in Spanish young bulls

Sixty Pirenaica yearling intact bulls were raised and slaughtered at 519±50kg live weight and 371±18 days of age. Fatty acid composition of intramuscular lipids in longissimus dorsi muscle and subcutaneous fat were determined by capillary gas chromatography. Carcass conformation and fatness, carcass weight, ether extractable intramuscular fat percentage, marbling, dorsal fat thickness, and ultrasonic parameters were recorded to study the relationship between these traits and fatty acid profile. Lipids of subcutaneous adipose tissue had higher monounsaturated fatty acids (MUFA) percentage (49% vs. 33%) but lower saturated fatty acids (SFA) (51% vs. 46%) and polyunsaturated fatty acids (PUFA) (16% vs. 5%) percentages than intramuscular fat depots (p<0.001). Fatter carcasses had higher MUFA percentage and lower PUFA percentage (p<0.01) in intramuscular fat. Carcass weight and conformation would contribute to explain the fatty acid profile of subcutaneous fat (p<0.05). Ultrasound readings reflected the effect of fatness on fat composition.     

National Beef Market Basket Survey - 2006: External fat thickness measurements and separable component determinations for beef from US retail establishments

A market basket survey for beef retail cut composition at the retail level (four stores each from two chains in each city) was conducted in 11 US cities from January to March 2006. Beef cuts (n=17,495) were measured for external fat thickness with cuts from the chuck (0.05cm), round (0.05cm), and miscellaneous (0.04cm) having less (P<0.05) fat than cuts from the loin (0.11cm) and rib (0.11cm). Beef cuts (n=1327) were separated physically into separable components with round cuts having more (P<0.05) separable lean (96.63%) than chuck cuts (86.81%) and miscellaneous cuts (86.18%), which had more (P<0.05) separable lean than loin cuts (84.53%) with rib cuts (69.34%) having the lowest (P<0.05) separable lean. Chemical fat from the separable lean differed (P<0.05) between each cut category: round cuts (3.71%), miscellaneous cuts (4.99%), loin cuts (5.60%), chuck cuts (6.90%), and rib cuts (8.61%). Ground beef samples (n=235), with declared lean/fat percentages ranging from 73/27 to 96/4, had overall chemical fat values of 13.41% and moisture values of 67.42%. This survey documents the current beef retail cut and ground beef composition, which is helpful to those who need this information for various dietary and marketing purposes.     

Prediction of beef carcass salable yield and trimmable fat using bioelectrical impedance analysis

Bioelectrical impedance technology (BIA) is capable of providing an objective method of beef carcass yield estimation with the rapidity of yield grading. Electrical resistance (Rs), reactance (Xc), impedance (I), hot carcass weight (HCW), fat thickness between the 12th and 13th ribs (FT), estimated percentage kidney, pelvic, and heart fat (KPH%), longissimus muscle area (LMA), length between electrodes (LGE) as well as three derived carcass values that included electrical volume (EVOL), reactive density (XcD), and resistive density (RsD) were determined for the carcasses of 41 commercially fed cattle. Carcasses were subsequently fabricated into salable beef products reflective of industry standards. Equations were developed to predict percentage salable carcass yield (SY%) and percentage trimmable fat (FT%). Resulting equations accounted for 81% and 84% of variation in SY% and FT%, respectively. These results indicate that BIA technology is an accurate predictor of beef carcass composition.     

Innovative wholesale carcass fabrication and retail cutting to optimize beef value

Innovations in beef carcass fabrication to improve subprimal yield, retail cut yield, and overall carcass value were evaluated. Alternating sides from 30 beef carcasses were assigned to either an innovative or conventional style of fabrication. The innovative method resulted in greater (P < 0.001) total subprimal yield and less (P < 0.001) lean trimmings from the forequarter; however, hindquarter total subprimal yield and lean trimmings were not affected (P > 0.05) by fabrication style. Value was greater for the innovative forequarter (P < 0.001) and hindquarter (P < 0.01), and total value was increased by more than US $14 per beef carcass compared to the conventional style. Selected subprimals were evaluated in retail cutting tests. In general, the innovative retail subprimals had yields equal to or greater than the conventional subprimals. Innovative carcass fabrication may allow for greater marketing options for beef cuts to improve carcass value and to offer greater retail merchandizing opportunities.     

Predicting Longissimusdorsi myoglobin oxidation in aged beef based on early post-mortem colour measurements on the carcass as a colour stability index

Sixty young bulls of the Pirenaica breed, representative of the beef production and marketing system in northern Spain, were used. The carcass grading and weight, pH at 24 h post-mortem, and objective colour measurements (CIE L^∗a^∗b^∗) were recorded on the Latissimus dorsi, Rectus abdominis and Longissimus dorsi in order to find indicators and predictors of beef colour stability (Longissimus dorsi metmyoglobin percentage on ageing for 3, 7 and 14 days) by means of early post-mortem measurements on the carcass.     

Prediction of suckling lamb carcass composition from objective and subjective carcass measurements

Correlations and regression between fatness and carcass conformation measurements and carcass tissue composition has been studied for both sexes in suckling lambs, with slaughter weights between 9 and 15 kg. Objective fat measurements showed higher correlations than subjective fat measurements, mainly with carcass fat. Conformation measurements presented greater correlations with tissues weight than with tissues proportion (r0.50). CCW was highly correlated with total muscle in the carcass (R²=0.961). Two fatness measurements (KKCF proportion and dorsal fat thickness) were included for the prediction of the muscle proportion. Furthermore, the model included other measurements, such as fore cannon bone weight and internal carcass length although they displayed very low correlation coefficients. This equation explained 64.1% of the variation of carcass muscle proportion (r.s.d.=1.532). CCW was included in the prediction equations of tissue weights, although in the fat tissue equation it appeared in the form of the carcass compactness index (CCW/L). CCW was a good predictor of the weight of carcass tissues in suckling lambs, especially for muscle. Prediction equations for tissue composition in grams were more accurate (R²0.91) than those for tissue proportion. When gender was included in all models it did not improve either accuracy or precision of the prediction.     

The relationship between the chemical composition of the carcass and the fatty acid composition of intramuscular fat and backfat of several pig breeds slaughtered at different weights

Pigs of Belgian Landrace (B), Duroc (D), Hampshire (H), and Pietrain (P) breeds were slaughtered at 90, 110 and 130 kg body weight (BW) and the carcass chemical composition and fatty acid profiles of intramuscular fat of loin and backfat were determined. The carcass of Pietrain pigs had a higher concentration of protein and less fat than of B, D and H breeds. In tissues, the PUFA:SFA ratio was lower in the heavier (130 kg BW) than in lighter pigs (90 and 110 kg BW). This feature was higher in P pigs compared with the other breeds. The backfat had a higher concentration of PUFA:SFA ratio than intramuscular fat. The PUFA n− 6:n− 3 ratio was not affected by the breed and weight of pigs, but it was lower in backfat than in longissimus muscle fat. The protein concentration in the carcass was positively related to PUFA and negatively to SFA concentration in tissues.     

Prediction of carcass composition and individual carcass cuts of Japanese Black steers

The objective of this study was to develop equations to predict carcass tissue weights and percentages and boneless carcass non-trimmed cut weights by using the cold carcass weight (CCW) and three other traits at the 6–7th rib section, which are routinely collected in carcass markets in Japan. Carcasses from 94 Japanese Black steers were used for the multiple regression analysis with a stepwise procedure and a novel Least Absolute Shrinkage and Selection Operator (LASSO). The accuracies of prediction (R²) and RMSEs for the carcass tissue and cut weights were similar between the two procedures. In contrast, LASSO appeared to be the better procedure for predicting carcass tissue percentages. The longissimus muscle area and subcutaneous fat thickness were the important predictors for the lean percentage in the stepwise procedure, and CCW was additionally selected when the LASSO procedure was used.     

Assessing beef carcass tissue weights using computed tomography spirals of primal cuts

More than 800 beef primal cuts from 44 Aberdeen Angus and Limousin-cross steers carcasses were scanned using spiral computed tomography (CT) and dissected. Thresholds for the segmentation of fat, muscle and bone in the CT spirals were estimated with the objective of assessing the weight of these tissues in the primal cuts and in the entire carcasses. Thresholds were estimated using half of the dataset (DBE) and then validated in the other half (DBV). Automatic image analysis procedures were used to assess tissue weights. The R² of the regression between primal tissue weight by dissection and CT were high in both datasets for fat (DBE, 0.89; DBV, 0.92), muscle (DBE, 0.99; DBV, 0.99) and bone (DBE, 0.95; DBV, 0.97). The estimation of total carcass tissue weights were also very accurate for the three tissues (R² values of 0.95 to 0.96), indicating that CT scanning may deliver very accurate information on beef carcass composition faster and with lower cost than physical dissection and without damaging or depreciating the primal joints.     

Influence of animal temperament and stress responsiveness on the carcass quality and beef tenderness of feedlot cattle

Three groups of steers (A, B, C) were used to study the effect of temperament (Calm, Intermediate, and Excitable) on meat quality. Temperament was based on exit velocity, pen scores, and chute scores. Temperament traits were consistent across evaluations, and values decreased (P<0.05) in magnitude over time. Increasing excitability was associated with higher (P<0.05) serum cortisol concentrations. Carcasses from cattle with calm temperaments had higher (P<0.05) 0.5h postmortem pH values than those from Intermediate and Excitable cattle (0.1 and 0.2 units, respectively). Group C Excitable steers had higher (P<0.05) WBS values than the calmer Group C steers. This trend was observed in Group A steers, although the values were not statistically different. Correlations were highest between temperament values and tenderness after 21d. Temperament influences tenderness, although the mechanism is not clear.     

The relationship between different pork carcass lean yield definitions and the market carcass value

Cutout and dissection data from 265 carcasses were used to study the impact of the lean yield definition on their ability to discriminate lean carcasses from fat carcasses. The same data were used to evaluate the relationship between the various definitions of lean yield, such as the lean yield predicted by the Destron optical probe (LYDESTRON), the saleable meat yield (SMY), the Canadian lean yield (LY2000) and the lean meat percentage (TVM), and the market carcass value. Based on the highest number of carcasses assigned to the extreme grades (leaner and fatter), the TVM had the greatest discriminating capability based on carcass leanness. The correlation coefficients obtained between market carcass value and LYDESTRON, SMY, LY2000 and TVM were 0.14, 0.54, 0.36 and 0.23, respectively. These weak correlations demonstrate that lean yield alone does not adequately explain the variation in market value between carcasses. Lean yield therefore cannot be used to estimate market value independently of the definition used.     

Comparison of stunning methods in the dissemination of central nervous system tissue on the beef carcass surface

Beef carcasses were examined to explore the effects of stunning methods on central nervous system tissue (CNST) dissemination on the surface during the slaughtering process. The frequency of occurrence of CNST contamination on four defined parts, each on the interior and exterior surfaces of the split carcass, and their level of the contamination were measured by an ELISA test. The effect of hot carcass weight was also examined. The results showed that the frequency of contamination occurrence was not affected by the stunning method. However, the penetrating captive bolt stunning method resulted in a higher level of CNST contamination than non-penetrating sledge-hammer stunning (P < 0.001). The higher level of contamination occurred on the interior surface of carcasses along the vertebral area. Therefore, the dissemination of CNST on carcasses seemed to be affected by the stunning method, carcass splitting, and carcass washing. The carcass weight significantly affected the level of CNST contamination on the carcass (P < 0.01) but there was no interaction with the stunning method.     

An exploratory observational study to develop an improved method for quantifying beef carcass salable meat yield

Eighty-seven grain-finished steers were harvested, evaluated, and fabricated into wholesale cuts to determine what measured composition indicators most accurately describe the percentage of closely trimmed salable meat yield. Indicators of lean and fat composition present at the cross-section between the 12th and 13th ribs were objectively evaluated using Assess image analysis software. Salable meat yield ranged from 50.18% to 72.92%, trimmable fat yield ranged from 12.87% to 36.69%, and bone yield ranged from 10.07% to 19.21%. Regression models were developed to estimate percentage of total salable meat yield. Composition indicators chosen to predict salable meat yield included hot carcass weight (HCW), perinephric fat weight, longissimus muscle area (LMA), subcutaneous fat thickness (SFT), ratio of LMA to subcutaneous fat area, and ratio of subcutaneous fat depth to HCW. These results indicate that prediction of beef carcass salable meat yield can be improved via modification to current measures used in the USDA yield grade equation and addition of new measures.     

Effect of source of dietary fat on pig performance,carcass characteristics and carcass fat content,distribution and fatty acid composition

Seventy gilts were used to compare the effect of including 10% tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), a fat blend (FB), or an oil blend (OB) in finishing diets vs. feeding a semi-synthetic diet with no added fat (NF) on pig performance, carcass traits and carcass fatty acid (FA) composition. Carcasses from SFO-fed gilts had greater fat and lower lean compositions than carcasses from T-fed gilts. Gilts fed NF had greater loin fat than FB-fed gilts, and greater flare fat, loin intermuscular fat and fat:lean than T-fed gilts. Bellies from NF-fed gilts had lower lean and higher intermuscular fat and fat:lean than other diets except HOSF. Fat source had minor effects on animal performance, carcass characteristics and carcass fat content and distribution, whereas feeding NF resulted in carcasses and major cuts with higher fat content. Diets rich in polyunsaturated FA (PUFA) did not reduce fat deposition in separable fat depots with respect to monounsaturated FA (MUFA) and saturated FA (SFA). Carcasses from gilts fed NF had a high degree of saturation (40.6% SFA) followed by carcasses of T- and FB-fed gilts. Feeding HOSF, SFO and LO enriched diets elevated the percentages of MUFA (56.7%), n−6 (30.0%) and n−3 (16.6%) PUFA, respectively, whereas carcasses from gilts fed OB had greater percentages of n−3 FA (14.8% n−3, 0.9% EPA, 1.0% DPA, 3.1% DHA) than gilts fed FB (6.72% n−3, 0.1% EPA, 0.4% DPA, 0.1% DHA).     

The use of ultrasound to predict the carcass composition of live Akkaraman lambs

The aim of this study was to measure fat thickness, area and depth of the longissimus dorsi muscle using ultrasonography, to estimate carcass composition in live Akkaraman lambs. Fat thickness, area and depth of the longissimus dorsi muscle between the 12th and 13th ribs were measured in vivo and on the carcass after slaughter, using real time ultrasound in 40 Akkaraman lambs. To estimate the carcass composition, one-half of a carcass was dissected into muscle, fat and bone after slaughter. Overall, correlation coefficients between ultrasound and carcass longissimus dorsi muscle area, depth and fat thickness were 0.82, 0.60 and 0.77, respectively. Estimates of carcass composition for Akkaraman lambs based on LW explained 78%, 82%, 74%, 52%, 75%, 36% and 72% of the variations for muscle, total carcass fat, subcutaneous fat, inter-muscular fat, non-carcass fat, tail fat and bone, respectively. The introduction of UFT, ULMA and ULMD as independent variables in addition to LW in the multiple linear regression equations further improved the variations for total muscle (80%), carcass fat (84%) and bone weight (76%) whereas no improvement was observed for subcutaneous, intermuscular, non-carcass and tail fat. The results showed that in vivo ultrasound fat thickness and measurement of area and depth of the longissimus dorsi muscle in association with live weight could be used to estimate muscle, total body fat and bone weight in Akkaraman lambs.     

Survival of Pseudomonas fluorescens on beef carcass surfaces in a commercial abattoir

The influence of a commercial chilling process (18 h at 10 °C followed by up to 78 h at 2 °C) on Pseudomonas fluorescens inoculated on beef carcass surfaces at four sites, neck (NE), outside round (OR), brisket (BR) and foreshank/brisket (FB) before chilling (“hot inoculated”) or after chilling for 24 h (“cold inoculated”) was investigated. Pseudomonas counts increased significantly at all sites on “hot inoculated” carcasses during storage, but on “cold inoculated” carcasses, counts declined or remained unchanged. On hot and cold inoculated carcasses, differences in Pseudomonas growth or survival were demonstrated between sites. No clear relationships were observed between Pseudomonas growth or survival and chiller relative humidity (RH) or surface water activity (a_w) at the different sites. These results were unexpected, and are discussed in relation to environmental factors that affect the growth/survival of P. fluorescens on carcass surfaces during chilling i.e. temperature, RH, and the relationship of these parameters to surface water activity (a_w).     

Fatty acid composition and interrelationships among eight retail cuts of grass-feed beef

The aim of this research was to evaluate: 1) fatty acid (FA) profile of eight retail cuts (eye of round, ribeye, top round, striploin, tenderloin, top-sirloin, underblade, ground beef) from grass-fed steers, 2) the association between striploin (longissimus muscle) FA profile and that from the other retail cuts, and 3) the changes in FA profile associated with retail cut total FA content. All of the retail cuts, except underblade and ground beef, would be considered lean (< 10 g) based on total FA content. Total saturated fatty acids were positively correlated to total FA content; whereas, negative correlations were observed with total FA content and total monounsaturated and polyunsaturated fatty acids. No correlation was observed between total FA and CLA cis-9, trans-11. Striploin trans-11 C18:1 and CLA cis-9, trans-11 proportions, and n-6:n-3 ratio were positive and highly correlated with those in the other retail cuts.     

Lipid composition of the intramuscular fat of beef from Spanish cattle breeds stored under modified atmosphere

The lipid composition of intramuscular fat from 30 young bulls of 5 Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica and Retinta) was studied. Steaks from each shortloin were packaged in 60% O(2), 30% CO(2) and 10% N(2) and aged for 0, 5, 10 and 15 days. Lipid classes obtained by thin layer chromatography and total fatty acids obtained by gas chromatography were evaluated. Meat from Asturiana de los Valles had high PL and C contents, and low TG contents that reflected its low intramuscular percentage content. This breed showed high FFA content that likely originated from lipolysis of PL. The main breed effect was due to the low intramuscular fat content observed in the Asturiana de los Valles. After 5 days, FFA decreased because they were probably transformed into other compounds. The Morucha breed may have a genetic predisposition for depositing MUFA, and the high MUFA and C14:0 values observed in the Morucha breed were likely due to its high intramuscular fat percentage. Regarding fatty acid composition, no "days of storage" effect was observed for any of the studied fatty acids, except for C18:3ω6 that increased during the first 5 days of storage in Asturiana de los Valles. Concerning the fatty acid composition, Asturiana de los Valles had the highest PUFA/SFA ratio, while Parda Alpina and Morucha possessed low ω6/ω3 ratios but high C22:6ω3 contents. Finally, the presence of C22:6ω3 and 15-CH(3)-C16:0 may be related to higher intramuscular fat contents.     

Prediction of lamb carcass composition and meat quality using combinations of post-mortem measurements

Various post-mortem measurements (carcass weights, conformation and fatness classes, external carcass dimensions, eye muscle dimensions, subcutaneous fat depth, pH and temperature) were recorded on 197 Texel (TEX) and 200 Scottish Blackface (SBF) lamb carcasses. The potential use of these measurements to predict carcass composition and key meat quality traits was investigated, to enable categorisation of carcasses in the abattoir and/or for use in genetic improvement programmes. By combining different measurements, accurate predictions of dissected carcass muscle weight (adjusted R² 0.93 in TEX, 0.88 in SBF) and fat weight (adjusted R² 0.84 in TEX, 0.87 in SBF) were achieved, and moderate predictions of intra-muscular fat (adjusted R² 0.56 in TEX, 0.48 in SBF), whilst shear force was predicted with low to moderate accuracy (adjusted R² < 0.33 across breeds and cuts). Sex, eye muscle dimensions and subcutaneous fat depth improved predictions of carcass composition and intra-muscular fat, whilst pH or temperature provided little additional benefit for these traits, but increased prediction accuracies for shear force. These results could contribute to the development of automated carcass grading systems or help inform breeding decisions.