The value of carcass weight, fat depth measures and eye muscle area for predicting the percentage yield of saleable meat in Australian grass-fed beef carcasses for Japan

The percentage saleable meat yield was determined for 42 carcasses from grass-fed steers representing a range of breed types purchased in Australia for the Japanese market. Their mean (s.d.) carcass weight and P8 fat depth were 329 (28.1) kg and 17.3 (4.3) mm, respectively. All measures of subcutaneous fat depth were significantly (P < 0.05) and moderately correlated with percentage saleable meat yield, with measures in the loin region showing a stronger association than those taken in the rump region. The association between P8 fat depth and the loin measures of subcutaneous fat were low and there was a significant (P < 0.05) association only between P8 and fat depth at the 10th rib (FD 10). The use of fat depth measurements from the loin region reduced the error associated with predicting saleable meat yield more than those from the rump region and significantly increased the amount of variation (R(2)) in saleable meat yield that was explained. Hot carcass weight (HCW) did not significantly (P > 0.05) improve prediction models when combined with subcutaneous fat depth measurements and overall, the R(2) values were low ranging from 0.19 to 0.42. The models indicated that fat depth measures and carcass weight are poor predictors of percentage meat yield in heavy-weight carcasses from mixed breed cattle as produced and processed in Australia. The prediction of percentage yield was in general significantly (P < 0.05) improved when measures of M. longissimus thoracis et lumborum (LD) area were added as independent variables to models based on hot carcass weight and subcutaneous fat depth measurements. With LD area added the amount of variation in yield that could be explained by the models increased by as much as 28%. Overall, the best model was based on fat depth at the 12th rib and LD area measured at the 5th rib for which the R(2) was 0.58 and the residual standard deviation was 1.63%. The next most accurate prediction of yield was provided by a model which included the independent variables used in the Australian Chiller Assessment Scheme namely HCW, FD10 and LD area at the 10th rib upon which breed type had no significant (P > 0.05) effect.     

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.     

Predicting the weight of lean meat in lamb carcasses and the suitability of this characteristic as a basis for valuing carcasses

The carcasses of 138 lambs were dissected into fat, muscle and bone as the basis for developing a model to estimate the weight of lean meat (muscle and intramuscular fat). The lambs represented two sexes (70 wethers, 68 ewes) and three sire genotypes (67 Poll Dorset, 39 Suffolk, 32 Wiltshire Horn) all from Border Leicester × Polwarth × Booroola type ewes. Hot carcass weight (HWT) was found to explain the majority of the variation in the weight of lean meat. When measures of subcutaneous fat depth at different sites were used as predictors in addition to HWT, the accuracy with which lean meat yield could be estimated was found to increase by a small amount. There was, however, little difference in their individual value as predictors. The area of the M. longissimus thoracis et lumborum at the twelfth-thirteenth rib was found to account for the significant breed type difference between Poll Dorset and Suffolk sired lambs when included in a multiple regression with HWT and the GR measurement (tissue thickness at the twelfth rib 110 mm from the midline). The final model produced an R(2) = 0·92 and an RSD = 0·45 kg for the 106 lambs. Using the model for the 106 lambs, the estimated (from the model) and actual values of lean meat for the Wiltshire Horn sired lambs were compared. The correlation coefficient between the values was r = 0·97 and the RSD was 0·31 kg. This shows that for second cross lambs as used in this study the fitted model exhibits a degree of general validity and stability. An overall model for the 138 lambs produced an R(2) = 0·92 an RSD = 0·43 kg. The potential for pricing meat on the basis of lean meat yield is discussed, with particular emphasis on the current developments in assessment of lamb carcasses in Australia.     

The assessment of carcass composition of Awassi male lambs by real-time ultrasound at two different live weights

The accuracy of ultrasonography to measure fat thickness (FT) and longissimus dorsi muscle (LM) traits (area, depth and width) in live Awassi male lambs and predict carcass FT and LM traits was studied.Twenty six Awassi male lambs were randomly divided into light (L) (n = 13) and heavy (H) (n = 13) finishing lambs. Slaughter weight of lambs in L and H groups were 40 and 45 kg, respectively. FT and LM traits, cross-sectional area between the 12th and 13th rib were measured using real-time ultrasound in vivo and on the carcass after slaughter. All ultrasound and carcass measurements were the same except live weight (LW) (P < 0.001), cold carcass weight (CCW) (P < 0.001) and carcass LM width (P < 0.05). Overall, correlation coefficients between ultrasound and carcass FT, LM depth, width and area were 0.79, 0.82 (P < 0.001); 0.60, 0.58 (P < 0.05); 0.48, −0.17 (P > 0.05) and 0.89, 0.87 (P < 0.001), respectively, for lambs in L and H groups. The introduction of ultrasound FT and ultrasound LM area as independent variables in addition to LW in the multiple regression equations further improved the variations for carcass FT (84%, 71%), carcass LM area (79%, 79%), CCW (72%, 65%) for lambs in light and heavy groups whereas no improvement was observed for carcass yield.These results indicate that in vivo ultrasound FT and measurement of the LM area in association with LW could be used to estimate carcass FT, carcass LM area and CCW in different LW Awassi lambs.     

Use of linear measurements of m. longissimus to predict the muscle content of beef carcasses

Five linear measurements associated with the eye muscle (m. longissimus), together with hot carcass weight, 10th rib fat thickness, eye muscle area and an estimate of eye muscle volume (eye muscle area × a carcass length measurement) were made on 53 chilled beef carcasses (hot weight 143-384 kg). The right side of each carcass was anatomically dissected into muscle, bone, fat and connective tissue. Correlation and regression analyses were used to identify the most accurate predictors of weight and percentage of side muscle. In simple regression, hot carcass weight and the estimate of eye muscle volume were the most accurate predictors of side muscle weight; 10th rib fat thickness and MN, a depth measurement of muscle and fat over the loin, were the most accurate predictors of percentage side muscle. In multiple regression, the addition of either eye muscle volume or eye muscle area to hot carcass weight and 10th rib fat thickness gave the most accurate predictions of side muscle weight and percentage side muscle, but in the case of each dependent variable, the improvement in accuracy was slight compared with that of the two most accurate regressors, hot carcass weight and 10th rib fat thickness. Although eye muscle volume was a more accurate predictor of side muscle weight than eye muscle area in simple regression, their contributions in multiple regression with hot carcass weight and 10th rib fat thickness were similar. None of the five linear measurements associated with m. longissimus contributed significantly to improving the prediction of weight or percentage of side muscle.     

Halothane genotype and pork quality. 1. Carcass and meat quality characteristics of three halothane genotypes

The carcass and meat quality characteristics of three halothane genotypes in pigs were evaluated. Sixty crossbred Landrace×Large White pigs (NN=25, Nn=19, nn=16) of ±86 kg live weight were slaughtered, the carcasses chilled for 24 h at 2°C, certain carcass and meat quality traits determined and the shoulder and leg cuts deboned and cut into primal cuts. Dressing percentage of the Nn pigs was higher (P<0.05) than that of the NN and nn pigs. Carcass length was the longest (P<0.05) for the nn pigs. Midline fat measurements as well as measurements at the 2nd-3rd last rib (45 mm from the midline) indicated that the nn pigs had less fat (P<0.05) and a larger eye muscle width (P<0.05), depth (P<0.001) and area (P<0.001) than the NN or Nn pigs. This resulted in the nn pigs having the highest (P<0.05) percentage predicted carcass lean content. Fat, bone and lean yield of the shoulder identified the nn pigs with the least bone (P<0.05) and fat (P<0.001) and the highest lean yield (P<0.05), expressed as a percentage of total shoulder weight. Yield from the legs identified the nn pigs as having the lowest fat (P<0.001) and highest lean (P<0.05), expressed as a percentage of total leg weight. The primal lean cuts (topside, silverside, thickflank and rump) from the legs showed that the nn pigs had the highest values (P<0.05) for lean as a fraction of cold carcass weight. This resulted from the higher weight of these cuts (P<0.05) in the nn pigs. Calculation of bone yield in the legs showed that the femur weights were highest (P<0.05) for the Nn pigs, also when expressed as percentage of leg weight (P<0.05) and as a fraction of cold carcass weight (P<0.05). Comparison of meat quality traits show that the nn pigs had poor quality with regard to pH(45) (P<0.001), pH(24) (P<0.05), drip loss (P<0.001) and reflectance values (P<0.05).     

Video image analysis in the Australian meat industry - precision and accuracy of predicting lean meat yield in lamb carcasses

A wide selection of lamb types of mixed sex (ewes and wethers) were slaughtered at a commercial abattoir and during this process images of 360 carcasses were obtained online using the VIAScan? system developed by Meat and Livestock Australia. Soft tissue depth at the GR site (thickness of tissue over the 12th rib 110 mm from the midline) was measured by an abattoir employee using the AUS-MEAT sheep probe (PGR). Another measure of this thickness was taken in the chiller using a GR knife (NGR). Each carcass was subsequently broken down to a range of trimmed boneless retail cuts and the lean meat yield determined. The current industry model for predicting meat yield uses hot carcass weight (HCW) and tissue depth at the GR site. A low level of accuracy and precision was found when HCW and PGR were used to predict lean meat yield (R(2)=0.19, r.s.d.=2.80%), which could be improved markedly when PGR was replaced by NGR (R(2)=0.41, r.s.d.=2.39%). If the GR measures were replaced by 8 VIAScan? measures then greater prediction accuracy could be achieved (R(2)=0.52, r.s.d.=2.17%). A similar result was achieved when the model was based on principal components (PCs) computed from the 8 VIAScan? measures (R(2)=0.52, r.s.d.=2.17%). The use of PCs also improved the stability of the model compared to a regression model based on HCW and NGR. The transportability of the models was tested by randomly dividing the data set and comparing coefficients and the level of accuracy and precision. Those models based on PCs were superior to those based on regression. It is demonstrated that with the appropriate modeling the VIAScan? system offers a workable method for predicting lean meat yield automatically.     

The use of seemingly unrelated regression to predict the carcass composition of lambs

The aim of this study was to develop and evaluate models for predicting the carcass composition of lambs. Forty male lambs were slaughtered and their carcasses were cooled for 24 hours. The subcutaneous fat thickness was measured between the 12th and 13th rib and breast bone tissue thickness was taken in the middle of the second sternebrae. Left side of carcasses was dissected and the proportions of lean meat (LMP), subcutaneous fat (SFP), intermuscular fat (IFP), kidney and knob channel fat (KCFP), and bone plus remainder (BP) were obtained. Models were fitted using the seemingly unrelated regression (SUR) estimator which is novel in this area, and compared to ordinary least squares (OLS) estimates. Models were validated using the PRESS statistic. Our results showed that SUR estimator performed better in predicting LMP and IFP than the OLS estimator. Although objective carcass classification systems could be improved by using the SUR estimator, it has never been used before for predicting carcass composition.     

The use of seemingly unrelated regression to predict the carcass composition of lambs

The aim of this study was to develop and evaluate models for predicting the carcass composition of lambs. Forty male lambs were slaughtered and their carcasses were cooled for 24 hours. The subcutaneous fat thickness was measured between the 12th and 13th rib and breast bone tissue thickness was taken in the middle of the second sternebrae. Left side of carcasses was dissected and the proportions of lean meat (LMP), subcutaneous fat (SFP), intermuscular fat (IFP), kidney and knob channel fat (KCFP), and bone plus remainder (BP) were obtained. Models were fitted using the seemingly unrelated regression (SUR) estimator which is novel in this area, and compared to ordinary least squares (OLS) estimates. Models were validated using the PRESS statistic. Our results showed that SUR estimator performed better in predicting LMP and IFP than the OLS estimator. Although objective carcass classification systems could be improved by using the SUR estimator, it has never been used before for predicting carcass composition.     

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.     

Predicting the composition of lamb carcases using alternative fat and muscle depth measures

Hot carcase weight (HCW) and the GR tissue depth (total tissue depth over the 12th rib, 110 mm from the midline) were measured on 312 crossbred (Poll Dorset × Merino) lambs with a mean live weight of 47 kg. At a position 30 mm distal to the lumbar-sacral junction, the depth (RMD) of the rump muscles was measured along with subcutaneous fat depth overlaying the m. gluteus medius (RFD). The subcutaneous fat depth over the m. longissimus (loin) at the 12th rib was measured (Fat C), as was the depth and width of the loin cross section (EMD and EMW, respectively). The right side of each carcase was scanned by a dual energy X-ray bone densitometer and fat and lean weight determined and the percentage of lean and fat content in the carcases calculated. HCW alone accounted for 26% of the variation in percentage lean content (LC), with GR measurement being the single best predictor of LC (R² = 48.1; r.s.d. = 1.89). RFD provided a less accurate and precise estimate of LC (R² = 37.3; r.s.d. = 2.07) than either GR or Fat C (R² = 46.5; r.s.d. = 1.92). Inclusion of HCW with either GR or Fat C provided a small improvement in the amount of variation in LC which could be explained. The measurement of breeding animals by ultrasound includes the terms weight, Fat C and EMD. These predictors when combined explained 49% of the variation in LC whereas by comparison measures of weight, RFD and RMD only explained 42% of the variation in LC. The current method of measuring fat depth over the 12th/13th rib is practical and measurement over the rump does not present an advantage based on the results of this study.     

Rate of carcass components gain, carcass characteristics, and muscle longissimus tenderness in lambs fed dietary protein sources with a low quality roughage diet

An experiment was conducted to examine the effects of infrequently fed (twice/week) protein supplements on rate of carcass components gain, carcass traits and tenderness of meat in lambs. Forty-three Dorset Horn×Merino wether lambs (aged 4 months) were assigned by stratified randomization (live weight basis) to five dietary treatments to compare the results with lambs fed very low quality (5.1 MJME/day) roughage diet. Lambs on control diet (BAS; treatment 1) and all other dietary treatment groups were offered ad libitum amounts of a mixed roughage diet (oat hay:lucerne hay) at the ratio of 85:15 throughout the 10-week experimental study. Supplements of barley grain with added urea and sulphate (USB, 226 g DM/day; treatment 2); lupins (LUP, 231 g DM/day; treatment 3); cottonseed meal (CSM, 152 g DM/day; treatment 4); fish meal (FM, 97 g DM/day; treatment 5) were offered at isonitrogenous amounts. Final live weight (FLW) and empty body weight (EBW) were greater (P<0.01) with FM, LUP, USB and CSM when compared with BAS. Rates of gain of carcass components observed during the experimental period resulted in lower carcass fatness (P<0.05) and greater muscle content (P<0.01) with FM; and higher (P<0.05) level of fat and muscle in the carcass with LUP compared to those on BAS diet. Other diets (USB and CSM) had less marked effects, but higher rate of daily fat gain in the carcass with LUP and CSM was indicated by greater carcass fat depth (P<0.05; the total tissue depth of muscle and fat at the twelfth rib, 110 mm from the midline; GR) and content of intramuscular fat (P<0.05), respectively. Energy gained as fat in the carcass was lowest with FM (P<0.05), highest with BAS and intermediate with all other treatments. The increase in carcass leanness and reduction in fatness with FM and USB compared to BAS and other treatments affected neither (P>0.1) meat tenderness (Warner-Bratzler shear force) nor sarcomere length of longissimus thoracis muscle. Feeding small amounts of protein supplements to lambs on very low quality forage diets during dry seasons may be a viable path to improve the carcass weight and leanness in lambs without changing the meat tenderness.     

The assessment of carcass composition of Awassi male lambs by real-time ultrasound at two different live weights

The accuracy of ultrasonography to measure fat thickness (FT) and longissimus dorsi muscle (LM) traits (area, depth and width) in live Awassi male lambs and predict carcass FT and LM traits was studied.Twenty six Awassi male lambs were randomly divided into light (L) (n = 13) and heavy (H) (n = 13) finishing lambs. Slaughter weight of lambs in L and H groups were 40 and 45 kg, respectively. FT and LM traits, cross-sectional area between the 12th and 13th rib were measured using real-time ultrasound in vivo and on the carcass after slaughter. All ultrasound and carcass measurements were the same except live weight (LW) (P < 0.001), cold carcass weight (CCW) (P < 0.001) and carcass LM width (P < 0.05). Overall, correlation coefficients between ultrasound and carcass FT, LM depth, width and area were 0.79, 0.82 (P < 0.001); 0.60, 0.58 (P < 0.05); 0.48, −0.17 (P > 0.05) and 0.89, 0.87 (P < 0.001), respectively, for lambs in L and H groups. The introduction of ultrasound FT and ultrasound LM area as independent variables in addition to LW in the multiple regression equations further improved the variations for carcass FT (84%, 71%), carcass LM area (79%, 79%), CCW (72%, 65%) for lambs in light and heavy groups whereas no improvement was observed for carcass yield.These results indicate that in vivo ultrasound FT and measurement of the LM area in association with LW could be used to estimate carcass FT, carcass LM area and CCW in different LW Awassi lambs.     

Effect of concentrate level and slaughter body weight on growth performances,carcass traits and meat quality of Barbarine lambs fed oat hay based diet

This study was conducted to evaluate concentrate level (CL) and slaughter body weight (SW) effects on growth performances, carcass traits and meat quality of Barbarine lambs. Twenty-four weaned male lambs (23.1 kg), receiving an oat-hay based diet, were allotted into two groups. The LCL group received low concentrate level (300 g) and the HCL group received high concentrate level (600 g). Lambs were slaughtered at two prefixed weights (35 and 42 kg). For each group and each weight, six lambs were slaughtered. Lambs from HCL group had higher ADG, carcass yields, carcass compactness and subcutaneous fat thickness, and lower carcass meat proportion. CL increase did not affect meat pH, meat and fat color, chemical and fatty acid composition. Late slaughtering improved carcass yields and increased carcass adiposity. However, it did not affect carcass meat proportion and shoulder tissue composition. SW had effect on meat color and fatty acid composition.     

Analysis of image-based measurements and USDA characteristics as predictors of beef lean yield

This paper describes a comprehensive analysis of the 12th rib image measurements, USDA yield characteristics and USDA yield grade as predictors of beef lean yield. The predictors were used in separate groups to construct three sets of multiple linear regression models for the prediction of lean yield of 241 carcasses. Fat thickness is traditionally considered the most useful predictor. The analysis showed that the percent rib eye area was a more useful single predictor than fat thickness, and that the average fat thickness was insignificant when rib eye area and fat area were used. While marbling is traditionally considered a predictor of quality, the results showed that marbling characteristics were also useful for yield prediction. The usually-observed large differences in accuracy between the predictions of lean weight and lean percentage were shown to result from the variations in carcass weight. Statistical diagnostics confirmed the suitability of the models developed. A neural network model was tested and the results suggested that the inclusion of nonlinearity in the predictive models did not prove beneficial. Important predictors were identified and the advantages of computer vision and image processing techniques were further demonstrated.     

Effect of suckling management on productive performance,carcass traits and meat quality of Comisana lambs

The effect of restricted suckling on productive performance, carcass traits, meat quality and skeletal development of growing lambs was studied. Twenty-one naturally suckled male Comisana lambs were divided into three equal weight groups differing in suckling management systems: (1) only maternal milk (C); (2) only maternal milk until 15th day of age, and then, till slaughter, maternal milk, concentrate and Lucerne hay ad libitum (T1); (3) only maternal milk until 15th day of age, and then from 16th to 30th days of age, maternal milk, concentrate and Lucerne hay ad libitum, and, from 31st day of age till slaughter, only concentrate and Lucerne hay ad libitum (T2). The total mean milk yield was 22.7 and 41.6 kg per ewe for T1 and T2, respectively. Restricted suckling did not significantly affect slaughter weight, hot and cold carcass weights, carcass shrink losses, pH, colour and area of Longissimus muscle, pelvic limb, or bone characteristics. Suckling management system significantly affected ADG, milk intake, dressing percentage, and percentages of intestine, stomach, offal, kidney fat, shoulder, lean and fat, and there were differences in total collagen, and hydroxylysylpyridinoline crosslink concentrations. In addition, different IMC maturity among the muscles was apparent.     

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.     

CORRELATIONS BETWEEN SERUM CONCENTRATIONS OF LEPTIN AND BEEF CARCASS COMPOSITION AND QUALITY

Steers (n = 84) of various genotypes raised under diverse management conditions from the 2001 Missouri State Beef carcass contest were used to evaluate the relationship between serum concentrations of leptin and beef carcass composition and quality. Serum and carcass data including hot carcass weight; adjusted 12^th rib fat thickness; percentage kidney; pelvic and heart fat (KPH); marbling score; and USDA yield grades were measured at harvest. Leptin was correlated with back fat thickness over the 12^th rib, yield grade, and marbling score (r = 0.35, r = 0.19, r = 0.26 , P < 0.10; respectively), but not with hot carcass weight, ribeye area, or KPH (P > 0.10). Serum concentrations of leptin may be useful to objectively evaluate carcass composition in fed cattle and may provide a means by which carcass quality can be predicted in the live animal.