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.     

Effectiveness of morphometric measurements for improvement of the prediction accuracy of beef carcass composition

Investigations were conducted into the effectiveness of morphometric measurements (MM) of beef carcass for the prediction of weights and percentages of muscle and fat using 237 carcasses of two pure and five cross-bred breed types. In addition to the MM, side weight (CW) and cross-sectional (SM) measurements were used for prediction by multiple regression analysis, singly or in combinations of these measurements. The cross-sectional measurements were made on three sections of a rib joint named R6, R9 and R12 which were cut at the anterior position of the 6th, 9th and 12th thoracic vertebrae. For the prediction of weights and percentages of muscle and fat, the MM group was the best predictor. The CW was effective only for the improvement of tissue weight prediction. The CW + MM +  SM(R12) and the MM + SM(R12) combinations were best for the tissue weight and the percentage prediction, respectively. A synergistic effect was observed between MM and SM for the improvement of tissue percentage prediction accuracy. Regrouping the data to three breed types by morphological differences and analyzing it by a principal component analysis improved the prediction accuracy. Carcass weight range which caused differences in carcass fat content did not affect the prediction accuracy of muscle and fat percentages in the carcass when MM were used.     

Estimation of chemical carcass composition from 8th rib characteristics with Belgian blue double-muscled bulls

Characteristics from the 8th rib cut: chemical composition, tissue composition after dissection, specific gravity (SG) and m. longissimus thoracis (LT) composition, collected on 17 Belgian Blue double-muscled fattening bulls were used to generate equations for predicting chemical carcass composition. Carcass composition was best predicted from chemical analysis of the 8th rib cut and the empty body weight (EBW) of the bull. Carcass chemical fat content (CCF, kg) was predicted from the 8th rib cut fat content (ether extract, 8RF, kg) by the following regression: CCF=1.94+27.37 8RF (R(2)=0.957, RSD =9.89%). A higher coefficient was found for carcass water (CCW, kg) predicted from 8RF and EBW: CCW=-2.26+0.28 EBW-34.28 8RF (R(2)=0.997, RSD=1.48%). No parameter was found to improve the prediction of CCP from EBW solely: CCP=-0.86+0.08 EBW (R(2) =0.992, RSD=2.61%). Prediction equations based solely on LT composition had low R(2) values of between 0.38 and 0.67, whereas no significant equations were found using SG. However, equations based on EBW had R(2) values between 0.78 and 0.99. Chemical components of the 8th rib cut in combination with EBW are most useful in predicting the chemical composition of the carcass of Belgian-Blue double-muscled bulls.     

Genetic parameters for carcass composition and performance data in crossbred lambs measured by Video Image Analysis

A total of 7074 crossbred lambs, produced by mating crossbred Mule ewes with terminal sire rams were used in this study. Of these, 630 were scanned using a Video Image Analysis (VIA) to estimate carcass quality traits. Genetic parameters for average daily gain (ADG), scanning live weight (SW), ultrasonic measures of muscle (UMD) and fat (UFD) depths, cold carcass weight (CCW) and VIA measurements of primal carcass joint weights (LEG, CHUMP, LOIN, BREAST and SHOULDER) were estimated using multivariate animal models. Additionally, VIA traits were evaluated under a repeatability model, considering the primal joints as repeated measures of the same trait. Direct heritability estimates were low to moderate (0.08–0.26) for VIA measurements of primal joints. Repeatability estimates for VIA traits were high (>0.90). Moderate to high heritability estimates (0.25–0.55) were found for performance traits (ADG, SW, UMD and UFD) and CCW. Genetic correlations between VIA traits and ADG were strong (0.75–0.93). Most of the VIA traits were highly correlated to SW (0.60–0.97). UFD was significantly negatively correlated with UMD (−0.22), ADG (−0.18) and CCW (−0.18). The results of this study suggest that selection on performance and carcass traits, measured by VIA, could possibly improve primal meat yield of carcass cuts without increasing the overall carcass fatness. High repeatability estimates of VIA traits and moderate heritabilities of the most valuable carcass joints suggests that including VIA information in breeding programs would be useful in order to improve carcass quality.     

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.     

Productivity and carcass characteristics of pure and crossbred Chinese Yellow Cattle

The carcass characteristics of 334 Chinese Yellow Cattle, and their Simmental and Limousin crosses, were investigated in abattoirs in Hebei and Sandong provinces of China. The overall slaughter age was 4.8±2.2 years at a mean liveweight of 527.28±77.0 kg. Mean ages and liveweights for Yellow Cattle and its crosses were, respectively, 5.29±2.03 and 2.85±1.71 years and 519.43±78.7 and 563.13±56.8 kg. Carcass weights varied considerably and, consequently, so did subcutaneous fat depths and dressing percentages. Overall, mean carcass weights, subcutaneous fat depths and, dressing percentages and eyemuscle areas were 283.9±64.1 kg, 14.0±8.0 mm, 54.0±4.0%, and 62.7 ±13.3 cm², respectively. Compared with pure Yellow Cattle, the crosses were slaughtered at younger age, and had larger live and carcass weights, higher dressing percentages, less subcutaneous fat depth and bigger eyemuscle areas. It is concluded that crossbreeding can significantly improve Yellow Cattle' meat productivity, however feeding systems need to be improved and an appropriate grading system developed to improve beef production and quality in China.     

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.     

Sheep carcass composition estimated from Longissimus thoracis et lumborum muscle volume measured by in vivo real-time ultrasonography

The use of Longissimus thoracis et lumborum muscle (LM) volume measured in vivo by real-time ultrasonography (RTU) to estimate carcass composition was evaluated in 47 female sheep. Animals were scanned over six sites (7th, 9th, 11th and 13th thoracic vertebrae and 2nd and 4th lumbar vertebrae). After slaughter carcass weight (CW) and composition by dissection were determined. RTU volume measurements were calculated by multiplying the LM area at each site by the vertebra lengths. Equivalent measurements to those taken in vivo were obtained on the carcass using a digital camera and image analysis. The correlation between LM volume measured by RTU and in the carcass was high for all scans. LM volume was better in predicting carcass muscle than carcass fat. Lower determination coefficients were obtained between LM volume and carcass tissues expressed in % of CW. The best estimates of carcass tissues weights and proportions were obtained using the LM volume between the 2nd and the 4th lumbar vertebrae for all tissues.

Multiple regression equations were fitted using live weight (LW) and LM volume to predict carcass composition. For all tissues, the best fit was obtained with two, three or four independent variables and the stepwise procedure was consistent in selecting LW to establish the prediction equations. Weights and proportions of muscle, subcutaneous fat, intermuscular fat and total fat were accurately predicted.

These results indicate that Longissimus thoracis et lumborum muscle volume measured in vivo by RTU can be used to predict sheep carcass composition (muscle and fat).     

Evaluation of Video Image Analysis (VIA) technology to predict meat yield of sheep carcasses on-line under UK abattoir conditions

The Meat and Livestock Commission’s (MLC) EUROP classification based scheme and Video Image Analysis (VIA) system were compared in their ability to predict weights of primal carcass joints. A total of 443 commercial lamb carcasses under 12 months of age and mixed gender were selected by their cold carcass weight (CCW), conformation and fat scores. Lamb carcasses were classified for conformation and fatness, scanned by the VIA system and dissected into primal joints of leg, chump, loin, breast and shoulder. After adjustment for CCW, the estimation of primal joints using MLC EUROP scores showed high coefficients of determination (R²) in the range of 0.82–0.99. The use of VIA always resulted in equal or higher R². The precision measured as root mean square error (RMSE) was 27% (leg), 13% (chump), 1% (loin), 11% (breast), 5% (shoulders) and 13% (total primals) higher using VIA than MLC carcass information. Adjustment for slaughter day and gender effects indicated that estimations of primal joints using MLC EUROP scores were more sensitive to these factors than using VIA. This was consistent with an increase in stability of the prediction model of 28%, 11%, 2%, 12%, 6% and 14% for leg, chump, loin, breast and shoulder and total primals, respectively, using VIA compared to MLC EUROP scores. Consequently, VIA was capable of improving the prediction of primal meat yields compared to the current MLC EUROP carcass classification scheme used in the UK abattoirs.     

Relationships of fat-tail dimensions with fat-tail weight and carcass characteristics at different slaughter weights of Torki-Ghashghaii sheep

The purpose of this research was to investigate the relationship between fat-tail and carcass attributes in Torki-Ghashghaii sheep. Thirty ram lambs belonging to six weight groups (weighing from 25 to 50kg) were used. Fat-tail measurements were recorded on the live animals before slaughter. Hot and cold (after 24h in the cold room) carcass weights, and the weights of the tail and internal organs were recorded. The carcass was dissected into conventional cuts. Each cut was de-boned and the physically separable fat was removed from the meat. The bone, physical fat and trimmed meat were weighed separately. The weight of trimmed meat as a percentage of slaughter weight did not change significantly from 25 to 50kg live weights (23.4-25.3%). The weights of physically separated fat and the fat-tail as a percentage of live weight varied from 6.6% to 15.5% for various weight groups. The correlation coefficients between the tail weight and dimensions were large, positive, and significant. The highest correlation coefficient was found between the tail weight and upper circumference (r=0.88), and the lowest one was found between the tail weight and upper thickness (r=0.61). The upper and lower circumferences of the tail accounted for 85% of the total variation in the tail weight. The tail weight was positively correlated with the meat chemically determined fat (ether extract; r=0.43; P<0.05) and with the total body fat (r=0.70; P<0.01). Further studies are needed to see whether inclusion of fat-tail measurements in breeding programs would result in a decrease in body fat in this breed.     

Investigations into the accuracy of prediction of beef carcass composition using subcutaneous fat thickness and carcass weight II. Improving the accuracy of prediction

Attempts were made to improve the accuracy of prediction of carcass components in 68 steer carcasses using a subcutaneous fat thickness measurement (FTP(8)) and hot side weight as the principal or sole predictors. When carcasses were divided into two weight ranges, prediction of the percentages of carcass fat (fat %) and muscle (muscle %) in the lighter group, using FTP(8), were almost as accurate (fat %: RSD, 1.83; R(2), 0.73; muscle %: RSD, 1.70; R(2), 0.47) as those given by multiple regression measurements made by advanced technologies. Prediction in the heavier weight group was unsatisfactory, featuring high RSDs and a low R(2). Because breed differences in prediction did not occur in the lighter group, a single prediction equation could be used for each carcass component. The use of fat thickness groups gave a similar result to that of weight groups. Once weight groups were used, curvilinear analysis did not improve the accuracy of prediction. In the lighter carcasses, the addition of hot side weight, eye muscle area and muscle score, singly or in combination, did not improve the accuracy of percentage predictions. In the heavier carcasses, the addition of hot side weight and eye muscle area was necessary to give prediction of a modest level of accuracy. For the prediction of the weights of carcass components, the addition of hot side weight to FTP(8) gave the most accurate prediction in light carcasses (fat weight: RSD, 1.60; R(2), 0.92; muscle weight: RSD, 2.08; R(2), 0.97). In the heavy carcasses, hot side weight and eye muscle area added to FTP(8) gave the most accurate prediction (fat weight: RSD, 4.40; R(2), 0.69; muscle weight: RSD, 3.73; R(2), 0.88). Because of the high level of variance explained, it is recommended that weights of carcass components be predicted, particularly in heavy carcasses.     

Variation in the carcass characteristics of commercial British cattle

Classification records for 1,150,000 beef carcasses, a one-third sampleof those classified by the Meat and Livestock Commission between 1973 and 1976, were used to examine the variation in weight, fatness and conformation of commercial British cattle. The overall ratio of male cattle (steers and young bulls) to heifers was 2·35 and young bulls comprised 4% of male cattle. There were only minor changes in the carcass characteristics over the three-year period considered. Mean carcass weights for steers (S), heifers (H) and young bulls (YB) were 264, 219 and 236 kg, respectively. Carcass subcutaneous fat percentages (SF(e)) were estimated from the distribution of carcasses between fat classifications. SF(e) for the three sexes were 8·21 (S), 8·81 (H) and 6·24 (YB). Regressions of SF(e) on carcass weight (kg) were 0·031 (S), 0·041 (H) and 0·026 (YB). There were important differences in the characteristics of carcasses from abbattoirs in different regions of the country. Carcass weights for steers ranged from 248 kg (northern England) to 280 kg (northern Scotland). Cattle slaughtered in northern Scotland were also fattest: SF(e) were 9·51 (S) and 10·2 (H). Using classification records, together with results from MLC dissection studies, national waste fat production in 1976 was estimated to be 48,000 t.     

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.     

猪胴体瘦肉率仪器测定值与生猪品种等级的关系研究

使用PG100瘦肉率测定仪,对四种不同品种等级的生猪屠宰后的胴体的瘦肉率进行了测定,并与精确分割试验测定的瘦肉率进行了比较。结果表明使用仪器测定的瘦肉率指标,能够较好地反映生猪品种等级的优劣,可以用于生猪屠宰过程中的智能分级。     

Dietary energy and protein effects on partitioning of carcass components in beef cattle

This study evaluated carcass and wholesale cut composition of 20 Angus steers fed two levels of protein (LP = 8% versus HP = 14%) at two levels of energy intake (LE = 1·96 versus HE = 2·67 Mcal ME) at 6·35 kg head⁻¹ d⁻¹ dry matter intake for 238 d using a factorial arrangement (n = 5/diet). The left side of each carcass was physically separated into wholesale cuts and each cut was, in turn, physically separated into the lean, subcutaneous fat, intermuscular fat, bone portions and cavity fat when applicable. Intramuscular fat for the entire side was chemically determined using only the separated lean tissue component. Energy was the greatest source of variation (P < 0·05) on carcass and wholesale cut composition: HE was associated with more total carcass fat (32·4 versus 23·9%) and less lean (56·7 versus 60·2%) and bone (17·9 versus 20·1%) than LE. Protein by energy level interactions (P < 0·05) were observed for carcass subcutaneous fat and carcass lean in addition to brisket subcutaneous fat, round subcutaneous fat and bone. The HP:HE group had the least carcass lean and the most subcutaneous fat followed by the LP:HE group, LP:LE and then HP:LE. This was also the trend for the wholesale cut composition. These results suggest that fat deposition in cattle can be significantly and favorably reduced in wholesale cuts by adjusting the relative balance of dietary protein and energy.     

Effects of weight at slaughter and sex on the carcass characteristics of Florida suckling kids

The effect of slaughter weight and sex on some carcass traits of suckling kids of the Florida breed was evaluated. A total of 60 kids (30 male and 30 female), fed exclusively on milk replacers, were slaughtered at 7-8kg (group 1), 10-11kg (group 2) or 14-15kg (group 3) of liveweight (mean weights of 7.6kg, 10.8kg and 14.4kg, respectively). Higher slaughter weights decreased the percentage of subproducts (blood, skin, head, feet) and internal organs (lungs+traquea, heart, liver, spleen, thymus) but significantly increased the percentage of intestine and fat depots (omental fat and mesenteric fat). Higher slaughter weights also increased carcass measures (L 40.5 vs 49.1; F 22.5 vs 25.9; G 10.4 vs 14.2; Wr 10.1 vs 13.9; Wth 8.0 vs 10.5; Th 16.5 vs 199; B 32.3 vs 42.4; PT 41.5 vs 50.8), compactness carcass index (96.6 vs 152.3) and compactness leg index (27.5 vs 44.1). Sex only significantly affected the percentages of feet, internal organs, omental fat, measure L, carcass compactness index and hind limb compactness index. The meat colour and fat colour were mainly scored as pale and white respectively in the carcasses of the lightest animals, whereas heavier kids were scored as pink and cream. Slaughter weight also influenced significantly the carcass fatness (score 1 in lightest kids and 2 or 3 in heavier ones). There were no significant (p>0.05) differences between slaughter weight group and sex in dressing percentages. Percentages corresponding to the long leg, back and neck (30-33%, 18-19% and 8-10%, respectively) decreased when the slaughter weight increased, whereas the ribs (23-25%) and the flank (10-11%) increased slightly. The carcasses comprised 57-58% muscle, 22-25% bone, 5-6% subcutaneous fat and 9-12% intermuscular fat. The percentage muscle stayed the same with increasing slaughter weight, whereas the bone decreased and the fat increased. The carcasses of the heavier females contained less lean and more fat than the males. The bone percentage was significantly (p<0.05) lower in the females and the carcass fat percentage was significantly (p<0.05) higher than in the males.     

The relationship of carcass measurements to carcass composition and intramuscular fat in Spanish beef

Forty beef carcasses were classified for conformation and fatness. Besides, carcass weight, fat thickness (FT), carcass dimension, marbling by computer image analysis and ultrasound readings was recorded to complement grading. For predicting intramuscular fat (IMF) content, FT, number of intramuscular flecks and conformation increased R²-value from 0.19 to 0.64 compared to conformation alone. For visual marbling, ultrasound readings and thoracic depth (TD) increased the R²-value from 0.24 to 0.57 compared to fatness score (FS). The best variables for predicting weight of fabricated subprimals were carcass weight or compactness which is a function of carcass weight (R² between 0.94 and 0.63). Fatness score was poorer than FT for predicting yield of subprimals cuts from round (R² = 0.16 vs. 0.50) and ultrasound readings for less valuable subprimals (R² = 0.31 vs. 0.39). These results showed that other variables could be used in combination with carcass fatness or conformation to achieve a more accurate estimation of fat and carcass yield.     

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.     

Carcass and meat quality of Assaf milk fed lambs: Effect of rearing system and sex

The effect of sex and rearing system on growth and carcass and meat characteristics of milk fed Assaf lambs was studied. Thirty-six lambs, 18 males and 18 females were used. Twelve lambs remained with their mothers throughout the experiment (NR). Within 24–36 h of birth, the rest were housed individually and fed twice a day ad libitum (AAR) or at 70% of ad libitum consumption (RAR) with reconstituted cow’s milk. Sex did not affect animal performance, yet females showed higher carcass and non-carcass fat deposits. NR lambs showed greater BWG than AAR fed lambs, and AAR, higher than the RAR. Differences between naturally and artificially reared lambs in CCW and killing out percentage were not significant. Empty digestive tract and mesenteric fat weights were greater for RAR than NR lambs, with the AAR lambs demonstrating intermediate values; conversely, omental fat was greater in NR lambs. Carcass ether extract content was greater for NR lambs, possibly due to the greater growth. Use of ad libitum cow’s milk substitute in suckling lambs twice a day resulted in less body weight gain but similar killing out percentages compared to naturally raised lambs. A 70% restricted supply increased the days in suckling and reduced carcass fatness and compactness. Except for water loss, which was less in NR than artificially fed lambs, no differences were found in meat characteristics.     

Prediction of lamb meat eating quality in two divergent breeds using various live animal and carcass measurements

This study investigated how accurately taste panel sensory assessments of meat eating quality (MEQ) could be predicted in two divergent lamb breeds, using predictors measured in live animals (weights, subjective conformation assessments, ultrasound, computed tomography (CT) and video image analysis measurements) and carcasses (weights, MLC fat and conformation classes, pH, temperature, carcass dimensions and cross-sectional tissue dimensions), individually and in optimal combinations. Grilled muscle samples from the pelvic limb (semimembranosus) and loin (Longissimus lumborum) of 120 Texel (TEX) and 112 Scottish Blackface (SBF) lambs were assessed by a trained taste panel for texture, juiciness, flavour, abnormal flavour and overall liking. Residual correlations (adjusted for fixed effects, age and sire) between MEQ and predictor traits were low to moderate in size (<±0.42). MEQ traits predicted best by single measurements were loin flavour and overall liking for TEX (using fat area in a CT scan or subcutaneous fat depth measured post-mortem), and for SBF were leg texture (using carcass weight or temperature) and juiciness (using CT fat area or shoulder conformation score). Combining live animal and carcass measurements increased MEQ prediction accuracies, compared with using either set alone, to explain >40% of residual variation in several MEQ traits, with the highest adjusted R² values for leg juiciness in TEX (0.53) and leg texture in SBF (0.59). The most useful predictors of MEQ depended on breed, with measurements of fatness generally more important in the lean breed and carcass size and muscling more important in the fatter breed.