In vivo estimation of sheep carcass composition using real-time ultrasound with two probes of 5 and 7.5 MHz and image analysis

Ultrasonic measurements were taken on 46 sheep using a real-time ultrasound machine equipped with 2 probes (5 and 7.5 MHz). Measurements of subcutaneous fat thickness (SC) and muscle LM depth (MD) and area (MA) were taken at 2 locations: over the 13th thoracic vertebra (SC13, MD13, and MA13, respectively) and at the interval between the third and fourth lumbar vertebrae (SC34, MD34, and MA34, respectively). Fat thickness was also measured over the third sternebra of the sternum. The relationship between carcass and in vivo ultrasound measurements was high for all the measurements (r(2) between 0.54 and 0.96, P < 0.01). Concerning MD and SC, the 7.5 MHz probe estimates were consistently more precise than the 5-MHz estimates (r(2) increased between 0.09 and 0.13), but the reverse occurred with the MA estimates, although to a lesser extent. Estimates of carcass composition for muscle, subcutaneous fat, intermuscular fat, internal fat, and total fat based on BW explained a large amount of variation in muscle (87%), subcutaneous fat (85%), intermuscular fat (79%), internal fat (74%), and total fat (87%). In most cases (55 of 70) the introduction of one ultrasound measurement in addition to BW in the multiple regression equations further improved the explanation of variation for weight of carcass tissues, internal fat, and total fat. For carcass muscle estimation, the ultrasound measurements of muscle provided an increase of r(2) between 0.05 and 0.10 (P < 0.01). The SC13 and SC34 gave the best improvements in estimating subcutaneous fat, intermuscular fat, internal fat, and total fat (r(2) increased between 0.05 and 0.17; P < 0.01). Prediction of the proportions of the carcass components (internal and total fat from BW) was clearly lower than the prediction of the absolute amounts of these traits. Inclusion of one or more ultrasound measurements in addition to BW increased the predictive ability of the equations. Both probes were useful to estimate carcass muscle depth and area and fat depth, but the 7.5-MHz probe showed a greater ability to estimate depth. For all traits, the stepwise procedure demonstrated that the best fit was obtained with BW and one or more ultrasound measurement with the 7.5-MHz probe.     

In vivo estimation of goat carcass composition and body fat partition by real-time ultrasonography

The accuracy of ultrasound measurements to assess goat carcass composition and the partition of body fat depots was evaluated. An ultrasound machine with a 5-MHz probe and image analysis was used to assess in vivo fat thickness and muscle depth in 56 Spanish Celtiberica adult goats, in lumbar and breast body regions. The goats were slaughtered and the weight of body fat depots recorded. Measurements corresponding to the in vivo ultrasound fat thickness and muscle depth were taken on carcasses. The left sides of carcasses were completely dissected into their components. The best relationships (r = 0.94, P < 0.01) between in vivo and carcass measurements of fat thickness were obtained when measurements were taken at the sternum, and the best anatomical point was located between the third and fourth sternebrae. The best correlation coefficients (r = 0.84) for muscle depth were found for measurements taken between the third and the fourth lumbar vertebrae at 2 cm from the middle of the vertebral column. Body weight and ultrasound measurements were used to fit the best multiple regression equations to predict carcass composition and the partition of body fat depots. All equations, with the exception of those for muscle quantity, omental, and total body fat depot amounts, were computed after performing a logarithmic transformation. Body weight in association with the ultrasound measurement taken at largest LM muscle depth, between the first and second lumbar vertebrae accounted for 90% of the muscle weight. Body weight was the first variable admitted into the prediction models of muscle, mesenteric fat, and total body fat and accounted for 82, 67, and 79% of the variation in tissue weights, respectively. The ultrasound measurement of fat thickness taken at the third sternebra was the first variable admitted into the prediction models for intermuscular fat, kidney and pelvic fat, and total carcass fat and accounted for by 73, 75, 71, and 79% of the variation in the weight of these fat depots, respectively. The ultrasound measurements taken in the breast region, particularly at the third and fourth sternebrae, were the most suitable for assessing fat thickness. The results of this experiment suggest that BW associated with some in vivo ultrasonic fat measurements allow the accurate prediction of goat carcass composition and body fat depots.     

Ultrasonic, needle, and carcass measurements for predicting chemical composition of lamb carcasses

Three groups (n = 147) of New Zealand mixed breed lambs averaging 170 d of age and 31.7 kg in weight were killed after a diet of pasture to determine whether the total depth of soft tissues over the 12th rib 11 cm from the dorsal midline (GR) could be measured in live lambs with sufficient accuracy to warrant its use as a selection tool for breeding flock replacements. Relationships among live and carcass measurements and carcass chemical composition also were determined. An ultrasonic measurement of GR in the live lambs was a more accurate predictor of carcass GR (r = .87) and percentage carcass fat (r = .80) than was a measurement of GR made with a needle (r = .80 and .67, respectively). Both measurements were sufficiently accurate to permit culling of over-fat lambs from breeding flock replacement prospects. The best single indicator of percentage carcass fat (r = .87) was a shoulder fat measurement, followed closely by carcass GR (r = .85). Both were superior to USDA yield grade for estimating carcass chemical composition in these young, lightweight lambs. These two measurements also were most highly related to percentage carcass protein (r = -.78 and r = -.77, respectively). These results indicate possibilities for improving the method of evaluating the composition of U. S. lamb carcasses.     

Validation of the 9-11th rib cut to estimate the chemical composition of the dressed carcass and of the whole empty body of Zebu cattle

This study was conducted to validate the 9-11th rib cut to estimate the chemical composition of the carcass and of the empty body weight (EBW) of Zebu cattle. Nineteen Zebu steers with initial body weight of 266.5±32.2 kg were used. Four steers were slaughtered at the beginning to compose the reference group; three were fed at maintenance level, and the remaining were allotted to different planes of nutrition (5.0%, 35.0% and 65.0% concentrate levels in the diets, DM basis). The 9-11th rib cuts and half of the carcasses were dissected and the weights of fat, muscle and bone tissue were recorded. The components fat, muscle and bone tissue from the 9-11th rib cut and from the half carcass were sampled and chemical analysis of fat, protein, water, ash and minerals determined. The 9-11th rib cut satisfactorily estimated the physical composition of the carcass, but not the chemical composition. The 9-11th rib cut appropriately estimated the chemical composition of the carcass in terms of protein, water, ash and macro mineral content. For the percentage of fat and Ca, an over- and underestimation of 7.84% and 13.34%, respectively, were detected. Regression equations were fitted to estimate the percentage of fat and Ca in the carcass, and that of protein, water and ash in the whole empty body.     

Using ultrasound measurements to predict body composition of yearling bulls

Carcass traits have been successfully used to determine body composition of steers. Body composition, in turn, has been used to predict energy content of ADG to compute feed requirements of individual animals fed in groups. This information is used in the Cornell value discovery system (CVDS) to predict DM required (DMR) for the observed animal performance. In this experiment, the prediction of individual DMR for the observed performance of group-fed yearling bulls was evaluated using energy content of gain, which was based on ultrasound measurements to estimate carcass traits and energy content of ADG. One hundred eighteen spring-born purebred and crossbred bulls (BW = 288 +/- 4.3 kg) were sorted visually into 3 marketing groups based on estimated days to reach USDA low Choice quality grade. The bulls were fed a common high-concentrate diet in 12 slatted-floor pens (9 to 10 head/pen). Ultrasound measurements including back-fat (uBF), rump fat, LM area (uLMA), and intramuscular fat were taken at approximately 1 yr of age. Carcass measurements including HCW, backfat over the 12th to 13th rib (BF), marbling score (MRB), and LM area (LMA) were collected for comparison with ultrasound data for predicting carcass composition. The 9th to 11th-rib section was removed and dissected into soft tissue and bone for determination of chemical composition, which was used to predict carcass fat and empty body fat (EBF). The predicted EBF averaged 23.7 +/- 4.0%. Multiple regression analysis indicated that carcass traits explained 72% of the variation in predicted EBF (EBF = 16.0583 + 5.6352 x BF + 0.01781 x HCW + 1.0486 x MRB - 0.1239 x LMA). Because carcass traits are not available on bulls intended for use as herd sires, another equation using predicted HCW (pHCW) and ultrasound measurements was developed (EBF = 39.9535 x uBF - 0.1384 x uLMA + 0.0867 x pHCW - 0.0897 x uBF x pHCW - 1.3690). This equation accounted for 62% of the variation in EBF. The use of an equation to predict EBF developed with steer composition data overpredicted the EBF predicted in these experiments (28.7 vs. 23.7%, respectively). In a validation study with 37 individually fed bulls, the use of the ultrasound-based equation in the CVDS to predict energy content of gain accounted for 60% of the variation in the observed efficiency of gain, with 1.5% bias, and identified 3 of the 4 most efficient bulls.     

Ultrasound measurements of live and carcass traits in Tswana goat kids raised under semi-intensive system in South-eastern Botswana

The aim of this study was to characterise ultrasound measurements of live and carcass traits in intact males, females and castrated Tswana goat kids from birth to 12 months of age raised under semi-intensive system in South-eastern Botswana. Measurements were recorded in 15 castrates, 15 intact males and 15 female Tswana goat kids randomly selected at birth. Ultrasonic fat and muscle depths were measured at the first, third/fourth, sixth/seventh, ninth/tenth and 12th/13th thoracic; first, third and fifth lumbar and first, second/third and fourth/fifth sternal vertebrae, fortnightly for the first 6 months and then monthly for the remaining 6 months. The animals were stunned and humanely slaughtered at 12 months of age, and ultrasound and shatterproof ruler were used to measure fat and muscle depths on the carcasses at similar sites as on live animals. A real-time B-mode ultrasound scanner fitted with LV2-1 probe operating at 7.5 MHz (Explorer V5 Vet Laptop B-Ultrasonic Scanner UMC Technology Development Co., Ltd, China) was used to predict ultrasound measurements on live animals and their carcasses. Data were analysed using general linear model in statistical analysis system. Muscle depth measurements increased significantly (p?<?0.05) with age in all sites of measurements. However, there was no significant difference between the sexes at different sites of muscle depth measurements at the same age. Muscle depth at the sternal vertebrae was significantly deeper (almost 55 mm at 12 months of age) than 16 mm at thoracic and 16 mm at lumbar vertebrae at 12 and 8 months of age, respectively. No subcutaneous fat depth measurements were recorded in the lumbar vertebrae (0.00?±?0.00) and the thoracic (0.00?±?0.00) regions in all sex groups. However, fourth and fifth sternal vertebrae showed considerably deeper amount of subcutaneous fat suitable for taking fat measurements as age increases (2.07?±?0.23 mm females, 1.50?±?0.43 mm intact males and 1.80?±?0.38 mm castrates) at 12 months of age. All correlations between live and carcass ultrasound measurements and also between ultrasound carcass and ruler measurements were very high (r ²?=?0.96 to 1.00) for all the sexes indicating that live ultrasound measurements are suitable for use in this meat breed. More research is needed to evaluate the relationships between live ultrasonic measurements and carcass yield in the different sexes of Tswana goat kids.     

Estimation of sheep carcass traits by ultrasound technology

Real-time ultrasound technology offers the possibility of estimating carcass characteristics in live animals and represents a potential method for selection of breeding stocks. A total of 745 live lambs born during 2001–2003 into two flocks was used to estimate rib muscle and fat depth by ultrasound. Lambs came from 559 ewes and 97 rams of a fat-tailed breed, known as the ‘Barbarine’ in North Africa. Ultrasound measurements of external fat thickness (UFD) and muscle (UMD), taken at the 12–13th rib and palpation of body conditions (loin and tail scores) were made for 150 days until lambs 520 days old of lamb ages. Main results showed that UMD and UFD had the same trend as live weights from 150 to 240 days old. They decreased from 150 to 200 days old, and then increased. The same trend was seen for loin and tail scores. Average differences in live weights between male and female lambs were 1, 3 and 6 kg at 30, 90 and 120 days old, respectively. The highest muscle depth for males was reached at day 180 and the lowest fat depth was recorded between 180 and 200 days. Average loin scores became greater for males than females from 240 days of age. Male lambs had greater tail scores at all ages, from 150 to 520 days old. Differences became greater for ages more than 180 days, showing that males have a tendency to store more fat in their tails than females. Phenotypic correlation was 0.70 between muscle depth and loin scores, indicating that, at 180 days old, the Barbarine breed has more muscle and less fat. The optimum slaughter age was defined between 180 and 200 days old, producing carcasses with more muscle and less fat. Regression equations estimating carcass traits (UMD, UFD) at 180 and 240 days old were computed.     

Commercial adaptation of ultrasonography to predict pork carcass composition from live animal and carcass measurements.

Live animal and carcass data were collected from market barrows and gilts (n = 120) slaughtered at a regional commercial slaughter facility to develop and test prediction equations to estimate carcass composition from live animal and carcass ultrasonic measurements. Data from 60 animals were used to develop these equations. Best results were obtained in predicting weight and percentage of boneless cuts (ham, loin, and shoulder) and less accuracy was obtained for predicting weight and ratio of trimmed, bone-in cuts. Independent variables analyzed for the live models were live weight, sex, ultrasonic fat at first rib, last rib, and last lumbar vertebra, and muscle depth at last rib. Independent variables for the carcass models included hot carcass weight, sex of carcass, and carcass ultrasonic measurements for fat at the first rib, last rib, last lumbar vertebra, and muscle depth at last rib. Equations were tested against an independent set of experimental animals (n = 60). Equations for predicting weight of lean cuts, boneless lean cuts, fat-standardized lean, and percentage of fat-standardized lean were most accurate from both live animal and carcass measurements with R2 values between .75 and .88. The results from this study, under commercial conditions, suggest that although live animal or carcass weight and sex were the greatest contributors to variation in carcass composition, ultrasonography can be a noninvasive means of differentiating value, especially for fat-standardized lean and weight of boneless cuts.     

Evaluation of equations to predict body composition in Nellore bulls

The equations developed by Hankins and Howe (1946, HH), Marcondes et al. (2010, M10), Marcondes et al. (in press, M11) and Valadares Filho et al. (2006, V6) were evaluated to predict the body composition from the 9–10–11th rib cut in Nellore bulls. The evaluated equations estimated the physical and the carcass chemical composition, the empty body chemical composition and the noncarcass chemical composition. Thirty-seven Nellore bulls (14±1 months old initially) with shrunk body weight of 259±24.9 kg were used in this experiment. The bulls were randomly divided into three groups: five bulls to the reference group, four bulls were fed at maintenance level and twenty-eight bulls were fed ad libitum. The bulls fed ad libitum were separated into four groups, one of which was slaughtered every 42 days. The diet was composed of corn silage and concentrate (55:45). After slaughter, the 9–10–11th rib cut was dissected into muscle, fat and bone fractions. The remaining carcass was similarly dissected. The others parameters that were evaluated as partial predictors included the empty body weight, the dressing percentage, the visceral fat percentage, the organ and viscera percentage and the composition of the noncarcass components. The values estimated with prediction equations were compared to the observed values. The equations obtained by M11 predicted correctly the carcass physical composition. However, the muscle and fat tissues were under- and overestimated, respectively, by HH. Some constituents of the noncarcass components can be predicted from equations developed by M10. The equations obtained by M10 predicted correctly the carcass and empty body chemical composition. The carcass water was underestimated by HH. The equations by V6 did not predict the carcass or empty body chemical composition. The carcass physical and chemical composition and empty body chemical composition can be predicted from the composition of 9–10–11th rib cut by equations obtained by Marcondes et al., 2010 and MarcondesPlease complete and update the reference given here (preferably with a DOI if the publication data are not known): Marcondes et al. (in press). For references to articles that are to be included in the same (special) issue, please add the words ‘this issue’ wherever this occurs in the list and, if appropriate, in the text. et al., while the composition of these components cannot be predicted by Hankins and Howe (1946) and Valadares Filho et al. (2006) in Nellore bulls.     

Evaluation of columbia, USMARC-Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: III. Prefabrication carcass traits and organ weights

To evaluate terminal-sire breeds, harvest BW, prefabrication carcass measurements, and organ weights were evaluated over 3 yr for 518 crossbred wether lambs (ovis aries). Lambs were produced by single-sire matings of 22 Columbia, 22 USMARC-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouillet ewes. Lambs were raised to weaning under an extensive western rangeland production system and finished in a feedlot on a high-energy finishing diet. Wethers were randomly assigned to be harvested at an average BW of 54.4, 61.2, or 68.0 kg and then transported to The Ohio State University abattoir for harvest. Wether BW was recorded before transport (off-test BW) and before harvest. Prefabrication carcass measurements and organ weights were recorded either after harvest or after an approximate 24-h chill. At comparable numbers of days on feed, Suffolk-sired lambs had heavier (P < 0.01) off-test BW, harvest BW, HCW, chilled carcass weight (CCW), and kidney weights than lambs sired by the other breeds. Suffolk-sired lambs had more (P < 0.01) kidney-pelvic fat than did Columbia-sired lambs; Composite- and Texel-sired lambs were intermediate and did not differ (P > 0.06) from the other crossbred lambs. Texel- and suffolk-sired lambs had larger lm area and greater conformation scores than Columbia-sired lambs (P < 0.03). Texel-sired lambs had greater (P < 0.01) body wall thickness, quality grades, and leg scores than Columbia-sired lambs. Composite- and Suffolk-sired lambs did not differ from each other or from lambs sired by any other breed for body wall thickness (P > 0.18) and were intermediate for quality grades and leg scores. Sire breed did not affect (P > 0.05) shipping shrink, dressing percentage, pelt weight, liver weight, and fat depth. Adjusting data to a comparable off-test BW or CCW modified sire breed rankings for some measurements. Texel-sired lambs were equal or superior to lambs sired by other breeds for HCW, CCW, dressing percentage, pelt weight, LM area, quality grade, and leg and conformation scores. However, Texel-sired lambs also had values for kidney-pelvic fat weight, fat depth, and body wall thickness that were equal to or greater than those of lambs sired by the other breeds, indicating increased fatness at comparable BW. Producers can use these results to select terminal-sire sheep breeds that will complement their production system and improve market lamb value.     

Genetic and environmental effects on carcass characteristics of Southdown x Romney lambs: II. Genetic and phenotypic variation

Approximately 4,400 crossbred lambs from Southdown sires and Romney ewes were slaughtered at approximately 18, 23, and 28 wk of age over a 16-yr period. Live weights, carcass measurements, and chemical percentages were analyzed to estimate genetic and phenotypic parameters. Heritabilities of postweaning weights and gains were about .20. Heritabilities of fat and water percentages were about .35 adjusted for age. Heritability of kidney fat percentage was .53. Heritabilities of fat depth and muscle measurements ranged from .21 to .37. Crutch depth (h2 = .73) and cannon bone length (h2 = .74) were the most highly heritable carcass measurements. The genetic correlation between carcass fat and fat-free weight was .47 when lambs were slaughtered at a constant age. Fat-free weight was nearly uncorrelated with percentages of fat, water, and protein when lambs were slaughtered at the same age. Carcass measurements increased accuracy of selection for fat-free weight at a constant age very little compared with using only carcass weight. However, this does not mean that additional measurements are useless. The addition of carcass measurements to the selection criteria would result in correlated responses in chemical composition that more closely resembled direct selection for fat-free weight. Carcass weight would be of little value when used by itself to reduce fat weight adjusted for carcass weight. Direct measurement of carcass composition resulted in 1.6 to 2.6 times more predicted response for reduced fat weight than any combination of carcass weight and one fat depth measurement.     

Estimation of the carcass composition from a cross-section of the rib-loin from crossbred Japanese Black × Limousin F2 cattle by computer image analysis

The carcass composition of crossbred Japanese Black × Limousin F2 cattle was examined in order to find an accurate carcass composition equation. The test animals included 17 steers and 17 heifers. The 28 image measurements from the area encircling the vertical line to the thoracic vertebra and the line from the thoracic vertebra between the sixth and seventh rib‐bones were measured by computer image analysis. The relationships between the 29 parameters that added the carcass left side weight of the animal and the carcass composition were suggested. The carcass composition included muscle weight, muscle ratio, fat weight and fat ratio. The carcass composition from steers was estimated by an equation composed of these three or four parameters (R² = 90.80%, 79.30%, 90.75% and 73.70%, respectively). The selected parameters were measured without cutting the thoracic vertebra. The carcass composition from heifers was estimated by an equation composed of two to four parameters (R² = 96.15%, 90.98%, 93.60% and 88.22%, respectively). The parameters for the estimation of the muscle and fat weight, and muscle and fat ratio are very similar. Furthermore, the equations using the parameters could estimate the carcass composition from the Japanese Black × Limousin cattle resource population.     

Muscle metabolism and real-time ultrasound measurement of muscle and subcutaneous adipose tissue growth in lambs fed diets containing a beta-agonist

Rambouillet X Finn crossbred wether lambs were evaluated for differences in longissimus muscle cross-sectional area and overlaying subcutaneous adipose tissue thickness resulting from the use of the beta-agonist clenbuterol. Treatment groups received 0 and 2 ppm clenbuterol in the diet for approximately 40 d prior to slaughter. Longissimus muscle cross-sectional area and fat depth over the 12th-13th rib juncture were measured by real-time ultrasound before and during administration of the compound. At slaughter, muscle metabolism in vitro and carcass characteristics were measured. Based on comparisons with an initial-kill group of sheep, longissimus muscle cross-sectional area increased in control sheep by 12% (P greater than .05) over the 40-d experimental period, and increased in clenbuterol-fed sheep by 48% (P less than .05). Conversely, subcutaneous fat thickness increased significantly in the control sheep (88%) during this period, but was unchanged in the clenbuterol-fed animals. Warner-Bratzler shear force values of cooked longissimus samples from clenbuterol-fed sheep were significantly greater than shear force values in cooked samples from control lambs; this was not correlated with the extractable neutral lipid content of the muscle. Simple linear regression between ultrasound and carcass measurements of longissimus muscle cross-sectional area and subcutaneous fat thickness yielded correlation coefficients of .80 and .64, respectively. A significantly greater amount of net glycogen synthesis from [U-14C]glucose was observed in longissimus muscle strips from clenbuterol-fed animals than in muscle strips from control sheep.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prediction of physical and chemical body compositions of purebred and crossbred Nellore cattle using the composition of a rib section

The goal of this research was to develop empirical equations to predict chemical and physical compositions of the carcass and the body using the composition of the 9th- to 11th-rib section (rib(9-11)) and other measurements. A database (n = 246) from 6 studies was developed and comprised 37 bulls (BU), 115 steers (STR), and 94 heifers (HF), of which 132 were Nellore (NEL), 76 were NEL × Angus crossbreds (NA), and 38 were NEL × Simmental crossbreds (NS). The right half carcass and the rib(9-11) from the left half carcass were analyzed for ether extract (EE), CP, and water. The remaining components were chemically analyzed to determine the composition of the body. A stepwise procedure was used to determine the variable inclusion in the regression models. The variables included were EE in the rib(9-11) (EER; %), CP in the rib(9-11) (CPR; %), water in the rib(9-11) (WR; %), visceral fat (VF; %; KPH and mesenteric fats), organs plus viscera (OV; %), carcass dressing percentage (CD; %), cold carcass weight (kg), and empty BW (EBW; kg). No sex or breed effects were found on EE and CP compositions of the carcass (C(EE) and C(CP), respectively; %); the equations were as follows: C(EE) = 4.31 + 0.31 × EER + 1.37 × VF [n = 241; R(2) = 0.83; mean square error (MSE) = 4.53] and C(CP) = 17.92 + 0.60 × CPR - 0.17 × CD (n = 238; R(2) = 0.50; MSE = 1.58). Breed affected water content in the carcass (C(W), %); the equations were as follows: C(W) = 48.74 + 0.28 × WR - 0.017 × EBW for NEL; C(W) = 46.69 + 0.32 × WR - 0.017 × EBW for NA; and C(W) = 38.06 + 0.48 × WR - 0.017 × EBW for NS (n = 243; R(2) = 0.67; MSE = 5.17). A sex effect was found on body chemical EE composition (BW(EE)); the equations were as follows: BW(EE) = 2.75 + 0.33 × EER + 1.80 × VF for BU; BW(EE) = 1.84 + 0.33 × EER + 1.91 × VF for STR; and BW(EE) = 4.77 + 0.33 × EER + 1.28 × VF for HF (n = 243; R(2) = 0.89; MSE = 3.88). No sex or breed effects were found on CP composition in the body (BW(CP)); the equation was as follows: BW(CP) = 14.38 + 0.24 × CPR (n = 240; R(2) = 0.59; MSE = 1.06). A sex effect was found for body water content (BW(W)); the equations were as follows: BW(W) = 38.31 + 0.33 × WR - 1.09 × VF + 0.50 × OV for BU; BW(W) = 45.67 + 0.25 × WR - 1.89 × VF + 0.50 × OV for STR; and BW(W) = 31.61 + 0.47 × WR - 1.06 × VF + 0.50 × OV for HF (n = 241; R(2) = 0.81; MSE = 3.84). The physical carcass composition indicated a breed effect on all components and a sex effect for fat in the carcass. We conclude that body and carcass compositions can be estimated with rib(9-11) for purebred and crossbred NEL animals, but specific equations have to be developed for different groups of animals.     

Assessment of carcass composition based on ultrasonic measurements and EUROP conformation class of live lambs

Summary The aim of this study was to investigate the accuracy of ultrasound muscle (UMD) and fat depth (UFD) measurements as well as live EUROP conformation class (LEUROP) in predicting carcass composition and conformation in lambs. Measurements of 5993 lambs were analysed applying a multi‐trait animal model and the Restricted Maximum Likelihood (REML) method to obtain variance components for scanning live weight (SLW), UMD, UFD and LEUROP. The data were field records of Finnsheep and a small number of lambs from other breeds, from over 30 flocks between 1997 and 1999. The lambs were measured close to 120 days of age. Scanning was behind the last rib and at the third lumbar vertebra. Just before slaughter, scanning was repeated with a subset of lambs, whose half carcasses (n = 224) were dissected for lean, fat and bone. The UMD (third lumbar) and SLW together accounted for 51% of the variance in lean weight in the model in Finnsheep. The UFD alone explained 21% of the variance in lean percentage, UMD was a better predictor for carcass conformation than LEUROP. The estimates of heritability for SLW, UMD, UFD and LEUROP were 0.44, 0.46, 0.39 and 0.27 (with standard errors of 0.03 each), respectively. High positive genetic correlations, ranging from 0.49 to 0.69, were obtained between the four traits. Selection for UMD has resulted in genetic improvement of 0.06 mm/year (1%) in a Finnsheep nucleus flock. Conformation score of live animals could be considered to be included in the breeding programme if uniformity of assessment is assured by continued training.     

Predicting tissue distribution and partitioning in terminal sire sheep using x-ray computed tomography

The utility of x-ray computed tomography (CT) scanning in predicting carcass tissue distribution and fat partitioning in vivo in terminal sire sheep was examined using data from 160 lambs representing combinations of 3 breeds (Charollais, Suffolk, and Texel), 3 genetic lines, and both sexes. One-fifth of the lambs were slaughtered at each of 14, 18, and 22 wk of age, and the remaining two-fifths at 26 wk of age. The left side of each carcass was dissected into 8 joints with each joint dissected into fat (intermuscular and subcutaneous), lean, and bone. Chemical fat content of the LM was measured. Tissue distribution was described by proportions of total carcass tissue and lean weight contained within the leg, loin, and shoulder regions of the carcass and within the higher-priced joints. Fat partitioning variables included proportion of total carcass fat contained in the subcutaneous depot and intramuscular fat content of the LM. Before slaughter, all lambs were CT scanned at 7 anatomical positions (ischium, midshaft of femur, hip, second and fifth lumbar vertebrae, sixth and eighth thoracic vertebrae). Areas of fat, lean, and bone (mm(2)) and average fat and lean density (Hounsfield units) were measured from each cross-sectional scan. Areas of intermuscular and subcutaneous fat were measured on 2 scans (ischium and eighth thoracic vertebra). Intramuscular fat content was predicted with moderate accuracy (R(2) = 56.6) using information from only 2 CT scans. Four measures of carcass tissue distribution were predicted with moderate to high accuracy: the proportion of total carcass (R(2) = 54.7) and lean (R(2) = 46.2) weight contained in the higher-priced joints and the proportion of total carcass (R(2) = 77.7) and lean (R(2) = 55.0) weight in the leg region. Including BW in the predictions did not improve their accuracy (P > 0.05). Although breed-line-sex combination significantly affected fit of the regression for some tissue distribution variables, the values predicted were changed only trivially. Within terminal sire type animals, using a common set of prediction equations is justified. Tissue distribution and fat partitioning affect eating satisfaction and efficiency of production and processing; therefore, including such carcass quality measures in selection programs is increasingly important, and CT scanning appears to provide opportunities to do so.     

The prediction of percentage of fat in pork carcasses

Forty-seven market-weight pigs were slaughtered in order to determine percentage of chemical fat and in an attempt to determine an easily obtainable and inexpensive method to predict this value. The hams and 8-9-10 rib loin sections were removed from the left side of each carcass and dissected into subcutaneous and seam fat, individual muscles, skin and bone. Weights and chemical analysis were determined for each component. Numerous weights, measurements and specific gravity were determined on the carcass, ham and loin section of each pig. Percentage of chemical fat of each ham, loin section and carcasses was determined and correlated with the various weights and measurements taken. Stepwise regression was used to develop prediction equations using carcass data, specific gravity, ham or loin measurements or various combinations of these as dependent variables. The single best indicator of the decimal fraction of chemical fat in the pork carcass was determined to be specific gravity of the carcass half, the prediction equation using this variable had an R-square of .64. By adding 10th rib fat thickness to this equation, the R-square increased to .72. The best equation using carcass variables included 10th rib fat and marbling (R-square = .67). The loin section proved to be an accurate indicator of composition; ham measures were not as accurate as specific gravity and carcass measurements for predicting percentage of carcass fat. This research suggests that the percentage of chemical fat in the pork carcass can be predicted by an easy and inexpensive means.     

Carcass composition and meat quality of equally mature kids and lambs

Carcass composition and meat quality attributes of 55 suckling kids (27 males and 28 females) and 57 suckling lambs (28 males and 29 females) of Portuguese native breeds were investigated. These suckling kid and lamb meats are European meat quality labels produced according to "Cabrito de Barroso- PGI" and "Borrego Terrincho-PDO" specifications, respectively. Female kids were slaughtered at 9.1 +/- 0.36 kg of BW, and male kids were slaughtered at 10.4 +/- 0.37 kg of BW, corresponding to 20.1 and 17.7% of maturity, respectively. Female lambs were slaughtered at 8.6 +/- 0.53 kg of BW, and male lambs were slaughtered at 9.9 +/- 0.23 kg of BW, corresponding to 19.9 and 17.1% of maturity, respectively. At 24 h postmortem, various yield and quality measurements were collected. The left sides of the carcasses were dissected into muscle, subcutaneous fat, intermuscular fat, and bone. Final pH, instrumental color (L*, a*, b*), carcass measurements, and kidney knob and pelvic fat were also determined. Samples of LM were taken from the lumbar and thoracic cuts for intramuscular and meat quality determinations. At 72 h postmortem, a sample of LM was used for cooking losses and Warner-Bratzler shear force determination. Suckling lambs had greater dressing proportion than suckling kids (P < 0.01). Carcass fatness was not affected by species (P > 0.05), but females had greater kidney knob and pelvic fat proportion than males (P < 0.01). Lambs had greater proportions of the highly valued leg cut and lower proportions of shoulder, anterior rib, and neck cuts than kids. Dissection results indicated that kid carcasses had greater muscle content and lower dissected fat and bone than lambs. Kids had greater (P < 0.001) muscle ultimate pH value than lambs (5.8 +/- 0.02 vs. 5.6 +/- 0.02). Males had greater (P < 0.05) muscle ultimate pH value than females (5.7 +/- 0.02 vs. 5.6 +/- 0.02). The kid meat was significantly lighter (P < 0.05) and less yellow (P < 0.001) than the lamb meat. Kids presented less cooking losses (P < 0.001) than lambs, and shear force value was significantly greater (P < 0.01) in lamb meat. The kid meat had significantly more moisture (P < 0.001) and less intramuscular fat content (P < 0.001) than lambs. At this maturity stage, there were significant differences on both carcass and meat quality attributes of suckling kids and lambs, possibly due to inherent differences between species.     

Effect of live weight gain of steers during winter grazing: I. Feedlot performance, carcass characteristics, and body composition of beef steers

Two experiments were conducted to examine the effect of previous BW gain during winter grazing on subsequent growth, carcass characteristics, and change in body composition during the feedlot finishing phase. In each experiment, 48 fall-weaned Angus x Angus-Hereford steer calves were assigned randomly to one of three treatments: 1) high rate of BW gain grazing winter wheat (HGW), 2) low rate of BW gain grazing winter wheat (LGW), or 3) grazing dormant tallgrass native range (NR) supplemented with 0.91 kg/d of cottonseed meal. Winter grazing ADG (kg/d) for HGW, LGW, and NR steers were, respectively, 1.31, 0.54, 0.16 (Exp. 1) and 1.10, 0.68, 0.15 (Exp. 2). At the end of winter grazing, four steers were selected randomly from each treatment to measure initial carcass characteristics and chemical composition of carcass, offal, and empty body. All remaining steers were fed a high-concentrate diet to a common backfat end point. Six steers were selected randomly from each treatment for final chemical composition, and carcass characteristics were measured on all steers. Initial fat mass and proportion in carcass, offal, and empty body were greatest (P < 0.001) for HGW, intermediate for LGW, and least for NR steers in both experiments. Live BW ADG and gain efficiency during the finishing phase did not differ (P = 0.24) among treatments, but DMI (% of mean BW) for NR and LGW was greater (P < 0.003) than for HGW steers. Final empty-body composition did not differ (P = 0.25) among treatments in Exp. 1. In Exp. 2, final carcass and empty-body fat proportion (g/kg) was greater (P < 0.03) for LGW and NR than for HGW steers. Accretion of carcass fat-free organic matter was greater (P < 0.004) for LGW than for HGW and NR steers in Exp. 1, but did not differ (P = 0.22) among treatments in Exp. 2. Fat accretion in carcass, offal, and empty body did not differ (P = 0.19) among treatments in Exp. 1, but was greater (P < 0.05) for LGW and NR than for HGW steers in Exp. 2. Heat production by NR steers during finishing was greater (P < 0.02) than by HGW steers in Exp. 1 and 2. Differences in ADG during winter grazing and initial body fat content did not affect rate of live BW gain or gain efficiency during finishing. Feeding steers to a common backfat thickness end point mitigated initial differences in carcass and empty-body fat content. However, maintenance energy requirements during finishing were increased for nutritionally restricted steers that were wintered on dormant native range.     

Effect of dietary betaine on nutrient utilization and partitioning in the young growing feed-restricted pig

The purpose of this study was to examine the effects of dietary betaine over a range of concentrations (between 0 and 0.5%) on growth and body composition in young feed-restricted pigs. Betaine is associated with decreased lipid deposition and altered protein utilization in finishing pigs, and it has been suggested that the positive effects of betaine on growth and carcass composition may be greater in energy-restricted pigs. Thirty-two barrows (36 kg, n = 8 pigs per group) were restrictively fed one of four corn-soybean meal-skim milk based diets (18.6% crude protein, 3.23 Mcal ME/kg) and supplemented with 0, 0.125, 0.25, or 0.5% betaine. Feed allotment was adjusted weekly according to BW, such that average feed intake was approximately 1.7 kg for all groups. At 64 kg, pigs were slaughtered and visceral tissue was removed and weighed. Carcasses were chilled for 24 h to obtain carcass measurements. Subsequently, one-half of each carcass and whole visceral tissue were ground for chemical analysis. Linear regression analysis indicated that, as betaine content of the diet was elevated from 0 to 0.5%, carcass fat concentration (P = 0.06), P3 fat depth (P = 0.14) and viscera weight (P = 0.129) were decreased, whereas total carcass protein (P = 0.124), protein deposition rate (P = 0.98), and lean gain efficiency (P = 0.115) were increased. The greatest differences over control pigs were observed in pigs consuming 0.5% betaine, where carcass fat concentration and P3 fat depth were decreased by 10 and 26%, respectively. Other fat depth measurements were not different (P > 0.15) from those of control pigs. In addition, pigs consuming the highest betaine level had a 19% increase in the carcass protein:fat ratio, 23% higher carcass protein deposition rate, and a 24% increase in lean gain efficiency compared with controls. Dietary betaine had no effects (P > 0.15) on growth performance, visceral tissue chemical composition, carcass fat deposition rate, visceral fat and protein deposition rates, or serum urea and ammonia concentrations. These data suggest that betaine alters nutrient partitioning such that carcass protein deposition is enhanced at the expense of carcass fat and in part, visceral tissue.