Carcass Shape Research Articles

Evaluation of carcass traits, meat quality and the expression of lipid metabolism-related genes in different slaughter ages and muscles of Taihang black goats.

This study was conducted to investigate the effect of slaughter age on carcass traits, meat quality, and the relative mRNA levels of lipid metabolism-related genes in different muscles of Taihang black goats. In this study, the triceps brachii (TB), longissimus dorsi (LD) and gluteus (GL) muscles of 15 grazing Taihang black goats slaughtered at the age of 2, 3, and 4 (designated as 2-year-old, 3-year-old, and 4-year-old, respectively) were collected. The differences in carcass shape, meat quality, amino acid composition and lipid metabolism gene expression among Taihang black goats of different ages and from different plant parts were compared. Compared with goats at other ages, goats slaughtered at the age of 4 had greater live and carcass weights, meat weights, bone weights and skin areas (p<0.05). LD in the 4-years-old had the lowest cooking loss and moisture content. The crude protein content in the LD of 2-year-old was significantly greater than that in the other age group, and at the age of 2, the LD had the highest crude protein content than TB and GL. The highest fat content was in LD, followed by TB, for goats slaughtered at the age of 4. Eight out of 9 essential amino acids had higher content in the TB compared with other muscles, regardless of age. The total essential amino acid content was highest in the 4-year-old and lowest in the GL muscle at the age of 3. The sterol regulatory element-binding protein-1c (SREBP-1c) and adipose triglyceride lipase (ATGL) genes were significantly more abundant in the TB muscle than in the other muscles for goats slaughtered at the age of 2. At the age of 4, the ATGL and peroxisome proliferator-activated receptor γ (PPARγ) genes were significantly more abundant in the GL than in the LD, while the fatty acid synthase (FAS) genes were significantly less abundant in the GL than in the other muscles. Similarly, compared with those in goats of other ages, the relative mRNA expression levels of the FAS and heart-type fatty acid binding protein (H-FABP) genes in goats slaughtered at the age of 4 were the highest, and the relative mRNA expression of the PPARγ gene was the lowest (p<0.05). The relative mRNA expression of the H-FABP and FAS genes was positively correlated with the intramuscular fat (IMF) content, while the relative mRNA expression levels of the PPARγ and ATGL genes was negatively correlated with the IMF content. Overall, a better nutritional value was obtained for TB from 4-year-old goats, in which the total essential amino acid and fat contents were greater than those of other muscles. The comprehensive action of lipid metabolism genes was consistent with that of the IMF content, among which the FAS, H-FABP, PPARγ, and ATGL genes had positive and negative effects on the process of IMF deposition in Taihang black goats.

Relationships among carcass shape, tissue composition, primal cuts and meat quality traits in lambs: A PLS path modeling approach

Abstract This study aimed to understand the relations among measures of carcass shape, of carcass tissue characterization, and of commercial cuts of hair sheep lambs in order to assess the ability of images obtained through video image analysis (VIA) to consistently describe meat quality. Information on 67 cold carcasses were submitted to the partial least squares path modeling (PLS-PM) method regarding the manifest variables (MV) that made up the latent variables (LV) of carcass shape (SHAPE), meat quality (QUALI_MEAT), carcass tissue composition (TISSUE_CARCASS), and commercial cut composition (TISSUE_ PRIMALCUTS). Three models that differed according to SHAPE characteristics were evaluated. Model VIA1, with MVs of total projection of carcass and regions, was considered the suitable validated model and was able to predict meat quality characteristics only for the aspects of cooking loss and shear force. It enables establishing categories for carcass classification that directly determine meat juiciness and tenderness from the latent variables considered from carcass shape and description of tissue carcass and primal cuts.

Effects and interactions of myostatin and callipyge mutations: I. Growth and carcass traits.

Objectives were to document effects of the Texel myostatin mutation (MSTN) on growth and carcass traits and also test whether or not interactions with the callipyge mutation (CLPG) could be detected. Twelve rams heterozygous at both loci on the two different chromosomes were mated to 215 terminal-sire type composite crossbred ewes genotyped as non-carriers for both loci. A total of 365 lambs were born, 362 of those were genotyped and 236 lambs contributed carcass data to estimate effects and interactions among the four genotype combinations produced. The four genotype combinations were defined as follows: ++/++ for wild-type at both loci; ++/C+ for wild-type at MSTN and heterozygous at CLPG; M+/++ for heterozygous at MSTN and wild-type at CLPG; and M+/C+ for heterozygous at both loci. The two independently segregating sire-derived alleles represent different breed-of-origin contrasts at each locus (Texel vs. composite origin for MSTN and Dorset vs. Texel origin for CLPG). Birth weight was recorded on all lambs, and subsequent body weights were adjusted to 56 (weaning), 70, and 140 d of age. Within sire-sex-genotype subgroups, naturally reared lambs were assigned to one of eight slaughter groups accounting for variation in birth date. Lambs were serially slaughtered at weekly intervals, 30 lambs per group, from roughly 26 to 33 wk of age. In addition to standard carcass traits, subjective leg scores were assigned and widths of carcasses were measured at the widest points of the shoulder and rump. Differences in birth weight were detected (P < 0.01) for the combination of the two loci and birth type, with single-born differences among genotypes exceeding differences among twin born progeny. Those interaction differences among genotypes were not as important at weaning (P = 0.36). Impact on growth rate differences among the genotypes during the post-weaning period were variable and dependent on sex of the lamb (P < 0.01). A synergistic interaction between MSTN and CLPG was observed for leg muscling scores (P < 0.05) but no other measures of carcass shape were affected. One copy of MSTN had a more modest impact on fat deposition and muscle conformation than did CLPG and did not interact (all values P > 0.20). Although some non-additive interactions that vary by trait and sex were detected, in general the data are consistent with the two mutations acting on muscle growth through independent pathways.

Evaluation of Columbia, USMARC Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: VII. Accuracy of ultrasound predictors and their association with carcass weight, yield, and value.

Use of lamb BW or chilled carcass weights (CCW), live-animal ultrasound or direct carcass measurements of backfat thickness (BF; mm) and LM area (LMA; cm(2)), and carcass body wall thickness (BWall; mm) to predict carcass yield and value was evaluated using 512 crossbred lambs produced over 3 yr by mating Columbia, U.S. Meat Animal Research Center Composite, Suffolk, and Texel rams to adult Rambouillet ewes. Lambs were harvested at 3 BW endpoints within each year. The predictive value of 3 to 5 additional linear measurements of live-animal or carcass size and shape was also evaluated. Residual correlations (adjusted for effects of year, breed, and harvest group) between ultrasound and direct measurements were 0.69 for BF and 0.65 for LMA. Increasing ultrasound or carcass LMA had positive effects (P < 0.001) on yield of chilled carcass (i.e., on dressing percentage) and, at comparable CCW, on weight of high-value cuts (rack, loin, leg, and sirloin) before trimming (HVW), weight of trimmed high-value cuts (trimmed rack and loin and trimmed boneless leg and sirloin; TrHVW), and carcass value before (CVal) and after (TrCVal) trimming of high-value cuts. By contrast, ultrasound and direct measures of BF had positive effects on yields of CCW and on HVW and CVal but large negative effects on TrHVW and TrCVal. After adjusting for BW at scanning, increases of 1 mm in ultrasound BF or 1 cm(2) in ultrasound LMA were associated with changes of US$-0.32 (P < 0.10) and $1.62 (P < 0.001), respectively, in TrCVal. Carcass BWall was generally superior to carcass BF as a predictor of TrHVW and TrCVal. Carcass LMA was superior to ultrasound LMA but carcass BF was inferior to ultrasound BF for prediction of carcass yield and value. Increasing LMA thus would be expected to improve carcass yield and value. Addition of linear measurements of live-animal or carcass size and shape to the prediction model reduced residual SD (RSD) for TrHVW and TrCVal by 0.4 to 2.2%, but subsequent removal of ultrasound or direct measures of BF and LMA from the prediction model increased RSD by 7.4 to 12.2%. Measurements of CCW, LMA, BF, and BWall would thus be appropriate to support programs for value-based marketing of lamb carcasses and are superior to systems based only on measurements of size and shape in unribbed carcasses.

Evaluation of Columbia, U.S. Meat Animal Research Center Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: VI. Measurements of live-lamb and carcass shape and their relationship to carcass yield and value1,2

Linear measurements on live lambs and carcasses can be used to characterize sheep breeds and may have value for prediction of carcass yield and value. This study used 512 crossbred lambs produced over 3 yr by mating Columbia, U.S. Meat Animal Research Center (USMARC) Composite, Suffolk, and Texel rams to adult Rambouillet ewes to assess sire-breed differences in live-animal and carcass shape and to evaluate the value of shape measurements as predictors of chilled carcass weight (CCW), weight of high-value cuts (rack, loin, leg, and sirloin; HVW), weight of trimmed high-value cuts (trimmed rack and loin and trimmed, boneless leg and sirloin; TrHVW), and estimated carcass value before (CVal) and after trimming of high-value cuts (TrCVal). Lambs were produced under extensive rangeland conditions, weaned at an average age of 132 d, fed a concentrate diet in a drylot, and harvested in each year in 3 groups at target mean BW of 54, 61, and 68 kg. Canonical discriminant analysis indicated that over 93% of variation among sire breeds was accounted for by the contrast between tall, long, less-thickly muscled breeds with greater BW and CCW (i.e., the Columbia and Suffolk) compared with shorter, more thickly muscled breeds with smaller BW and CCW. After correcting for effects of year, harvest group, sire breed, and shipping BW, linear measurements on live lambs contributed little to prediction of CCW. Similarly, after accounting for effects of CCW, linear measurements on live animals further reduced residual SD (RSD) of dependent variables by 0.2 to 5.7%, with generally positive effects of increasing live leg width and generally negative effects of increasing heart girth. Carcass measurements were somewhat more valuable as predictors of carcass merit. After fitting effects of CCW, additional consideration of carcass shape reduced RSD by 2.1, 3.6, 9.5, and 2.2% for HVW, TrHVW, CVal, and TrCVal, respectively. Effects of increasing carcass leg width were positive for HVW, TrHVW, and TrCVal. We also observed positive effects of increasing carcass length on TrCVal and negative effects of increasing cannon bone length on HVW and CVal. Increasing shoulder width had positive effects on CVal but negative effects on TrHVW. Differences in lamb and carcass shape were significantly associated with carcass yield and value, but the additional accuracy associated with use of these measurements was modest relative to that achieved from use of only shipping BW or CCW.

Evaluating the effects of the c.*1232G > A mutation and TM-QTL in Texel × Welsh Mountain lambs using ultrasound and video image analyses

The c.*1232G > A (MM) mutation in the myostatin gene and TM-QTL are two muscle-enhancing polymorphisms found on Chr 2 and Chr 18, respectively, in Texel sheep. Previous studies on purebred lambs and crossbred lambs out of Mule ewes showed that MM was associated with increased muscle mass and decreased fat content whereas heterozygous TM-QTL lambs had increased loin muscle (M. longissimus lumborum, MLL) depth as measured by ultrasound and increased MLL weight. Welsh Mountain ewes, like Mule ewes, contribute significantly to UK slaughter lamb production from the UK sheep industry's stratified structure. Therefore, this study aimed to evaluate the direct effects of MM and TM-QTL in the genetic background of Texel×Welsh Mountain lambs.Four Texel sires, all MM carriers and two TM-QTL carriers, were used to inseminate Welsh Mountain ewes. Of the 175 lambs born, 130 could be classified for TM-QTL genotype [107 non-carriers (+/+), 23 heterozygous carriers (TM/+)] and 172 for MM genotype [15 non-carriers (+/+), 129 heterozygous carriers (MM/+), 28 homozygous carriers (MM/MM)]. All lambs were weighed at 8 and ∼23weeks of age and were ultrasound scanned before being slaughtered at ∼24weeks of age. All carcasses were graded for conformation and fat class, based on Meat and Livestock Commission (MLC) classification scores, and then scanned using a video image analysis (VIA) system to predict weight of carcass primal cuts and trimmed primal cuts, muscularity traits and carcass shape traits.Carrying two copies of MM was associated with a significant positive effect on 8 weeks weight, a negative effect on ultrasound fat depth and a substantial decrease in MLC-fat score. Two copies of MM also had a strong positive impact on VIA-estimated weight of the hind leg, chump and loin primal cuts, as well as the muscularity of the hind leg and loin regions with greater loin muscle width, depth and area. Homozygous MM carrier lambs had significantly wider carcasses across the shoulders, breast and hind legs and greater areas of the back view of the carcass when measured by VIA. Leg and carcass compactness were also significantly associated with the presence of two copies of MM. However, lambs carrying a single copy of MM were not significantly different to non-carriers in any of the traits measured. TM-QTL significantly increased ultrasound muscle depth and TM-QTL carriers had significantly greater loin muscle width and area measurements. Carcass weight did not differ significantly between genotypic classes for MM or TM-QTL. These results agree in general with other reports of the effects of MM and TM-QTL, in both direction and magnitude, on carcass traits.

Estimation of genetic trends in French Large White pigs from 1977 to 1998 for growth and carcass traits using frozen semen12

Genetic trends for growth, feed efficiency, composition, and morphometry of carcasses were estimated in a French Large White (LW) pig population using frozen semen. Two groups of pigs were produced by inseminating LW sows with either stored, frozen semen from 17 LW boars born in 1977 or with semen from 23 LW boars born in 1998. In each group, 15 males and 90 females were randomly chosen and mated to produce approximately 1,000 pigs/group. These pigs were performance tested with individual ADFI and serial BW and backfat thickness measurements, slaughtered at 105 kg of BW, and measured for carcass traits. The data were analyzed using mixed linear animal models, including the fixed effect of the experimental group (offspring of 1977 or 1998 boars), the random effect of the additive genetic value of each animal, and, when significant, the fixed effects of sex, fattening batch, and slaughterhouse, the linear regression on BW, and the random effect of the common environment of birth litter. For each trait, the genetic trend was estimated as twice the difference between the 2 experimental groups. Results showed moderately favorable trends for on-test ADG (3.7 +/- 1.3 g/d per year) and feed conversion ratio (-0.014 +/- 0.005 kg/kg per year) in spite of a tendency toward an increase in ADFI (7.6 +/- 4.7 g/yr). A strong reduction in carcass fatness (-0.35 +/- 0.07 mm/yr for carcass average backfat thickness) and a large improvement in carcass leanness (0.31 +/- 0.10 mm(2)/yr and 0.41 +/- 0.08%/yr for loin eye area and carcass muscle content, respectively) were observed. Carcass shape measurements (back and leg length, back width, muscle thickness of hind limbs) were not affected by selection. Serial measurements of BW and backfat thickness showed that the major part of the genetic gains occurred during late growth and that the reduction in the backfat layer was more pronounced in the rear than in the front part of the carcass. The use of frozen semen appears to be a powerful practice to thoroughly investigate changes attributable to selection.

Prediction of fat, muscle and value in Norwegian lamb carcasses using EUROP classification, carcass shape and length measurements, visible light reflectance and computer tomography (CT)

One hundred and twenty carcasses were sampled to compare different techniques or methods for prediction of lamb carcass composition and value. Four methods that are used at the Norwegian Meat Research Centre, Animalia, were selected. These were the basic EUROP classification, the advanced EUROP classification using carcass shape and length measurements, visible light reflectance probing (GP) and Computer Tomography (CT). The different technologies were tested using an iterative approach, selecting calibration and validation data sets from the 120 carcasses randomly, where 90 carcasses were used for calibration, and 30 for validation. The best prediction models were obtained using CT, with respect to prediction error and correlation between predicted and measured value of carcass fat and muscle (in kg), and value (in NOK). Due to high cost and low operating speeds of CT, optical probing (GP) may be the second best solution of the technologies used in this study, combined with a CT dissection reference as an alternative to manual dissection.

Protein rich ingredients from fish waste for sheep feeding

Fish wastes, including viscera, heads, tails and skins, were ground and mixed with 10% molasses and inoculated with a starter culture made of Lactobacillus plantarum. The inoculated mixture was incubated at 25°C for 10 days, for a biopreservation/biotransformation by fermentation. During the fermentation period, changes in nutritional quality and biochemical properties (pH, dry matter, ash, total and volatile nitrogen and lipids) were monitored as well as microbiological determinations, including standard plate count, coliforms and Clostridium. Results indicated that the ph decreased considerably and remained constant at 3.8 after 8 days. Total nitrogen, decreased non protein nitrogen and total volatile nitrogen increased. The microbiological characteristics showed a drastic decrease of coliforms and Clostridium counts in 8 days. Two trials and a control were carried out and the final fish waste silage product was used in feeding sheep in two trials of 5 sheep each. The fish silage was added to ground barley and wheat bran* in two proportions respectively (40% barley, 25% fish silage and 35% wheat bran) and (40% barley, 50% fish silage and 10 % wheat bran). The control diet was the conventional feed adopted in the region (40% barley, 60% wheat bran*). The weight gain was followed up for 9 weeks. The results indicated that trial feeding studies with young sheep using formulas containing fish silage showed a net increase in weight above controls as well as a good enhancement of meat characteristics and carcass shape. Keys words: Fish wastes, molasses, barley, wheat bran, Lactobacillus plantarum, fish silage, sheep feeding.

Carcass composition and meat quality differences between pasture-reared ewe and ram lambs

Comparisons were made of carcass and meat quality characteristics of pasture-raised Texel-cross ewe ( n = 269) and ram ( n = 275) lambs between 5 and 8 months of age with an average carcass weight of 17.2 kg. Carcass assessment was based on linear dimensions and dissection of a leg into muscle, fat and bone, and meat quality measurements were made on M. semimembranosus and M. longissimus. At a set carcass weight, ewe lambs had higher dressing percentages (2%), shorter carcasses (0.7 cm), and heavier leg cuts (35 g) ( P < 0.01) than males. At the same leg weight, legs of ewe lambs were fatter than males (subcutaneous plus intermuscular fat; 11.2% vs 9.6%; P < 0.001), whereas legs of ram lambs contained significantly more muscle and bone than females ( P < 0.001). Leg muscle to bone ratio (4.7 vs 4.4) and muscularity were higher for females than males ( P < 0.001). However, the relationship between leg muscle to bone ratio and muscularity was not the same between the sexes, and for any given muscularity value the muscle to bone ratio of ram lambs was lower than females. As a result, if carcass lean meat yield is predicted from a measure of carcass shape, such as muscularity, lean meat yields will be overestimated for males and underestimated for females. Meat quality was lower in ram lambs than in females ( P < 0.001) as shown by higher Warner-Bratzler shear values (peak value 109.8 vs 97.0 N for M. Semimembranosus), higher ultimate meat pH values, and lower redness ( a ∗) and lightness ( L ∗, for the longissimus muscle only) values ( P < 0.001). It is concluded that significant differences between ewe and ram lambs do exist for many carcass and meat quality traits, but for most quality traits the differences are small.

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: IV. Survival, growth, and carcass traits of F1 lambs1,2

The objectives of this study were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), and dam breed (Composite III and Northwestern whiteface) on survival, growth, carcass, and composition traits of F1 lambs. Effects of mating season (August, October, and December) were estimated for survival and growth traits. Data were collected on 4,320 F1 lambs sired by 102 purebred rams over 3 yr. Birth weight was recorded on all lambs, and subsequent BW were adjusted to 56 (weaning), 70, and 140 d of age (n = 3,713, 3,654, and 3,579 observations, respectively). Survival of dam-reared progeny (n = 4,065) to weaning was recorded. Each year, wethers from October matings were slaughtered in three groups at 25, 29, and 33 wk of age to obtain carcass data (n = 546). In addition to standard carcass traits, resistive impedance measurements were recorded on the warm carcass to predict lean mass. Dam breed (P = 0.37) did not influence lamb survival to weaning, but sire breed (P < 0.05) was important. Romanov-sired lambs excelled in survival rate to weaning (94.1%), followed by Finn-sheep (93.0%), Texel (90.7%), Dorset (90.0%), and Montadale (89.1%) sired progeny. Lower (P < 0.01) postweaning growth rate was observed for Texel (267 g/d) and Finnsheep (272 g/d) sired progeny than for Dorset (285 g/d), Montadale (282 g/d), and Romanov (278 g/d) sired progeny. Sire breed and dam breed were generally significant for most carcass traits. Breed differences in distribution of carcass fat and carcass shape were detected; however, carcass composition was similar for all sire breeds when compared at a constant carcass weight. When evaluated at a constant 12th-rib fat depth, carcasses of lambs from Finnsheep, Romanov, and Texel sires produced 1 to 1.5 kg less (P < 0.001) predicted lean mass per lamb than carcasses of lambs from Dorset and Montadale sires. These experimental results provide information about the direct breed effects for survival, growth, and carcass traits of these breeds and their potential use in crossbreeding systems.

The use of X-ray computer tomography for measuring the muscularity of live sheep

AbstractPotential measures of muscularity derived from X-ray computer tomography (CT) were assessed using data for 160 sheep (50 Suffolk males, 50 Suffolk females, 40 Texel males and 20 Charollais males). One-fifth of the lambs within each breed and sex were slaughtered at each of 14, 18 or 22 weeks of age and two-fifths slaughtered at 26 weeks. All lambs were CT scanned prior to slaughter with longitudinal and cross-sectional scans taken at three positions along the body [5th lumbar vertebra (LV5), mid-shaft of the femur (FEM) and ischium (ISC)]. After slaughter, linear measurements of side length (SL) and M. longissimus thoracis et lumborum (LTL) width (A) and depth (B) (12/ 13th thoracic vertebra) were taken on the left side of the carcass. The side was dissected and femur length (FL), the weight of three muscles surrounding the femur (M3) and the total muscle weight in the side (TM) were recorded. Five muscularity measures were calculated for the carcass. Two for the LTL muscle (A/SL, B/SL), one for the hind leg (√M3/FL3) and one for the whole carcass (√TM/SL3).Correlations between spine length measured on the CT longitudinal scans and side length measured on the carcass were high (&gt; 0·62), while correlations between measurements of LTL width and depth on the carcass with those on the LV5 scan were moderate (&gt; 0·41). CT measures of muscularity were derived using linear measurements taken on CT scans together with a prediction of total muscle weight using CT tissue areas. Correlations between CT measures and dissection measures of LTL and whole carcass muscularity were moderate to high (0·33–0·54). Correlations between the dissection measure and four CT measures of hind leg muscularity were higher (0·48-0·60). These results clearly show that good in vivo measures of muscularity can be obtained for sheep by using measurements that can be taken on CT scans. This will be a useful tool for selection programmes aiming to improve sheep carcass shape, particularly those already using CT scanning to increase rates of genetic improvement in lean tissue growth.

Relationships between beef carcass shape and muscle to bone ratio

Relationships between muscularity and muscle to bone ratio were investigated for beef carcasses of several breeds and crosses, and three genders using data from Bristol and Alberta. Side dissection data in terms of muscle, fat and bone weights were used to calculate muscle to bone ratios (MtoB) and muscularity indexes (MUSC) for the whole side or for the region around the femur bone. Highly significant breed and gender effects on MtoB and MUSC were shown for both the Bristol and the Alberta data sets, but the group differences for MtoB were not the same as those for MUSC despite the fact that these two characteristics were closely correlated. For both sets of data, for example, MUSC values at a common muscle plus bone weight were significantly higher for carcasses of bulls than heifers, but similarly adjusted MtoB values were generally higher for carcasses of heifers than bulls. Differences among breed groups were mainly in a similar direction for MUSC and MtoB, but the size of the differences varied widely. For example, relative to the Friesian, the Jersey breed had a significantly higher MtoB but a significantly lower MUSC, and carcasses of double-muscled bulls had a femur-region MtoB that was 19.2% greater than that of a group of Shorthorn-cross carcasses, but a MUSC that was only 1.7% higher. These findings show that because of the inconsistent relationships between muscularity and muscle to bone ratio among different classes of beef carcasses, lean meat yield cannot always be predicted without bias if measures of carcass shape are used as indicators of muscle to bone ratio.

Some carcass characteristics of Alpine kids under intensive versus semi-intensive systems of production in France

The effect of system of production (intensive versus semi-intensive) on some slaughter and carcass traits of Alpine male kids was evaluated. Data adjusted to a common age, indicated that management system had no significant effect ( P>0.05) on carcass shape (carcass conformation and compactness and gigot conformation) and external fat score. Kids raised under the intensive management (IM) had heavier slaughter and carcass weights and large carcass width ( P<0.01). Their dressing percentage and internal fat score were higher ( P<0.05).

Video image analysis for on-line classification of lamb carcasses

AbstractVideo image analysis (VIA), carcass shape and colour data were collected for 1211 lambs of known gender, breed type and carcass weight over a 1-week period using the VIAscan® system developed by the Australian Meat Research Corporation. Classification data (thickness of soft tissue over the 12th rib (GR measurement) and subjective conformation scores on a five-point scale of the leg, loin and shoulder) were assessed by an Agriculture and Agri-Food Canada grader after carcasses had chilled at 5°C for 3 to 6 h. Dissections into saleable meat yield (no. = 58) were performed after carcasses had chilled an additional 24 h. The timing of this study, which was dependent on availability of the VIA equipment, influenced the age and type of lambs available for analysis. The majority of lambs evaluated were wool-breed wethers, age &gt; 10 months, of average GR (15·7 (s.d. 0·2) mm) and muscle conformation (3·0, s.d. 0·1). VIA improved the prediction of saleable meat yield (R2 = 0·71, residual s.d. = 14g/kg) compared with the current classification system (R2 = 0·52, residual s.d. = 18 g/kg). Although prediction ofGR measurement by VIA resulted in a large residual error (residual s.d. = 2·4 mm), the proportion of waste fat (perirenal and subcutaneous) and bone dissected from the carcass was accurately predicted (R2 = 0·62, residual s.d. = 11 g/kg). Proportions of leg (R2 = 0·71, residual s.d. = 7 g/kg) and shoulder (R2 = 0·62, residual s.d. = 9 g/kg) primals were also accurately predicted by VIA, although there were no significant predictors for the proportion of the loin (P &gt; 0·15). VIA improved the prediction of saleable meat yield compared with the current classification system. However collection of additional data including some from extremely lean or well muscled animals would be required before VIA could be recommended to classify lamb carcasses

Automatic assessment of sheep carcasses by image analysis

AbstractThe commercial value of animal carcasses depends not only on their weight but also on their composition and shape (termed conformation). This is usually assessed subjectively by a skilled inspector. In this paper an attempt is described to assess the saleable meat yield of sheep carcasses by automatic digital image analysis. A low-cost system based on a still video camera and a personal computer was used. The results indicate that better prediction of saleable meat yield can be obtained using objective measures of carcass shape than from subjective conformation scores. Information from the intensities of colour components was not found to be useful, possibly due to difficulties with lighting and image quality. Recommendations are made for implementing a practical system.

The effect of oestrogenic agents on live-weight gain, carcass composition, reproductive function and tissue residues in intensively reared beef bulls given cereal-based diets

ABSTRACTThe use of oestradiol-17β was evaluated in cereal-based beef production on 14 farms with 450 bulls. Half of the bulls were implanted subcutaneously in the ear with a silastic rubber implant containing 45 mg oestradiol-17β Representative bulls close to mean weight for each group were selected for slaughter on the same day at the end of the trial for carcass measurements. The remaining bulls were slaughtered at the farmers' discretion. Where possible, slaughter live weight (208 bulls), carcass weight (412) and European Economic Community carcass classification (353) were recorded. Implanted bulls had higher gains only in the first 3 months (+76 (s.e. 17) g/day; P &lt; 0·001) and had heavier carcasses with the extra weight in the forequarter (+2·3 (s.e. 0·61) kg; P &lt; 0·001), better carcass shape (+0·9 (s.e. 0·3) points; P &lt; 0·01) and more subcutaneous fat in the thin flank (+1·3 (s.e. 0·6) g/kg; P &lt; 0·05). Implanted bulls selected for slaughter by farmers were not slaughtered earlier, but killed out better (+0·7 (s.e. 0·3) g/kg; P &lt; 0·05) and had heavier carcasses (+4·6 (s.e. 0·5) kg; P &lt; 0·01) of better shape (+0·8 (s.e. 0·3) points; P &lt; 0·05).The use of zeranol was evaluated in cereal beef production on 15 farms with 385 bulls. Half received 36 mg zeranol which was repeated after 6 months. Forty-four bulls were selected for detailed carcass assessment as above. Implanted bulls had daily gains 0·06 (s.e. 0·01) kg greater (P &lt; 0·001) than controls. Farmers chose to slaughter implanted bulls 8·3 (s.e. 3·8) days earlier (P &lt; 0·05) at only marginally heavier weights (+4·8 (s.e. 3·1) kg; P = 0·08). More implanted bull carcasses were distributed in better shape and higher fat classes (P &lt; 0·01). There were no significant differences in fore- and hindquarter and thin-flank tissue proportions. Oestradiol treatment marginally decreased testis weight in slaughtered bulls whereas zeranol treatment had no significant effect although epididymal weight was decreased in zeranol treated bulls. There were no clear effects of either treatment on testicular structure, but both oestradiol and zeranol caused a degree of disruption to the epididymal epithelium. Zeranol concentrations in treated animal tissues were not significantly different from those in control animals.

The effect of oestradiol 17β on liveweight gain and carcass composition of intensively reared cereal beef bulls

Oestradiol 17β (Compudose-365 ) is widely used as a growth promoter in steers and the daily gain response is well known. However, for bull beef production the efficiency of the hormone implant is not so well researched, particularly in Great Britain, where there is not yet a product licence for use in bulls. Work in the U.S.A. has shown that Oestradiol 17β implants in bulls stimulate daily gain and improve carcass shape, but at the same time increasing subcutaneous fat levels (Johnson et al, 1984). The trial described here was designed to study the effect of Oestradiol 17β under a range of farm conditions in Great Britain.Sixteen groups of bulls on 14 farms, totalling 450 bulls, were selected. Fourteen of the groups were wholly British Friesian, the remainder Friesian/Holstein or Limousin cross. The bulls were weighed at 3-4 months of age and paired by weight. One of each pair was implanted subcutaneously in the ear with a silastic rubber implant containing 45 mg Oestradiol 17β (Compudose-365, Elanco Products Ltd.). The bulls were weighed after three and six months (mean 108 and 180 days respectively), and about half were weighed within four days of slaughter (mean 222 days).

Selecting finished stock for slaughter

With the emphasis on producing finished stock to a required specification, it is important that the producer should be able to estimate the potential carcass characteristics of his stock.MLC has produced two slide tape presentations for use with farming audiences which take a step-by-step approach to this subject. The slide tapes concentrate on the assessment of fat level, which is very much under the control of the producer. Carcass shape, on the other hand, is strongly related to breed and is far less manipulatable by short-term management.

Development of Carcass Shape in Pekin and Muscovy Ducks

Male and female White Muscovy and White Pekin ducks were killed at weekly intervals from hatching to 10 weeks. Their carcasses were dissected and lengths of skeletal units and weights of representative muscles were recorded. Data were analysed for allometric (proportional) growth relative to keel length or unilateral breast muscle weight using Huxley's allometric growth equation. Wing bones tended to grow proportionally faster than keel length; this was most evident in Muscovies, possibly because of their greater powers of flight. Skull and leg bones grew proportionally more slowly than keel length. Biceps brachii, semitendinosus, and gastrocnemius muscles grew proportionally more slowly than breast muscles. The existing pattern of allometric growth in duck carcasses suggests that the response of total muscle mass to selection for increased breast muscle mass will be greater in Muscovies relative to Pekins with similar breast improvement.