Included Carcass Weight Research Articles

Partial ablation of uropygial gland effect on carcass characteristics of Akar Putra chicken

This study evaluated the effect of partial uropygialectomy (PU) on carcass traits of male and female Akar Putra chickens. Sixty chicks of each sex were evenly distributed into 5 treatment groups with 3 replicates per group containing 4 males and 4 females each, and reared for 12 wk. Homogeneity of the groups was satisfied with regard to the parity. Experimental treatments consisted of a control treatment (T1), and partial ablation of the uropygial gland was applied on the second, third, fourth, and fifth treatments at 3, 4, 5, and 6 wk of age, respectively. The chickens were fed ad libitum the same diets (1 to 13d: starter; 14 d to slaughter: finisher). On the last d of the experiment, 12 birds were randomly selected from each treatment group (2males and 2 females per replicate) and slaughtered to determine carcass characteristics, which included carcass weight, dressing percentage with or without eating giblets, and the relative weights of heart, liver, gizzard, thighs, wings, breast, back, and neck. From the results of the study, it was shown that the partial ablation of the uropygial gland at all ages had certain dependent effects concerning some carcass parameters, as shown by higher breast and back relative weights in males and breast relative weight in females. As a consequence, a positive effect also was noticed regarding the carcass morphology in terms of the increase in dressing percentage with or without eating giblets thus leading to an increase in the body weight and carcass weight. Furthermore, the best result was obtained in the second treatment when PU was applied at 3 wk of age compared with other experimental groups. Moreover, the current study provides a novel and economic alternative to enhance the body performance of poultry in general and Akar Putra chicken particularly.

Genetic differences based on a beef terminal index are reflected in future phenotypic performance differences in commercial beef cattle

The increased demand for animal-derived protein and energy for human consumption will have to be achieved through a combination of improved animal genetic merit and better management strategies. The objective of the present study was to quantify whether differences in genetic merit among animals materialised into phenotypic differences in commercial herds. Carcass phenotypes on 156 864 animals from 7301 finishing herds were used, which included carcass weight (kg), carcass conformation score (scale 1 to 15), carcass fat score (scale 1 to 15) at slaughter as well as carcass price. The price per kilogram and the total carcass value that the producer received for the animal at slaughter was also used. A terminal index, calculated in the national genetic evaluations, was obtained for each animal. The index was based on pedigree index for calving performance, feed intake and carcass traits from the national genetic evaluations. Animals were categorised into four terminal index groups on the basis of genetic merit estimates that were derived before the expression of the phenotypic information by the validation animals. The association between terminal index and phenotypic performance at slaughter was undertaken using mixed models; whether the association differed by gender (i.e. young bulls, steers and heifers) or by early life experiences (animals born in a dairy herd or beef herd) was also investigated. The regression coefficient of phenotypic carcass weight, carcass conformation and carcass fat on their respective estimated breeding values (EBVs) was 0.92 kg, 1.08 units and 0.79 units, respectively, which is close to the expectation of one. Relative to animals in the lowest genetic merit group, animals in the highest genetic merit group had, on average, a 38.7 kg heavier carcass, with 2.21 units greater carcass conformation, and 0.82 units less fat. The superior genetic merit animals were, on average, slaughtered 6 days younger than their inferior genetic merit contemporaries. The superior carcass characteristics of the genetically elite animals materialised in carcasses worth €187 more than those of the lowest genetic merit animals. Although the phenotypic difference in carcass traits of animals divergent in terminal index differed statistically by animal gender and early life experience, the detected interactions were generally biologically small. This study clearly indicates that selection on an appropriate terminal index will produce higher performing animals and this was consistent across all production systems investigated.

Genome-wide Association Study to Identify Quantitative Trait Loci for Meat and Carcass Quality Traits in Berkshire.

Meat and carcass quality attributes are of crucial importance influencing consumer preference and profitability in the pork industry. A set of 400 Berkshire pigs were collected from Dasan breeding farm, Namwon, Chonbuk province, Korea that were born between 2012 and 2013. To perform genome wide association studies (GWAS), eleven meat and carcass quality traits were considered, including carcass weight, backfat thickness, pH value after 24 hours (pH24), Commission Internationale de l’Eclairage lightness in meat color (CIE L), redness in meat color (CIE a), yellowness in meat color (CIE b), filtering, drip loss, heat loss, shear force and marbling score. All of the 400 animals were genotyped with the Porcine 62K SNP BeadChips (Illumina Inc., USA). A SAS general linear model procedure (SAS version 9.2) was used to pre-adjust the animal phenotypes before GWAS with sire and sex effects as fixed effects and slaughter age as a covariate. After fitting the fixed and covariate factors in the model, the residuals of the phenotype regressed on additive effects of each single nucleotide polymorphism (SNP) under a linear regression model (PLINK version 1.07). The significant SNPs after permutation testing at a chromosome-wise level were subjected to stepwise regression analysis to determine the best set of SNP markers. A total of 55 significant (p<0.05) SNPs or quantitative trait loci (QTL) were detected on various chromosomes. The QTLs explained from 5.06% to 8.28% of the total phenotypic variation of the traits. Some QTLs with pleiotropic effect were also identified. A pair of significant QTL for pH24 was also found to affect both CIE L and drip loss percentage. The significant QTL after characterization of the functional candidate genes on the QTL or around the QTL region may be effectively and efficiently used in marker assisted selection to achieve enhanced genetic improvement of the trait considered.

Allelic frequencies and association with carcass traits of six genes in local subpopulations of Japanese Black cattle.

Marker-assisted selection (MAS) is expected to accelerate the genetic improvement of Japanese Black cattle. However, verification of the effects of the genes for MAS in different subpopulations is required prior to the application of MAS. In this study, we investigated the allelic frequencies and genotypic effects for carcass traits of six genes, which can be used in MAS, in eight local subpopulations. These genes are SCD, FASN and SREBP1, which are associated with the fatty acid composition of meat, and NCAPG, MC1R and F11, which are associated with carcass weight, coat color and blood coagulation abnormality, respectively. The frequencies of desirable alleles of SCD and FASN were relatively high and that of NCAPG was relatively low, and NCAPG was significantly associated with several carcass traits, including carcass weight. The proportions of genotypic variance explained by NCAPG to phenotypic variance were 4.83 for carcass weight. We thus confirmed that NCAPG is a useful marker for selection of carcass traits in these subpopulations. In addition, we found that the desirable alleles of six genes showed no negative effects on carcass traits. Therefore, selection using these genes to improve target traits should not have negative impacts on carcass traits.

Genetic relationships of carcass traits with retail cut productivity of hanwoo cattle.

This study aimed to estimate genetic correlation between carcass grading and retail productivity traits and to estimate the correlated response on retail productivity traits through selection for carcass grading traits in order to assess the efficacy of indirect selection. Genetic parameters were estimated with the data from 4240 Hanwoo steers using mixed models, and phenotypes included carcass weight (CWT), back fat thickness (BFT), eye muscle area (EMA), marbling (MAR), and estimated lean yield percentage (ELP) as the carcass grading traits, and weight and portion of retail cuts (RCW and RCP), trimmed fats (TFW and TFP) and trimmed bones (TBW and TBP) as the lean productivity traits. The CWT had positive genetic correlations with RCW (0.95) and TFW (0.73), but its genetic correlation with RCP was negligible (0.02). The BFT was negatively correlated with RCP (−0.63), but positively correlated with TFW and TFP (0.77 and 0.70). Genetic correlations of MAR with TFW and TFP were low. Among the carcass grading traits, only EMA was positively correlated with both RCW (0.60) and RCP (0.72). The EMA had a relatively strong negative genetic correlation with TFW (−0.64). The genetic correlation coefficients of ELP with RCP, TFW, and TFP were 0.76, −0.90, and −0.82, respectively. These correlation coefficients suggested that the ELP and EMA might be favorable traits in regulating lean productivity of carcass.

Genetic analysis of an F2 intercross between two strains of Japanese quail provided evidence for quantitative trait loci affecting carcass composition and internal organs

The purpose of this study was to identify genomic regions, quantitative trait loci (QTL), affecting carcass traits on chromosome 1 in an F2 population of Japanese quail. For this purpose, two white and wild strains of Japanese quail (16 birds) were crossed reciprocally and F1 generation (34 birds) was created. The F2 generation was produced by intercrossing of the F1 birds. Phenotypic data including carcass weight, internal organs and carcass parts were collected on F2 animals (422 birds). The total mapping population (472 birds) was genotyped for 8 microsatellite markers on chromosome 1. QTL analysis was performed with interval mapping method applying the line-cross model. Significant QTL were identified for breast weight at 0 (P < 0.01), 172 (P < 0.05) and 206 (P < 0.01), carcass weight at 91 (P < 0.05), carcass fatness at 0 (P < 0.01), pre-stomach weight at 206 (P < 0.01) and uropygial weight gland at 197 (P < 0.01) cM on chromosome 1. There was also evidence for imprinted QTL affecting breast weight (P < 0.01) on chromosome 1. The proportion of the F2 phenotypic variation explained by the significant additive, dominance and imprinted QTL effects ranged from 1.0 to 7.3%, 1.2 to 3.3% and 1.4 to 2.2%, respectively.

Differential expressions of HSP27 and HSP70 is induced in the longissimus dorsi muscle of fattening pigs fed a fermented carrot by-product

We investigated whether a fermented feed supplemented with carrot by-product is associated with body weight and meat quality in pigs, as well as whether it affects the expression of heat shock proteins (HSPs). The chemical composition of the fermented feed was 4% crude protein, 4% crude fat, 2% crude fibre, 0.2% phosphorus and 0.04% calcium. The daily weight gain and finished body weights of pigs fed the treated diet, which supplemented with the fermented diet including carrot by-product, were approximately 175 g and 5 kg greater, respectively, than those that received the basal diet. The transcriptional levels of HSP27 and HSP70 in the longissimus dorsi muscles of pigs fed the treated diet were lower than those that received the basal diets. The correlation coefficients (CORRs) between the expressions of HSP and meat traits including carcass weight, quality grade, crude fat, water holding capacity and drip loss showed strong negative effects. The treated diet reduces the expression levels of HSP27 and HSP70 in pigs, and this is associated with increased daily weight gain, final body weight and higher meat quality as measured by carcass weight, quality grade and water-holding capacity.

평창지역 거세출하우 자료를 이용한 유전모수 추정

The objective of this study was to establish genetic evaluation systems with carcass data collected by 68 individual farms from 2007 to 2011 in Pyeongchang area of Kangwon province. All the possible of environment effects were corrected by analysis of variance (ANOVA) to estimate more accurate genetic parameters. Heritabilities and genetic correlations were estimated from carcass data collected from Hanwoo steers(n=10,441) born in Pyeongchang region from 2005 to 2008. Traits evaluated included carcass weight (CWT), eye muscle area (EMA), back fat thickness (BF) and marbling score (MS). As for the mean value and standard deviation for carcass traits, CWT, EMA, BF and MS were 424.5, 92, 13.7 and 5.7. Parameters were estimated using a multiple trait animal model and derivative-free restricted maximum likelihood procedures. Estimated heritabilities for CWT, EMA, BF and MS were 0.30, 0.21, 0.42 and 0.42, respectively. Genetic correlation of CWT with EMA, BF and MS were estimated to 0.24, 0.36 and 0.07, respectively. Genetic correlation of EMA with BF and MS was -0.27 and 0.61, respectively.

Genome-Wide Association Study Identifies Loci and Candidate Genes for Body Composition and Meat Quality Traits in Beijing-You Chickens

Body composition and meat quality traits are important economic traits of chickens. The development of high-throughput genotyping platforms and relevant statistical methods have enabled genome-wide association studies in chickens. In order to identify molecular markers and candidate genes associated with body composition and meat quality traits, genome-wide association studies were conducted using the Illumina 60 K SNP Beadchip to genotype 724 Beijing-You chickens. For each bird, a total of 16 traits were measured, including carcass weight (CW), eviscerated weight (EW), dressing percentage, breast muscle weight (BrW) and percentage (BrP), thigh muscle weight and percentage, abdominal fat weight and percentage, dry matter and intramuscular fat contents of breast and thigh muscle, ultimate pH, and shear force of the pectoralis major muscle at 100 d of age. The SNPs that were significantly associated with the phenotypic traits were identified using both simple (GLM) and compressed mixed linear (MLM) models. For nine of ten body composition traits studied, SNPs showing genome wide significance (P<2.59E−6) have been identified. A consistent region on chicken (Gallus gallus) chromosome 4 (GGA4), including seven significant SNPs and four candidate genes (LCORL, LAP3, LDB2, TAPT1), were found to be associated with CW and EW. Another 0.65 Mb region on GGA3 for BrW and BrP was identified. After measuring the mRNA content in beast muscle for five genes located in this region, the changes in GJA1 expression were found to be consistent with that of breast muscle weight across development. It is highly possible that GJA1 is a functional gene for breast muscle development in chickens. For meat quality traits, several SNPs reaching suggestive association were identified and possible candidate genes with their functions were discussed.

High throughput analyses of epistasis for swine body dimensions and organ weights

High throughput analyses were performed to detect epistatic QTL in 17 body dimension and organ weight traits from a large F(2) pig population derived from a White Duroc and Erhualian intercross. The analyses used a nested test framework to handle multiple tests and a combined search algorithm to map epistatic QTL with empirical genome-wide thresholds derived via prior permutation. Alternative statistical models (e.g. including vs. excluding carcass weight as a covariate) were tested to develop an in-depth understanding of the role of epistasis in these kinds of traits. Epistasis signals were detected in only two or three traits under each statistical model studied. The interaction component of each pair of epistatic QTL explained a small proportion (0.7 to 2.1%) of the phenotypic variance in general. About half of the detected epistatic QTL pairs involved one of the two major QTL on porcine chromosomes 7 and 4. In those traits, the Erhualian allele consistently increased the phenotypes for the chromosome 7 QTL but decreased them for the chromosome 4 QTL. Models including carcass weight as covariate detected epistasis in body dimension traits whereas those excluding carcass weight found epistasis in organ weight traits. In addition, the epistasis results suggested that a QTL on chromosome 14 could be important for a number of organ weight traits. Using the high-throughput analysis tool to examine different statistical models was essential for the generation of a complete picture of epistasis in a whole category of traits.

돼지의 마이코플라즈마성 폐렴과 경제형질간의 상관관계 연구

ABSTRACT Pneumonia is one of the important diseases in commercial pig. In order to delineate the relationships with pneumonia and productions traits, five different economic traits including carcass weight (CW), backfat thickness (BF), meat quality (MQ), carcass characteristics (CC) and pork belly thickness (PB) were measured in 6,362 commercial pigs. Significant differences were observed in all the traits with pneumonia (P<0.01). Carcass weight and backfat thickness decreased significantly as the symptom of pneumonia was severed (P<0.01). Also, when the pneumonia was severed, the carcass characteristics and meat quality became worse compared with normal unaffected animals (P<0.01). In case of pork belly thickness, the significant decrease was observed in pneumonia infected animals compared with normal animals (P<0.01). Based on this study, the pneumonia infection affects most of the important economic traits in pigs and it is ultimately needed to pay more attention to prevent this disease.(

The effects of selection indices for sustainable hill sheep production on carcass composition and muscularity of lambs, measured using X-ray computed tomography

A multi-trait selection index designed to improve the overall economic performance of hill sheep, including both maternal and lamb traits, has been developed and tested in a selection experiment over 7 years. Two versions of the index were tested, with different economic weights applied to the traits, on two different hill farms: one version including maternal and growth traits; the other version with additional breeding goals of carcass weight, fatness and conformation scores. Responses to selection, using both versions of the index, suggest that improvements are being made in overall index score and lamb growth. This study investigated the indirect effects of these selection indices on lamb carcass composition and muscularity traits, as measured using X-ray computed tomography (CT) scanning. A total of 499 lambs from the two hill farms were CT scanned at weaning (approximately 120 days of age). Approximately half of the lambs from each farm were from the selection line (S, animals with highest index scores selected for breeding), while the other half were from a control line (C, animals with average index scores selected). Composition and muscularity traits were estimated on each lamb from CT data and differences between genetic lines investigated, within farm, using restricted maximum likelihood analyses, adjusting for either live weight or age. Results showed that the selection index without carcass traits produced lambs with carcass composition that was not significantly different to control lambs at a given live weight or age. Including carcass traits in the index resulted in lambs with no compositional differences (except for a slight increase in bone) at a set age compared with controls. At a given live weight however, selection lambs had less fat and lower carcass weights and killing-out percentage. Muscularity (3-D muscle shape) and muscle area shape (2-D) were not improved as a result of selection on either version of the index (including carcass weight and grades in the breeding goals or not) and, at a fixed live weight, muscularity in hind leg and lumbar regions tended to be higher in the C line. To accelerate changes in carcass composition and muscularity within the context of a multi-trait selection index for hill sheep, consideration should therefore be given to including objective CT-derived carcass traits in the index in addition to the Meat and Livestock Commission (MLC) carcass grades or ultrasound measurements.

Predicting yields of high priced trimmed beef cuts by means of carcass weight and visual assessments of fat cover and conformation

The total and individual trimmed meat yield of six hind quarter cuts and one fore quarter cut were estimated for 200 carcasses from animals of mixed origin with regard to breed, sex and feeding regimen. The linear models included carcass weight and visual assessment of fatness and conformation by means of seven fat and five conformation classes. Amount of variation accounted for (R2) was the most favourable for total yield (87.3%) and the least favourable for the rib-eye cut (43.5%). Carcass weight contributed to most of the variation accounted for and had a positive effect on the yield for all the cuts. Fat score and conformation score were significant in the models of all cuts and total yield except for the rump, and contributed at least 10 percentage points to the R2-value for the topside, thick flank, loin, rib-eye and fillet. Fat score had a negative effect on trimmed yield of all cuts except for the loin, which could be attributed to less trimming compared to other cuts. Conformation score had positive effects on the yield of all cuts except for the rump (non significant), fillet and thick flank. Fat score had the largest proportional effect (to size of the cut) on topside and thick flank, which both contain significant fat deposits. Conformation score had the largest proportional effect on the loin and rib-eye, which is probably due to the synergistic effect of fatness and conformation on the conformation score in this region. The accuracy of estimation of total yield for the purpose of awarding premiums to yield categories was considered to be good when the residual standard deviation of the estimated yield was compared with the standard deviation of the trial sample. However, separating cuts into different weight categories was less accurate and varied among cuts, which suggests that more information is needed for more reliable models before accurate individual yields of cuts can be predicted in practice. Keywords : Conformation score; fat score; premiums; saleable meat South African Journal of Animal Sciences Vol. 35 (3) 2005: pp.195-205

Comparison of three rabbit breeds on performance, carcasses characters and meat chemical composition

Sixty rabbits from three breeds (Local, Albino, Angora) were used to determine the impact of the breeds specificity on the performance parameters, some of the carcass characters and meat composition of deferent breeds. The rabbits were equally divided into 3 groups. Each batch contain both sexes of four weeks old. The rabbits were fed a standard ration consisting 16% CP, 2380 KCal as ametabolizable energy for sixteen weeks. At the termination of the experiment, all rabbits were weighed, sacrificed. Various carcass measurements were conducted, including carcass weight, edible offal w.t, dressing percentage. Whole chemical analysis of rabbits meat were abo couied out. Significant increase (p>0.5) of finished w.t, weekly body gain of the local breed were obtained which were 1296; 1151; 1187; 61; 51 and 53 gm for the local, Albino and Angora breeds, respectively. Concerning feed conversion efficiency, the local breed showed better feed utilization than Angora breed, while similar results were found to that of Albino breed which were 6, 7, 5.8 kg ration/ kg body gain. Carcass w.t (650 gm) and dressing percentage (55%) of local breed were higher than other breeds which were 554 and 555 gm, 52% and 52% for Albino and Angora, respectively. In all the breeds, there were no significant difference in chemical composition of the meat, except for ether extract which were higher (p>0.5) for Angora than other breed. Ether extract was records to be 5.3%, 4% and 4.2% for Angora, local and Albino breeds, respectively. Depending upon productivity index and carcass characters, it can be concluded that the local breed is better than Albino or Angora.

Live weight, body size and carcass characteristics of young bulls of fifteen European breeds

A total of 436 young bulls from fifteen Western European breeds, including beef, dairy and local types from five countries, were studied to assess variability in live weight, live weight gain, body measurements and carcass traits. Animals were logged indoors, and fed a diet based on concentrate and straw offered ad libitum from 9 months of age to slaughter at 15 months of age. The weight, body length, height at withers and pelvis width, of the animals were recorded at 9, 12 and 15 months of age. After slaughter, 15 carcass variables were recorded, including carcass weight, EU classification scores, morphological measurements and dissection data. Data were analysed by GLM, regression and principal component analysis procedures. Significant differences were found between breeds for all variables studied, however, the body size measurements and the carcass traits were more useful to discriminate among cattle breeds, than either live weight or daily gain. With respect to the body size and carcass traits the studied breeds could be grouped as: – Specialized beef breeds, comprising Piemontese, Asturiana de los Valles, Pirenaica, Limousin, South Devon, Charolais and Aberdeen Angus, all of which were characterized by high muscularity, wide pelvis and medium height and a low to medium level of fatness. – Local and dairy breeds, comprising Jersey, Casina, Highland, Holstein and Danish Red, the latter two breeds were tall animals, while the former three breeds were small in size. In general the group was poorly muscled and tended to have a high or medium level of fat. – Intermediate group, Avileña, Marchigiana and Simmental: these breeds were characterized by an intermediate muscle conformation and fatness level and were relatively tall. This study provides a detailed assessment or a wide range of variables in the major breeds, and several minor breeds, that are used in breeding programmes across Europe and elsewhere, and will provide information that will be of use to define breeding strategies to meet the demands of the European beef market.

Evaluation of Alternative Methods to Develop Prediction Equations to Predict Carcass Fat-Free Lean Mass

Carcass measurements of 203 pigs representing 7 genetic populations and 4 target weights (100, 114, 128, and 152 kg) were used to evaluate alternative equations to predict carcass fat tissue-free lean mass. Independent variables in the equations included carcass weight and measures of backfat depth and longissimus area. Alternative sets of equations were calculated to evaluate the inclusion of a random effect of week of processing and of the quadratic and cross-product independent variables. In addition, equations were developed from data including the overall data set as well as from the 3 lightest and 3 heaviest target weights. Overall, the addition of the random effect of week did not change the residual standard deviations of the prediction equations. For 4 equations, the inclusion of the random effect of week reduced the absolute value of the regression coefficients. The best equations developed from either the light or heavy pig data sets had less total residual sums of squares and less residual sums of squares accounted for by target BW group than did the best equations developed from the overall data set. In 2 of the 4 cases, the best linear equation developed from the light or heavy data sets had less residual sums of squares than the best equation based on the overall data set.

Effect of genotype and seasonality on pig carcass and meat characteristics

The effect of the genetics and the slaughter time on pig carcasses and raw ham characteristics has been assessed. With this aim, 1257 pigs from five different crosses including Duroc (DU), Landrace (LR) and Large White (LW) in five slaughters distributed along a year (namely, December 2000, March, April, July and November 2001) were used for the study. The variables studied included carcass weight (CW), ham weight (HW), lean meat percentage in the ham (% Lean), pH at 45 min post-mortem (pH 45 min) and at 48 h post-mortem (pH 48 h). The percent of ham yield (% HW–CW ratio) was calculated as the ratio ham weight/carcass weight multiplied by 100. Semimembranosus muscle (SM) from 237 hams was collected at 48 h post-mortem in order to determine the moisture, protein and intramuscular fat content and pH measurement in the laboratory (pH Lab). A univariate analysis of variance including genetics as fixed factor and slaughter time as random factor revealed that carcass and meat traits are influenced by both the time of year in which the animals are slaughtered and the genetics; however, the latter exerts a less significant effect than the slaughter time.

Genetic and phenotypic characterisation of animal, carcass, and meat quality traits from temperate and tropically adapted beef breeds. 2. Abattoir carcass traits

A total of 11 abattoir carcass measures were recorded on 7854 carcasses in temperate (TEMP) and tropically adapted (TROP) beef breeds. Breeds for TEMP included Angus, Hereford, Murray Grey, and Shorthorn; Brahman, Belmont Red, and Santa Gertrudis accounted for TROP breeds. Measurements included carcass weight (CWT), retail beef yield percentage (RBY), intramuscular fat percentage (IMF), subcutaneous fat depth at the P8 site (P8) and at 12/13th rib (RIB), eye muscle length by width (ELW), deep butt temperature (DBTEMP), fat colour score (FATC), meat colour score (MEATC), marbling score (MARB), and carcass muscle score (MUSC). Animals were finished to 3 different market weight endpoints, either on pasture or in a feedlot, and in different geographic regions for the TROP breeds. Both the phenotypic and genetic expressions of the traits were estimated at each level of market weight endpoint and finishing regime. Heritabilities (h2), and genetic (rg) and phenotypic (rp) correlations between traits were estimated for TEMP and TROP separately. The design effects of market weight endpoint and finishing regimes were the most important sources of variation for continuously measured traits. Main effects for the scored traits were finishing regime for FATC and MEATC and market weight endpoint for MARB and MUSC. Feedlot finished cattle had the whitest FATC and the lightest MEATC. For TEMP, estimates of h2 for CWT, RBY, IMF, P8, RIB, ELW, DBTEMP, FATC, MEATC, MARB, and MUSC were 0.39, 0.57, 0.38, 0.36, 0.27, 0.30, 0.10, 0.05, 0.11, 0.17, and 0.14, respectively. In comparison, h2 for the same order of traits for TROP were 0.36, 0.50, 0.39, 0.30, 0.41, 0.32, 0.04, 0.09, 0.11, 0.25, and 0.11. The direction and magnitude of rg between traits were similar for TEMP and TROP, particularly between CWT, RBY, IMF, P8, and RIB. Genetic correlations of RBY were moderate and negative with all measures of fatness, including IMF (–0.38 TEMP and –0.43 TROP). Positive rg existed between all measures of fatness, with MARB and IMF close to unity. Negative rg was estimated between CWT and all fat measurements. Also negative were the rg and rp estimates between CWT and MEATC. For all traits in both TEMP and TROP, domestic weight carcasses exhibited lower additive variance than export market carcasses. However, genetic correlations between traits across market weight endpoints were positive and close to unity, with the exception of RBY for TROP. For TEMP breeds, genetic correlations between finishing regimes were close to unity. However, possible genotype by environment interactions were found for TROP for P8, MEATC, and MARB between finishing in different geographic regions, and between feedlot and pasture finished animals for RBY and MEATC. Genetic improvement of carcass traits is a possibility given the moderate heritabilities, moderate to strong genetic correlations, and little evidence of genotype by environment interactions.

Genetic relationships of body condition score with carcass traits in Limousin cattle (2003)

Field data from the North American Limousin Federation was used to determine the heritability and genetic correlations of body condition score (BCS) with carcass traits. Carcass traits included carcass weight, ribeye area, fat thickness, intramuscular fat, and % kidney, pelvic, and heart fat, and all were estimated to be lowly to moderately heritable (0.14 to 0.34). Heritability of BCS was 0.19. Favorable correlations existed between ribeye area and carcass weight (0.50), ribeye area and BCS (0.60), and carcass weight and BCS (0.28). Unfavorable correlations existed among ribeye area and intramuscular fat (-0.40), carcass weight and intramuscular fat (-0.23), and intramuscular fat and BCS (-0.64). These results suggest that selection for BCS should be effective and would result in some favorable changes in ribeye area and carcass weight but with unfavorable change in marbling.

Relationships of Concentrations of Endocrine Factors at Antemortem and Postmortem Periods to Carcass Weight and Backfat Thickness in Pigs

Carcass weight and backfat thickness are two of important elements in determining the carcass trait in pigs and are studied on animal genetics, nutrition, and endocrinology. Growth factors stimulate or inhibit the proliferation and differentiation of various cells. In particular, insulin-like growth factors (IGFs), transforming growth factor (TGF)-β, and epidermal growth factor (EGF) are involved in the growth and maintenance of muscle. Also, dehydroepiandrosterone-sulfate (DHEA-S) and cortisol are known to be related to the obesity and subcutaneous fat depth in pigs. Therefore, this study was performed to relate growth factors (IGFs, TGF-β1, and EGF) and hormones (cortisol and DHEA-S) concentrations at antemortem and postmortem periods to carcass traits including carcass weight and backfat thickness. Blood and m. Longissimus were collected in pigs at antemortem (30 days before slaughter) and postmortem periods. After slaughtered, carcass weight and backfat thickness were measured. Growth factors and hormones in serum and m. Longissimus were measured by radioimmunoassay or enzyme-linked imuunosorbent assay. Before antemortem period, serum IGF-I and -II concentrations were positively correlated with the carcass weight and backfat thickness in gilts, and the concentrations of TGF-β1 and cortisol in barrows show the correlation with only carcass weight. Also, the positive correlations of muscular IGFs and TGF-β1 at postmortem 45 min with the carcass weight and backfat thickness were detected. Consequently, these results suggest that the serum and muscular endocrine factors are involved in the carcass weight and backfat thickness in pigs.