Characterization of biological types of cattle (Cycle IV): carcass traits and longissimus palatability

Potential of in-plant intramuscular fat predictions to enable sheep breeders to incorporate consumer preferences in breeding programmes

The inclusion of eating quality traits in sheep genetic improvement programmes is desirable. Intramuscular fat (IMF) plays a key role in ensuring consumer satisfaction when eating lamb, but genetic progress for IMF is constrained by a lack of routine data collection. This study investigated the potential for IMF predictor traits to substitute for measured IMF in genetic improvement programmes. Carcass and predicted IMF (near-infrared estimated IMF and marbling score) data were available on 10,113 New Zealand lambs, 1678 of which also had measured chemical IMF on a slice of M. longissimus lumborum on which the predictions of IMF had been made. Genetic antagonisms were observed between carcass lean traits and IMF. The genetic correlation between the predictors and measured IMF approached one, indicating that predictors of IMF can be used in genetic improvement programmes. Through using selection indexes, simultaneous increases in IMF and the existing terminal selection index are possible, provided all traits are measured. This study highlights the importance and potential of predicted IMF to achieve genetic improvement in traits of importance to consumers.

Invited review: A carcass and meat perspective of crossbred beef × dairy cattle

Crossbreeding dairy cows with beef sires has greatly altered the consist of U.S. dairy-influenced slaughter cattle and generated an influx of crossbred beef × dairy cattle to the U.S. fed beef slaughter supply in 2021. This review provides a summary of our observations of carcass and meat traits in the recent U.S. beef × dairy crossbred population and, based on these observations, exposes future opportunities for consideration. Strip loin steaks from beef × dairy cattle can be marketed alongside conventional beef products in retail display without consumer discrimination based on color or steak shape previously experienced in steaks from straightbred dairy cattle. Additionally, beef from crossbred beef × dairy cattle cannot be discriminated against for eating quality attributes (tenderness, flavor, and juiciness) as it exhibits similar, if not improved, performance of these attributes to beef from conventional beef cattle. We have also demonstrated that live expression of beef-type versus dairy-type character within the beef × dairy crossbred population has minimal effect on eating quality. With proper genetic selection and management, crossbred beef × dairy cattle can capture carcass premiums from an optimal combination of carcass quality (marbling) and red meat yield. Future beef × dairy crossbred mating and management systems should emphasize increases in total carcass muscling and reductions in liver abscess prevalence. A story of quality, sustainability, and traceability in the large and constant supply of beef from crossbred beef × dairy cattle may present profitable branding and marketing opportunities for these products.

Meat tenderness: advances in biology, biochemistry, molecular mechanisms and new technologies

Meat tenderness is an important quality trait critical to consumer acceptance, and determines satisfaction, repeat purchase and willingness-to-pay premium prices. Recent advances in tenderness research from a variety of perspectives are presented. Our understanding of molecular factors influencing tenderization are discussed in relation to glycolysis, calcium release, protease activation, apoptosis and heat shock proteins, the use of proteomic analysis for monitoring changes, proteomic biomarkers and oxidative/nitrosative stress. Each of these structural, metabolic and molecular determinants of meat tenderness are then discussed in greater detail in relation to animal variation, postmortem influences, and changes during cooking, with a focus on recent advances. Innovations in postmortem technologies and enzymes for meat tenderization are discussed including their potential commercial application. Continued success of the meat industry relies on ongoing advances in our understanding, and in industry innovation. The recent advances in fundamental and applied research on meat tenderness in relation to the various sectors of the supply chain will enable such innovation.

Genetic Analysis of Major Carcass Traits of Korean Hanwoo Males Raised for Thirty Months

Simple Summary

Generally, Korean Hanwoo males produced under a 24-month production cycle (PROD24) are evaluated as a part of the progeny test program. However, there is little information on other males outside the PROD24, such as those raised under a 30-month production cycle (PROD30) for higher profits. Therefore, we investigated PROD30 males for important carcass traits (carcass weight, eye muscle area, backfat thickness, and marbling score) using a reasonably large dataset to understand their genetic merit. To do so, we estimated the genetic parameters of traits using animal model. Our analysis revealed moderate to high heritability values for the studied traits. The marbling score was found to be highly heritable at 0.56. The genetic correlation between traits was mostly moderate to low, and the backfat thickness was poorly correlated with the marbling score. These results are consistent with many previous reports on PROD24. Our study suggests that PROD30 and PROD24 males might have somewhat similar genetic potential, as well as similar genetic backgrounds. Thus, it could be concluded that there is further scope for PROD30 males to improve Hanwoo males’ overall prediction accuracy, especially under a genomic selection program, together with PROD24 males.

Abstract

Understanding animals’ genetic potential for carcass traits is the key to genetic improvements in any beef cattle. In this study, we investigated the genetic merits of carcass traits using Hanwoo males raised in a 30-month production system (PROD30). We achieved this using a dataset comprising 6092 Hanwoo males born between 2005 and 2017 and measures of four carcass traits (carcass weight, CWT; eye muscle area, EMA; backfat thickness, BFT; and marbling score, MS). Genetic parameters were estimated using a multiple-trait animal model through the AIREMLF90 program. According to the multiple-trait model, the h² of CWT, EMA, BFT, and MS were 0.35 ± 0.04, 0.43 ± 0.05, 0.48 ± 0.05, and 0.56 ± 0.05, respectively. The strongest genetic correlation (r_g) was obtained between CWT and EMA (0.49 ± 0.07), whereas it was negligible between CWT and BFT. EMA and MS were also moderately correlated, whereas there was a relatively low negative correlation between EMA and BFT (−0.26 ± 0.08). Our study revealed a consistent indirect genetic improvement in animals from 2005 onwards. Although Hanwoo improvement has mainly focused on males under a 24-month production cycle, we observed PROD30 males to have somewhat similar genetic potential. Our results provide useful insights into the genetic merits of PROD30 males for the first time, which may facilitate future studies on them and their integration into the Hanwoo National Evaluation for genomic selection.

Effects of additives in wet brewery residue silage on lamb carcass traits and meat quality

The objective was to evaluate the use of wet brewery residue (WBR) silage additives on carcass characteristics and sheep meat quality. Thirty-two Santa Inês male sheep uncastrated with initial body weight of 22.61 ± 7.2 kg were allocated to a completely randomized design with four treatments: (1) WBR silage without additive (WBRS), (2) WBR silage with milled corn (WBRS + MC), (3) WBR silage with wheat bran (WBRS + WB), and (4) WBR silage with cassava flour (WBRS + CF) and eight replicates. WBRS + WB resulted in lower cold carcass weight than WBRS + CF; however, this reduction was not sufficient to alter the carcass commercial yield or loin-eye area. The leg cut of animals fed WBRS + WB showed less value than those animals fed with WBRS + CS. The meat lightness of WBRS was higher that of WBRS + MC, WBRS + WB, and WBRS + CF. The cooking loss for WBRS + WB was less than those animals fed with WBRS + CS. However, meat protein, meat cholesterol, and shear force were similar among treatments (17.69%, 42.46 mg/100 g of meat, and 2.48 kgf/cm², respectively). The use of additives in wet brewery residue silage does not improve carcass characteristics or the quality of sheep meat, and it is therefore recommended to use WBR silage without additives.

Perception of consultants, feedlot owners, and packers regarding the optimal economic slaughter endpoint in feedlots: a national survey in Brazil (Part I)

Little information exists regarding the optimal economic slaughter endpoint (OSE) for feedlot-finished cattle in Brazil. This study investigated the perceptions of Brazilian feeders regarding the optimal time for slaughter. A total of 52 interviews were conducted involving nutritionist-consultants (n = 23), feedlot owners (n = 21), and packer-owned feedlots (n = 8). The results showed that 65% of the interviewees used weight and fat cover, both estimated visually, to determine the moment for slaughter. Identifying the ideal time for slaughter was considered a challenge for respondents, and 85% of them recognized that their current slaughter endpoint identification method needed improvements. Regarding decision support systems, 58% of respondents reported they would purchase a computer program to help identify OSE, and 73% would be interested in incorporating a prototype of such a system into their feedlots. Carcass dressing (38%) and price (25%) were the main factors driving the feeder’s choice of meatpacker, followed by carcass premiums (10%). Meat quality was found to be an irrelevant criterion for Brazilian meatpackers in awarding both premiums (5%) and deductions (3%). Slaughter endpoint is determined subjectively by the Brazilian feeders, based on a visual evaluation of both weight and fatness.

Resistance to pH decline and slower calpain-1 autolysis are associated with higher energy availability early postmortem in Bos taurus indicus cattle

Beef from Bos taurus indicus is associated with toughness compared to Bos taurus taurus, suggesting there is antagonism between adaptability to heat and beef quality. Resistance to cellular stress in muscle may be protective postmortem, thereby delaying its conversion to meat. Therefore, our objective was to determine pH decline, calpain-1 and caspase 3 activation, and proteolysis in different biological cattle types. Angus, Brangus, and Brahman steers (n = 18) were harvested, and Longissimus lumborum were assessed postmortem for pH decline, ATP content, protease activation, and calpastatin content; and myofibrillar protein degradation was evaluated in beef aged to 14d. Brahman Longissimus lumborum exhibited resistance to pH decline, greater ATP content at 1 h, and delayed calpain-1 autolysis. Although content of caspase-3 zymogen was lower in Brahman, there was no evidence of caspase-3 mediated proteolysis. Greater resistance to energetic and pH changes early postmortem in Brahman Longissimus lumborum are associated with calpain-1 autolysis but not mitochondria mediated apoptosis.

Dressing percentage and the differential between live weight and carcass weight in cattle are influenced by both genetic and non-genetic factors1

The objective of the present study was to quantify the genetic and non-genetic contributors to variability in both carcass dressing percentage and dressing difference (i.e., the difference between carcass weight and live weight immediately prior to slaughter) in young animals and cows. The datasets contained 18,479 young animals from 653 herds, and 2,887 cows from 665 herds. Live weight records within 7 d of slaughter and associated carcass weight were available for all animals. Association analyses were undertaken using linear mixed models with fixed effects for the model of young animals consisting of animal breed, days between the date of last recorded live weight and slaughter date, heterosis and recombination loss coefficients, dam parity, a 3-way interaction between whether the animal originated in a dairy or beef herd, animal sex, and age at slaughter, as well as a 2-way interaction between calendar year of slaughter and month of slaughter; contemporary group was included as a random effect. Fixed effects in the cow model were cow breed, the number of days between the date of last recorded live weight and slaughter date, heterosis and recombination loss coefficients, the number of days postcalving, parity of the cow, and a 2-way interaction between calendar year of slaughter and month of slaughter; contemporary group was included as a random effect. The mean dressing percentage (phenotypic standard deviation in parentheses) and dressing difference in young animals were 55.86% (3.21%) and 280.03 kg (41.44 kg), respectively. Steers had the heaviest dressing difference at 34.18 and 60.44 kg heavier than a 16-mo old bull and 22-mo old heifer, respectively. Dressing difference for 30-mo old Simmental steers (breed with heaviest dressing difference) was 41.66 kg heavier than 30-mo old Belgian Blue steers (breed with lightest dressing difference). The heritability of dressing percentage (0.48) and dressing difference (0.35) in young animals was relatively similar to each other, in contrast to dressing percentage (0.08) in cows which was considerably lower than dressing difference (0.28). Considerable genetic variability existed in dressing difference amongst young animals (genetic standard deviation of 15.03 kg), despite the near unity genetic correlation (0.93) between carcass weight and live weight. This therefore indicates that genetic selection for increased saleable product can be achieved by selecting for increased carcass weight while concurrently selecting for lighter animals although the opportunity is limited by the strong part-whole relationships that exists between carcass weight, live weight, and dressing difference.

Characterisation of beef production systems and their effects on carcass and meat quality traits of Piemontese young bulls

Using the Piemontese breed as a case study, we characterised beef production systems within the EU classification, and investigated their effects on carcass and meat quality traits. The research involved 1,327 young bulls fattened on 115 farms. The production systems identified by hierarchical cluster analysis were: traditional (restricted feeding and either tie-stalls or loose-housing), modern breeders and fatteners and specialised fatteners (the last two were divided in those using or not using total mixed rations). Despite the large variability in management techniques within production systems, production systems affected (P < 0.05) farm size, animal density, environmental scoring, diet, slaughter age and all carcass traits except weight. Lightness (L*) of Longissimus thoracis was the only meat quality trait affected (P < 0.05), with values greater in the traditional tie-stall system (+0.9 L*). Given the very limited effect of production systems on meat quality traits, factors related to individual animals within farms, such as genetics, should be considered for their improvement.

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.

Genomewide association mapping and pathway analysis of meat tenderness in Polled Nellore cattle

Brazil is one of the world's largest beef exporters, although the product has a low price due to quality issues. The meat exported by Brazil is considered medium and low quality by international buyers, mainly due to lack of tenderness. The predominant Zebu breeds (80% Nellore) are known for producing tougher beef than taurine breeds. Nonetheless, some studies have shown that there is substantial genetic variability for tenderness within the Nellore breed, although it is a difficult trait to improve by conventional selection methods. Therefore, the aim of this study was to perform a genomewide association study (GWAS) and a gene set enrichment analysis to identify genomic regions and biologically relevant pathways associated with meat tenderness in Polled Nellore cattle. Data consisted of Warner-Bratzler shear force values of LM from 427 Polled Nellore animals divided into 3 experimental slaughters (years 2005, 2008, and 2010). The animals were genotyped with either the Illumina BovineHD BeadChip (777k, on 61 samples) or the GGP Indicus HD chip (77k, on 366 samples). Single nucleotide polymorphisms were excluded when the call rate was <90%, the Hardy-Weinberg proportions -value was <1% (Fisher exact test, Bonferroni adjusted), and the minor allele frequency was <1%. Imputation from the GGP Indicus HD chip to the Illumina BovineHD BeadChip was performed using the FImput program. Genomewide association analysis was performed using the Efficient Mixed Model Association eXpedited (EMMAx) and the population parameters previously determined (P3D) methods. The GWAS was complemented with a gene set enrichment analysis performed using the FatiGO procedure. Significant markers ( < 0.0001) explaining a larger proportion of variation than other significant SNPs were located on chromosomes 3, 13, 17, 20, 21, and 25, indicating QTL associated with meat tenderness throughout the genome. Additionally, gene set analysis identified 22 Gene Ontology functional terms and 2 InterPro entries that showed significant enrichment of genes associated with tenderness. The functional categories included protein tyrosine and serine/threonine kinase activity, calcium ion binding, lipid metabolic process, and growth factors, among others. These results help to elucidate the genetic architecture and metabolic pathways underlying this trait, which is of extreme economic and social importance to Brazil, because Nellore is the dominant beef cattle breed in the country.

Crossbred young bulls and heifers sired by double-muscled Piemontese or Belgian Blue bulls exhibit different effects of sexual dimorphism on fattening performance and muscularity but not on meat quality traits

As double-muscled Belgian Blue (BB) and Piemontese (PIEM) breeds are heavily selected for different objectives (the former mainly for muscularity, the latter for ease of calving), the aim of this study was to compare sexual dimorphism in 56 crossbred young bulls and heifers obtained from dairy cows mated to bulls of the two beef breeds. Young PIEM- and BB-sired bulls had similar fattening performances and beef traits, although the BB crossbreds were slightly more muscular. Otherwise, the BB-sired heifers exceeded the PIEM-sired heifers in growth rate (1.12 vs. 0.98kg/d), feed efficiency (0.129 vs. 0.121kg/kg DM), increases in muscle scores (1.45 vs. 0.98 SEUROP scores) and carcass yield (0.612 vs. 0.605), but not in fatness, retail cut proportions and meat quality traits. Sexual dimorphism is, therefore, less distinct in BB than in PIEM crossbreds. In conclusion, BB sires are to be preferred for "product quality", and PIEM sires for "process quality", on account of welfare and ethical issues.

Accuracy of genomic breeding values for meat tenderness in Polled Nellore cattle

Zebu () cattle, mostly of the Nellore breed, comprise more than 80% of the beef cattle in Brazil, given their tolerance of the tropical climate and high resistance to ectoparasites. Despite their advantages for production in tropical environments, zebu cattle tend to produce tougher meat than Bos taurus breeds. Traditional genetic selection to improve meat tenderness is constrained by the difficulty and cost of phenotypic evaluation for meat quality. Therefore, genomic selection may be the best strategy to improve meat quality traits. This study was performed to compare the accuracies of different Bayesian regression models in predicting molecular breeding values for meat tenderness in Polled Nellore cattle. The data set was composed of Warner-Bratzler shear force (WBSF) of longissimus muscle from 205, 141, and 81 animals slaughtered in 2005, 2010, and 2012, respectively, which were selected and mated so as to create extreme segregation for WBSF. The animals were genotyped with either the Illumina BovineHD (HD; 777,000 from 90 samples) chip or the GeneSeek Genomic Profiler (GGP Indicus HD; 77,000 from 337 samples). The quality controls of SNP were Hard-Weinberg Proportion -value ≥ 0.1%, minor allele frequency > 1%, and call rate > 90%. The FImpute program was used for imputation from the GGP Indicus HD chip to the HD chip. The effect of each SNP was estimated using ridge regression, least absolute shrinkage and selection operator (LASSO), Bayes A, Bayes B, and Bayes Cπ methods. Different numbers of SNP were used, with 1, 2, 3, 4, 5, 7, 10, 20, 40, 60, 80, or 100% of the markers preselected based on their significance test (-value from genomewide association studies [GWAS]) or randomly sampled. The prediction accuracy was assessed by the correlation between genomic breeding value and the observed WBSF phenotype, using a leave-one-out cross-validation methodology. The prediction accuracies using all markers were all very similar for all models, ranging from 0.22 (Bayes Cπ) to 0.25 (Bayes B). When preselecting SNP based on GWAS results, the highest correlation (0.27) between WBSF and the genomic breeding value was achieved using the Bayesian LASSO model with 15,030 (3%) markers. Although this study used relatively few animals, the design of the segregating population ensured wide genetic variability for meat tenderness, which was important to achieve acceptable accuracy of genomic prediction. Although all models showed similar levels of prediction accuracy, some small advantages were observed with the Bayes B approach when higher numbers of markers were preselected based on their -values resulting from a GWAS analysis.

Meat quality traits as a function of cow maturity

To investigate the physico-chemical and sensory properties of striploin muscles, 90 Hanwoo carcasses (QG 1⁺ ) were randomly selected within six maturity levels (4 to 9 according to age in months). Results demonstrated that the protein contents at maturity levels 4 and 5 were significantly higher than 9. No significant difference in fat, moisture and collagen contents were found at different maturity levels (P > 0.05). The quantity of collagen type I and ratio of type I to III were observed at higher maturity levels; collagen type III showed significantly high levels (P > 0.05) at low maturity and decreased with increase in maturity levels. Warner-Bratzler shear force (WBSF) was significantly lower in groups 4 to 6, whereas water holding capacity (WHC) was significantly higher than maturity level 8 and 9 groups (P < 0.05). There were no significant differences in cooking loss among the maturity level groups (P > 0.05). Color properties, L* values of striploin muscle from maturity level 4 were significantly different from level 9 (P < 0.05). Sensory evaluation at level 4-6 groups had significantly higher tenderness and overall likeness scores than level 9 (P < 0.05). The maturity levels were significantly correlated with age, fat, protein content, WHC, WBSF, cooking loss, CIE L* values and sensory properties like tenderness, juiciness, flavor-likeness and overall likeness.

The Relationship between Chemical Compositions, Meat Quality, and Palatability of the 10 Primal Cuts from Hanwoo Steer

The relationship between chemical compositions, meat quality traits, and palatability attributes in 10 primal cuts from Hanwoo steer carcasses were assessed. Sensory palatability attributes of Hanwoo beef were more closely related with fat content than to moisture or protein content. Among the chemical compositions, only fat had a significant correlation with juiciness (0.67, p<0.001), tenderness (0.32, p<0.05), and overall palatability (0.56, p<0.001). Oleic acid (%) was not significantly related with overall palatability (p>0.05). Overall palatability was negatively correlated with drip loss (−0.32, p<0.05), cooking loss (−0.36, p<0.05), and shear force (−0.54, p<0.01). The correlation between fat content and overall palatability was increased when higher fat cuts (Ansim, Dungsim, Chaekeut, Yangjee, and Kalbi) were analyzed, compared to lower fat cuts (Moksim, Abdari, Udun, Suldo, and Satae). Also, the correlation between shear force and overall palatability was decreased in lower fat cuts compared to higher fat cuts. Our results suggest that the palatability of Hanwoo beef can be improved by increasing fat content in muscles, as increased fat content leads to an increase in sensory tenderness, flavor, and juiciness.

Genetic parameters for yearling weight, carcass traits, and primal-cut yields of Hanwoo cattle

Genetic parameters associated with yearling weight, carcass traits, and primal-cut yields of male Hanwoo cattle were investigated using univariate and bivariate animal models. The mean yearling weight (YWT), carcass weight (CWT), longissimus muscle area (LMA), backfat thickness (BFT), and marbling score (MS) were 352.47 ± 0.40 kg, 337.39 ± 0.64 kg, 78.28 ± 0.13 cm2, 8.45 ± 0.05 mm, and 3.25 ± 0.03, respectively. Total primal-cut yield (TPC) was 78.95 ± 0.10% of CWT, of which 42.3% was contributed by the forequarters (chuck, CHK; shoulder, SLD; ribs, RIB; and brisket and flank, BAF). Loins, top round (TRND), and round (RND) were associated with yields of 13.57%, 5.45 ± 0.01%, and 8.87 ± 0.02%, respectively. The largest cut studied was ribs (15.67 ± 0.03%). The estimated heritabilities (h2) of YWT, CWT, LMA, BFT, and MS were 0.18 ± 0.02, 0.29 ± 0.04, 0.38 ± 0.05, 0.45 ± 0.05, and 0.62 ± 0.07, respectively. Shoulder yield was highly heritable in Hanwoo steers (0.83 ± 0.13), followed by the yields of round (0.66 ± 0.12), striploin (0.64 ± 0.12), top round (0.62 ± 0.12), sirloin (0.60 ± 0.12), and total primal-cut yield (0.52 ± 0.11). The h2 values of CHK, BAF, RIB, and tenderloin (TLN) ranged from 0.19 ± 0.09 to 0.41 ± 0.11. Generally, the genetic CV was low for most traits (2.33%-6.15%), except for CHK, BFT, and MS. The genetic correlation (rg) was strong between YWT and CWT (0.77 ± 0.06). The greatest positive and negative rg among carcass traits were those between LMA and CWT (0.52 ± 0.08) and between LMA and BFT (-0.30 ± 0.09), respectively. The correlation between CHK and SLD (0.81 ± 0.14), and those between SLD, TLN, TRND, and RND, were mostly strong (0.77-0.87), but the rg between RIB and other traits were strongly negative. The TPC yield showed moderate to high rg with most primal cuts. The YWT, CWT, and LMA correlated notably with CHK, SLD, and loin yields, especially LMA. However, BFT and MS were negatively correlated with many primal cuts but RIB. Those rg estimates were also opposite of that of LMA and CWT with primal cuts. Phenotypic correlations (rp) were generally weaker than rg estimates. The rp of YWT, CWT, and LMA were either zero or moderately negative compared to those of the BFT and MS with primal cuts. Most primal cuts yielded positive rp estimates among them, except for RIB. Our results suggest that direct selection for YWT, various carcass traits, and primal-cut yields may increase the carcass value of Hanwoo males.

Effect of Quality Grade and Storage Time on the Palatability, Physicochemical and Microbial Quality of Hanwoo Striploin Beef

The effects of quality grade and storage time on physicochemical, sensory properties and microbial population of Hanwoo striploin beef were investigated. After a total of 30 Hanwoo beef were slaughtered, the cold carcasses were graded by official meat grader at 24 h postmortem. The carcasses were categorized into five groups (quality grade 1++, 1+, 1, 2, and 3) and were vacuum-packaged and stored. The samples were kept for 1, 4, 6, 8, 11, 13, 15, 18, 20, 22 and 25 d for analyses. As the quality grade was increased, moisture, protein and ash contents decreased (p<0.05). Higher quality grade corresponded with higher fat contents. The shear force values decreased with increasing quality grade and showed decreases sharply during the first 4 d (p<0.05). pH, water holding capacity, cooking loss, and volatile basic nitrogen for grade 1++ groups were lower than for grade 3 (p<0.05). CIE L* and b* values increased as increased quality grade (p<0.05). Meat color decreased until 13 d and fluctuated after 15 d of storage (p<0.05). Regarding the sensory scores, higher quality grade corresponded with higher juiciness, tenderness, flavor, fatty and palatability scores (p<0.05). Generally, increased storage time for 15 d improved sensory scores attributes. Results indicate that a high quality grade could positively influence physicochemical and sensory properties.

Growth, carcass traits and palatability: can the influence of the feeding regimes explain the variability found on those attributes in different Uruguayan genotypes?

It is well known what genetic and nutritional factors affect growth and meat quality, but there is less information related to interactive importance of them during the productive process. These systems are mainly based on rangelands affecting animal growth in early stages of life thus producing smaller cattle and reduced retail yield comparing with well grown calves. During the last ten years, Uruguayan livestock production systems have been intensified using improved pastures, concentrates and better genetic. The main breeds in Uruguay are Hereford, Angus and their crosses. These British breeds are under genetic evaluation programs which consider carcass trait parameters. It is important for beef industry to know if interactions between genotype and nutrition during growth and fattening phases are influencing production, efficiency, carcass weight and meat quality attributes. The aim of this article is to present information obtained under different feeding strategies during the post weaning and fattening and their influence on those attributes.

Comparison of Physicochemical and Functional Traits of Hanwoo Steer Beef by the Quality Grade

The physicochemical and functional traits for loin muscles of Hanwoo steers were compared by quality grade (QG). A total of 500 Hanwoo steers were slaughtered, their carcasses were categorized into four groups (QG 1++, 1+, 1, and 2), and the longissimus dorsi muscles were analyzed. QG 1++ group had the highest fat and lowest moisture content (p<0.05). QG 1++ showed higher L* and b* color values, higher cooking loss, and lower shear force values, compared with the other groups (p<0.05). The flavor, tenderness, juiciness, and preference scores by sensory evaluation were highly ranked for premium QG groups (1++ and 1+). Regarding the micro compounds, QG 1 and QG 2 had greater amounts of inosine monophosphate, and QG 2 had greater amounts of anserine, carnosine, and creatine, than QG 1++ (p<0.05). QG 1++ and 1+ had higher percentages of oleic acid (C18:1) than QG 2 (p<0.05). Within premium QG 1++ and 1+, the results of the nucleotides, free amino acids, dipeptides, and fatty acids did not show any distinctive differences. Hanwoo beef as determined by the current grading system was not significantly different in terms of functional components; the only significant difference was in intramuscular fat content.

Effect of muscle type and vacuum chiller aging period on the chemical compositions, meat quality, sensory attributes and volatile compounds of Korean native cattle beef

The present study demonstrates the effects of different muscle types and chiller ageing periods on the chemical composition, meat quality parameters, sensory characteristics and volatile compounds of Karean native cattle beed. Longissimus dorsi (LD) and Semitendinosus (ST) muscles aged for 7 days and 28 days were used. Moisture, cooking loss, total collagen and Warner-Bratzler shear force (WBSF) values for the ST were higher than the LD muscle regardless of ageing period (P < 0.05). The LD muscle had higher intramuscular fat (IMF) (P < 0.05). Ageing for 28 days decreased WBSF values whereas it increased thiobarbituric acid of both muscles. Moreover, tenderness, juiciness and flavor scores were significantly higher for the LD muscle at both ageing periods. Increased ageing time improved tenderness of both muscles, and increased juiciness of the LD muscle, whereas there was decreased flavor score of ST muscle (P < 0.05). The majority of the volatile compounds formed from the oxidation of lipids showed differences between the two muscles. Ageing for 28 days increased in the amounts of many volatile compounds; however, the amounts of some important volatile compounds were decreased. These results clearly demonstrate that muscle type and ageing have a potential effect on meat quality, sensory characteristics and volatile profile.

Relationships between muscle characteristics and meat quality traits of young Charolais bulls

Charolais bull calves (106) were used to study the variability in meat quality attributes in relation to the variability in muscle characteristics in the Longissimus thoracis (LT) muscle. The variability in traits was adjusted either to constant age or constant weight at slaughter and thus originated only from differences between animals born, reared and fattened in the same location. The following meat quality attributes were measured: the strength of the myofibrillar resistance to a 20% compression strain measured on the raw meat 2, 7 and 21 days post mortem; and taste panel scores of tenderness (initial and overall), flavour and juiciness of steaks grilled to a 55°C core temperature 6 or 15 days post-mortem. The following muscle characteristics were measured 24 h after slaughter: pH, dry matter, protein, lipid, heme iron and collagen contents, collagen solubility, LDH and ICDH activity, the proportion of slow twitch myosin heavy chain, the mean muscle fibre area and the mean sarcomere length. One fourth to one third of the variability of 2 day mechanical strength and 15 day tenderness or flavour scores were related to the variability in muscle characteristics. Tenderness and strength measurements were predominantly related to the muscle fibre area, collagen characteristics and energetic metabolic activity. Dry matter content was the principal muscle characteristic related to flavour.

Effects of quality grade on the chemical, physical and sensory characteristics of Hanwoo (Korean native cattle) beef

The effects of quality grade (which reflects relative marbling) on the chemical, physical and sensory properties was investigated using Korean native cattle (Hanwoo) beef. Thirty-six Hanwoo cows were slaughtered and the carcasses were graded at 24h postmortem according to the Korean carcass grading system. The quality grade 1 (high quality), grade 2 and grade 3 (low quality) were based on the marbling score of longissimus dorsi (LD) muscles. The effects of quality grade on the meat quality parameters of beef LD muscle were assessed during aging. Loin-eye area, fat thickness and yield grade were all similar for the three quality groups. Mean lean color, fat color and maturity scores did not differ among quality grade groups (P>0.05). pH, Sarcomere length, WHC, collagen content, cooking loss, shear force and MFI were not affected by quality grade groups. Drip loss for grade 1 group was significantly lower than that for grade 3 groups (P<0.05). At initial tenderness evaluation of steaks, no differences among the three grades were observed; however, with additional days of storage, grade 1 steaks had higher tenderness score than grade 3 steaks (P<0.05). Increased postmortem aging time improved tenderness attributes regardless of quality groups. No significant differences were found among the quality grade groups for flavor (P>0.05). The grade 1 group had the highest juiciness score, and grade 3 groups had the lowest score (P<0.05), but postmortem aging did not influence flavor and juiciness. The quality grades were more strongly related to juiciness than tenderness or flavor.

Growth and carcass characteristics of pasture fed LHRH immunocastrated, castrated and intact Bos indicus bulls

The effectiveness of a luteinizing hormone-releasing hormone (LHRH) fusion protein vaccine or surgical castration, at two years of age, on growth and carcass characteristics of Bos indicus bulls was evaluated. Seventy Nelore-cross bulls were divided into three groups: (1) immunized, (2) castrated and (3) intact control. At slaughter (three years of age), intact bulls had higher body weights, ADG, carcass weights, and muscle percentage compared to immunized and surgically castrated animals. Both castrated and immunized animals had greater marbling and percent carcass fat than the intact bulls. Average tenderness scores were inferior for intact bulls compared to immunized and castrated animals, but these differences were not significant (P>0.05). Juiciness, flavor, thawing, nor cooking losses differed significantly among the three groups. Immunocastration was effective in producing carcass traits similar to that of surgical castration. Therefore, immunization with LHRH fusion proteins appears to have practical utility in the management and castration of grazing bulls.

Effects of breed of sire on carcass composition and sensory traits of lamb

This experiment was conducted to compare meat quality and carcass composition of a diverse sampling of sheep breeds. Finnsheep, Romanov, Dorper, White Dorper, Katahdin, Rambouillet, Suffolk, Texel, Dorset, and Composite (½ Columbia rams to 1/4; Hampshire × 1/4; Suffolk) rams were mated to mature Composite ewes. Lambs (n = 804) were reared intensively, grain finished, and serially harvested over a 63-d period. Average harvest age was 216 d and average HCW was 30.7 kg. At a common harvest age, progeny of Suffolk sires were heavier than progeny of all other breeds (P < 0.05) and their carcasses were heavier (P < 0.05) than progeny of all other breeds, except White Dorper and Dorper. Progeny of Finnsheep and Romanov sires had lighter (P < 0.05) carcasses than progeny of all other breeds. Progeny of Texel, Suffolk, White Dorper, and Dorper sires had larger (P < 0.05) LM area than all other breeds. Progeny of Finnsheep and Romanov sires had smaller (P < 0.05) LM area than all other breeds. Fat thickness at the 12th rib was greater (P < 0.05) for progeny of Dorper sires than those of all other breeds, except White Dorper and Katahdin. Fat thickness at the 4th sacral vertebrae was greater (P < 0.05) for progeny of White Dorper and Dorper sires than those of all other breeds. On a carcass weight-constant basis, progeny of Suffolk sires had a lesser (P < 0.05) percentage of ether-extractable carcass fat than progeny of all other breeds, except Texel. Regardless of harvest endpoint (age-constant or HCW-constant), LM of progeny of Finnsheep and Romanov sires contained a greater (P < 0.05) percentage of intramuscular fat and received greater (P < 0.05) marbling scores than Rambouillet, Suffolk, Texel, Dorset, or Composite. Regardless of harvest endpoint, progeny of Finnsheep, Romanov, and Katahdin sires had smaller LM slice shear force values and greater trained sensory panel tenderness ratings at 7 d postmortem than did progeny of Composite, Suffolk, and Dorset sires (P < 0.05). At an age-constant basis, small differences (P < 0.05) were observed among breeds for lamb flavor intensity scores; however, when means were adjusted to a carcass weight-constant basis, breed of sire did not affect flavor intensity or off-flavor scores. These results document that each breed has relative strengths and weaknesses across traits, and that no single breed excels for all growth, carcass, and sensory traits.

Assessment of meat quality properties and development of a palatability prediction model for Korean Hanwoo steer beef

Effects of the Korean carcass-grading system on carcass traits and meat quality parameters for the longissimus dorsi (LD) and semimembranosus (SM) muscles were investigated for Hanwoo steer beef. High quality grade beef cuts had significantly higher intramuscular fat content than those of low quality grade beef cuts. To establish a guaranteed system of eating quality for Hanwoo steer beef, a palatability prediction model was developed. The model development approach used canonical discriminant analysis and multivariate regression to assess effects of muscle type, cooking method, and aging treatment on Hanwoo beef quality grade. The palatability prediction model can provide Korean consumers with detailed information about expected eating quality for an individual cut, as well as provide critical information to the industry for maintaining high-quality beef production. The model is a significant advance in grading compared with the traditional carcass grading system, which applies a single quality grade to an entire carcass.

Characterization of biological types of cattle (Cycle VIII): carcass, yield, and longissimus palatability traits

The objective of this experiment was to evaluate alternative sources of tropically adapted cattle germplasm and compare them with Angus- (AN) and Hereford- (HE) sired steers. Carcass, yield, and longissimus thoracis palatability traits from F(1) steers (n = 621) obtained from mating AN and MARC III cows to HE, AN, Brangus (BR), Beefmaster (BM), Bonsmara (BO), or Romosinuano (RO) sires were compared. Data were adjusted to constant age (426 d), carcass weight (340 kg), fat thickness (1.0 cm), fat trim percentage (25%), and marbling (Small(00)) endpoints. For Warner-Bratzler and slice shear force and trained and untrained sensory panel traits, data were obtained on LM from ribeye steaks stored at 2 degrees C for 14 or 15 d postmortem. The following comparisons were from the age-constant endpoint. Carcasses from BM-, AN-, and BR-sired steers (358, 355, and 351 kg, respectively) were heavier (P < 0.05) than carcasses from steers from HE (343 kg) and BO (331 kg) sires; RO-sired steers (318 kg) had the lightest (P < 0.05) carcasses. Adjusted fat thicknesses for AN- and BM-sired steers (1.3 and 1.2 cm, respectively) were greater (P < 0.05) than for steers from BR (1.0 cm) and BO (0.9 cm) sires; RO-sired steers (0.8 cm) had the least fat thickness. Longissimus areas were larger (P < 0.05) for BO- and BR-sired steers (84.4 and 84.1 cm(2), respectively) than for BM- and HE-sired steers (80.8 and 80.2 cm(2), respectively). A greater (P < 0.05) percentage of carcasses from AN-sired steers graded USDA Choice (69%) than other sire breeds (17 to 47%) except HE (52%). Carcass yield of boneless, totally trimmed retail product was least (P < 0.05) for AN-sired steers (60.1%) and greatest (P < 0.05) for RO- and BO-sired steers (64.4 to 63.5%). Considering all measurements, AN LM tended to be more tender and BM LM tended to be least tender. American composite breeds BM and BR were heavier, fatter, lesser yielding, with similar marbling scores but less tender LM than BO and RO. Angus carcasses were similar in size, fatter, lesser yielding, with more marbling and more tender LM compared with BM and BR. Bonsmara and RO provide tropically adapted germplasm and produce carcasses that are lighter, leaner, greater yielding, with similar marbling and LM that tend to be more tender than carcasses from BM and BR.

Associations of polymorphisms in the promoter I of bovine acetyl-CoA carboxylase-alpha gene with beef fatty acid composition

The objectives of this study were to identify single nucleotide polymorphisms (SNPs) in the promoter I (PI) region of the bovine acetyl-CoA carboxylase-alpha (ACACA) gene and to evaluate the extent to which they were associated with lipid-related traits. Eight novel SNPs were identified, which were AJ276223:g.2064T>A (SNP1), g.2155C>T (SNP2), g.2203G>T (SNP3), g.2268T>C (SNP4), g.2274G>A (SNP5), g.2340A>G (SNP6), g.2350T>C (SNP7) and g.2370A>G (SNP8). Complete linkage disequilibrium was observed among SNP1, 2, 4, 5, 6 and 8. Phenotypic data were collected from 573 cross-bred steers with six sire breeds, including Hereford, Angus, Brangus, Beefmaster, Bonsmara and Romosinuano. The genotypes of SNP1/2/4/5/6/8 were significantly associated with adjusted backfat thickness. The genotypes of SNP3 were significantly associated with triacylglycerol (TAG) content and fatty acid composition of longissimus dorsi muscle (LM) in Brangus-, Romosinuano- and Bonsmara-sired cattle. Cattle with g.2203GG genotype had greater concentrations of TAG, total lipid, total saturated fatty acid and total monounsaturated fatty acid than did cattle with g.2203GT genotype. The genotypes of SNP7 were significantly associated with fatty acid composition of LM. Cattle with genotype g.2350TC had greater amounts of several fatty acids in LM than did cattle with genotype g.2350CC. Our results suggested that the SNPs in the PI region of ACACA gene are associated with variations in the fatty acid contents in LM.

Effect of postweaning growth and bulls selected for extremes in retail beef yield and intramuscular fat on progeny liveweight and carcass traits

The present study is a component of a multi-site experiment, using Bos taurus cattle generated at four locations across southern Australia, designed to examine postweaning growth pathways for progeny whose sires were extreme in retail beef yield and intramuscular fat. Treatment and interaction effects on beef production and meat quality were examined within and across sites. The present paper describes the effect of postweaning growth and sire carcass type on liveweight and carcass traits at the Hamilton site. Angus sires selected on estimated breeding values for extremes in retail beef yield (RBY%), intramuscular fat (IMF%) (estimated breeding values for IMF% are derived by using live-animal ultrasound scanning) or both and sire breed types considered to be more extreme in those traits (Limousin, and Belgian Blue for yield, and Wagyu for intramuscular fat) were joined to crossbred and straight-bred cows. After weaning, the resultant 645 steer and heifer progeny were grown on a fast and slow growth path to ~550 kg and slaughtered, averaging 0.68 kg/day and 22.2 months, and 0.49 kg/day and 27.8 months for growth rate and age at slaughter, respectively. Growth path, sire carcass type and sex affected carcass traits; however, there were no sire carcass type by growth treatment interactions. The fast growth-path cattle were fatter, had more intramuscular fat (measured chemically), a higher Meat Standards of Australia (MSA) USA and AUS marble score, and a higher predicted MSA eating-quality score. Progeny of Wagyu sires were lighter at weaning and slaughter and had a lower hot standard carcass weight than the other sire carcass types. The Belgian Blue and Limousin progeny had a higher dressing percentage, a higher RBY% and a lower P8 and rib-fat depth and lower IMF% than the other sire breed types. Progeny of the high RBY% Angus had a lower rib-fat depth, a lower IMF% and higher RBY% than those selected for high IMF%. There was no difference in IMF% between the Wagyu or the high IMF% Angus. Progeny from the Belgian Blue, Limousin and Wagyu had a larger eye muscle area than the other sire breeds. The results indicate that simultaneous selection for supposedly antagonistic traits of IMF% and RBY% would result in carcass having high values of both measurements. Females were lighter than steers at slaughter, had a lower hot standard carcass weight, were fatter at the P8 and rib, and had a higher marble score and IMF%, a lower yield and a lower MSA-predicted eating-quality score than did steers. There was no interaction between postweaning growth and sire carcass type. These results indicate that with the use of appropriate sire carcass types and BREEDPLAN, and post-weaning nutrition, beef producers can confidently change carcass parameters to suit market specifications.

Evaluation of carcass characteristics of Bos indicus and tropically adapted Bos taurus breeds selected for postweaning weight

Data from 9 studies were compiled to evaluate the effects of 20 yr of selection for postweaning weight (PWW) on carcass characteristics and meat quality in experimental herds of control Nellore (NeC) and selected Nellore (NeS), Caracu (CaS), Guzerah (GuS), and Gir (GiS) breeds. These studies were conducted with animals from a genetic selection program at the Experimental Station of Sertãozinho, São Paulo State, Brazil. After the performance test (168 d postweaning), bulls (n = 490) from the calf crops born between 1992 and 2000 were finished and slaughtered to evaluate carcass traits and meat quality. Treatments were different across studies. A meta-analysis was conducted with a random coefficients model in which herd was considered a fixed effect and treatments within year and year were considered as random effects. Either calculated maturity degree or initial BW was used interchangeably as the covariate, and least squares means were used in the multiple-comparison analysis. The CaS and NeS had heavier (P = 0.002) carcasses than the NeC and GiS; GuS were intermediate. The CaS had the longest carcass (P < 0.001) and heaviest spare ribs (P < 0.001), striploin (P < 0.001), and beef plate (P = 0.013). Although the body, carcass, and quarter weights of NeS were similar to those of CaS, NeS had more edible meat in the leg region than did CaS bulls. Selection for PWW increased rib-eye area in Nellore bulls. Selected Caracu had the lowest (most favorable) shear force values compared with the NeS (P = 0.003), NeC (P = 0.005), GuS (P = 0.003), and GiS (P = 0.008). Selection for PWW increased body, carcass, and meat retail weights in the Nellore without altering dressing percentage and body fat percentage.

Evolution of the Meat Standards Australia (MSA) beef grading system

The Australian Beef Industry identified variable eating quality as a major contributor to declining beef consumption in the early 1990s and committed research funding to address the problem. The major issue was the ability to predict the eating quality of cooked beef before consumption. The Meat Standards Australia (MSA) program developed a consumer testing protocol, which led to MSA grading standards being defined by consumer score outcomes. Traditional carcass grading parameters proved to be of little value in predicting consumer outcomes. Instead a broader combination of factors forms the basis of an interactive prediction model that performs well. The grading model has evolved from a fixed parameter ‘Pathway’ approach, to a computer model that predicts consumer scores for 135 ‘cut by cooking method’ combinations for each graded carcass. The body of research work conducted in evaluating critical control points and in developing the model predictions and interactions has involved several Australian research groups with strong support and involvement from the industry.

Genetic correlations between live yearling bull and steer carcass traits adjusted to different slaughter end points. 2. Carcass fat partitioning

Partial carcass dissection data from 1,031 finished crossbred beef steers were used to calculate heritabilities and genetic correlations among subcutaneous, intermuscular, and body cavity fat percentage and marbling score adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant endpoints. Genetic correlations were also calculated among these fat partitions with live growth and ultrasound traits evaluated in yearling beef bulls (n = 2,172) and steer carcass measurements. Heritabilities of the different fat partitions ranged from 0.22 (marbling score-constant body cavity fat) to 0.46 (HCW-constant marbling score). Genetic correlations between subcutaneous fat and intermuscular fat (rg = 0.16 to 0.32) and between intermuscular fat and body cavity fat (rg = 0.38 to 0.50) were more highly associated than subcutaneous fat and body cavity fat (rg = -0.08 to 0.05), indicating that fat depots are not under identical genetic control. Adjusting fat depots to different end points affected the magnitude but usually not the sign of the genetic correlations. Bull postweaning gain was associated with intermuscular (-0.24 to -0.35), body cavity (-0.24 to -0.29), and marbling fat (-0.24 to -0.39) in steers. Bull hip height was associated with body cavity (-0.20 to -0.29) and marbling fat (-0.20 to -0.47) in steers. Bull ultrasound fat depth was associated with subcutaneous (0.11 to 0.29), intermuscular (0.05 to 0.36), body cavity (0.27 to 0.49), and marbling fat (0.27 to 0.73) in steers. Bull ultrasound intramuscular fat percentage was associated with subcutaneous (-0.22 to -0.44) and intermuscular fat (-0.06 to 0.31) in steers. Bull ultrasound LM area was associated with body cavity (-0.25 to -0.31) and marbling fat (-0.25 to -0.30) in steers. Ultrasound LM width measurements were negatively correlated with subcutaneous fat (rg = -0.09 to -0.18), intermuscular fat (rg = -0.53 to -0.61), body cavity fat (rg = -0.63 to -0.69), and marbling score (rg = -0.75 to -0.87) at slaughter age-, HCW-, and fat depth-constant endpoints; correlations were generally lower at a marbling score-constant end point (rg = 0.07 to -0.49). Ultrasound indicator traits measured in seedstock may be useful in altering fat partitioning in commercial beef carcasses.

Genetic parameters for growth and carcass traits of Brahman steers

Spring-born purebred Brahman bull calves (n = 467) with known pedigrees, sired by 68 bulls in 17 private herds in Louisiana, were purchased at weaning from 1996 through 2000 to study variation in growth, carcass, and tenderness traits. After purchase, calves were processed for stocker grazing on ryegrass, fed in a south Texas feedlot, and processed in a commercial facility. Carcass data were recorded 24 h postmortem. Muscle samples and primal ribs were taken to measure calpastatin activity and shear force. An animal model was used to estimate heritability, genetic correlations, and sire EPD. Relatively high heritability estimates were found for BW at slaughter (0.59 +/- 0.16), HCW (0.57 +/- 0.15), LM area (0.50 +/- 0.16), yield grade (0.46 +/- 0.17), calpastatin enzyme activity (0.45 +/- 0.17), and carcass quality grade (0.42 +/- 0.16); moderate heritability estimates were found for hump height (0.38 +/- 0.16), marbling score (0.37 +/- 0.16), backfat thickness (0.36 +/- 0.17), feedlot ADG (0.33 +/- 0.14), 7-d shear force (0.29 +/- 0.14), and 14-d shear force (0.20 +/- 0.11); relatively low heritability estimates were found for skeletal maturity (0.10 +/- 0.10), lean maturity (0.00 +/- 0.07), and percent KPH (0.00 +/- 0.07). Most genetic correlations were between -0.50 and +0.50. Other genetic correlations were 0.74 +/- 0.27 between calpastatin activity and 7-d shear force, 0.72 +/- 0.25 between calpastatin activity and 14-d shear force, (0.90 +/- 0.30 between yield grade and 7-d shear force, and -0.82 +/- 0.27 between backfat thickness and 7-d shear force. Heritability estimates and genetic correlations for most traits were similar to estimates reported in the literature. Sire EPD ranges for carcass traits approached those reported for sires in other breeds. The magnitude of heritability estimates suggests that improvement in carcass yield, carcass quality, and consumer acceptance traits can be made within the Brahman population.

Association of markers in the bovine CAPN1 gene with meat tenderness in large crossbred populations that sample influential industry sires

Two previously identified single-nucleotide polymorphism markers located within the micromolar calcium-activated neutral protease gene (CAPN1) were evaluated for their association with variation in meat tenderness using one commercial sample of Simmental x Angus crossbred calves and one multibreed, crossbred research herd. The commercial sample included 362 animals sired by 23 registered Simmental bulls bred to unregistered Angus cows and represented current industry animals in which to test the predictive merit of the markers. The second sample was a research herd including 564 steers from the Germplasm Evaluation Cycle VII population at the U.S. Meat Animal Research Center, produced with semen from popular sires of the seven Bos taurus beef breeds with the most registrations in the United States (Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental) on Angus, Hereford, and MARC III cows. These animals form a relatively outbred population that constituted a stringent test of the predictive merit of the genetic markers, although small groups were half-sibs. Warner-Bratzler shear force measurements were used to determine tenderness phenotypes for all animals. The populations were genotyped for two markers that predict variation at amino acid positions 316 and 530 of the mu-calpain polypeptide, produced by the CAPN1 gene. Minor allele frequencies for markers 316 and 530 in the commercial sample were 0.17 and 0.37, respectively, and in the Cycle VII animals, were 0.20 and 0.28, respectively. Both markers showed association with shear force in the commercial sample (P = 0.04) and the Cycle VII population (P = 0.02), supporting the hypothesis that they represent potential markers to aid selection for improved meat tenderness in commercial populations of beef cattle in the United States.

The relationship of physiological maturity and marbling judged according to Korean grading system to meat quality traits of Hanwoo beef females

Fifty seven carcasses from Hanwoo beef females were randomly selected by official meat graders and were sorted into three levels of maturity and marbling. Carcass data was collected for back fat thickness, longissimus area, carcass weight, meat colour, fat colour, marbling score, yield and quality grades. Mature carcasses had more yellow fat, coarser texture, a larger longissimus muscle area and lower quality grades and marbling scores (P<0.05). Carcasses with a higher marbling score had thicker fat and a higher quality grade. Carcasses with low marbling had a higher yield grade and a coarser texture (P<0.05). Higher marbling scores corresponded with lower cook and drip loss values for longissimus steaks. As the maturity of carcass was increased, the redness and lightness of meat and the yellowness of fat all tended to increase. Tenderness, flavour and overall acceptability scores for the older maturity group were lower than for younger and intermediate groups. Marbling was significantly (P<0.01) correlated with quality grade, crude fat content, cook and drip losses, and Warner-Bratzler shear force. The maturity level was also significantly (P<0.01) correlated with quality grade, fat colour, texture score, number of calves produced and milk teeth, meat redness and yellowness, fat yellowness, and Warner-Bratzler shear force. Results indicate that a low marbling group and older maturity group based on Korean grading system could negatively influence carcass traits and beef qualities of Hanwoo beef female.