Wagyu Breeds Research Articles

Muscle biopsy long-chain omega-3 polyunsaturated fatty acid compositions, IMF and FMP in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford, and Wagyu Beef Cattle

BackgroundWe investigated breed and gender variations in the compositions of long-chain (≥ C20) omega-3 polyunsaturated fatty acids (LC omega-3 PUFA), fat melting point (FMP) and intramuscular fat (IMF) contents in biopsy samples of the M. longissimus dorsi muscle of grazing beef cattle. The hypothesis that biopsy compositions of health-beneficial LC omega-3 PUFA, FMP and IMF in a pasture-based production system will vary with breed, was tested. Muscle biopsies were taken from 127 yearling pasture-based Angus, Hereford, and Wagyu heifers and young bulls exclusive to the Australian Bowen Genetics Forest Pastoral breeding stud averaging 12 ± 2.43 months of age and under the same management routine.ResultsBreed had a significant influence on IMF, FMP, and the compositions of oleic acid, α-linolenic acid (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA), docosapentaenoic (DPA), and total EPA + DHA + DPA in the M. longissimus dorsi muscle biopsies (P ≤ 0.03). The Wagyu breed had the highest (11.1%) and Hereford the lowest (5.9%) IMF (P = 0.03). The reverse trend was observed in FMP values where the Hereford breed had the highest (55 °C), Angus intermediate (46.5 °C), and Wagyu the lowest (33 °C) FMP. The Wagyu and Angus breeds had similar oleic fatty acid (18:1n-9) content, while the Hereford breed had the lowest (P < 0.01). The highest ALA, DPA, total EPA + DHA, total EPA + DHA + DPA and total ALA + EPA + DHA + DPA contents were detected in the Wagyu breed (P ≤ 0.03). The Hereford had similar EPA and DPA contents to the Angus (P ≥ 0.46). Total EPA + DHA + DPA contents in Wagyu, Angus, and Hereford were 28.8, 21.5, and 22.1 mg/100g tissue (P = 0.01), respectively. Sex was an important source of variation that influenced LC omega-3 PUFA composition, FMP and IMF, where yearling heifers had higher IMF (11.9% vs 5.3%), lower FMP (33°C vs 37°C), and higher LC omega-3 PUFA than bulls.ConclusionAll the results taken together indicate that the Wagyu breed at 28.8 mg/100g tissue, was the closest to meeting the Australia and New Zealand recommended source level threshold of 30 mg/100g tissue of health-beneficial ≥ C20 omega-3 FA content. Since gender was a significant determinant of LC omega-3 PUFA composition, IMF content and FMP, it should be factored into enhancement strategies of healthy meat eating quality traits in grazing cattle. These findings also suggest that the Bowen Genetics Forest Pastoral beef cattle studs are important sources of LC omega-3 PUFA that can be used to cover the deficit in these health claimable fatty acids in Western diets.

PMEL p.L18del associates with beef quality of Kumamoto sub-breed of Japanese Brown cattle.

Japanese Brown cattle is the second most popular breed among Wagyu breeds and raised mainly in Kumamoto and Kochi Prefectures. Typical coat color of the Kumamoto sub-breed is solid brown, but individuals with diluted coat color are sometimes born. We previously detected four SNPs in PMEL gene and identified p.L18del as the causative polymorphism of this diluted phenotype. The current study examined the association between the SNPs in PMEL gene and carcass traits of the Kumamoto sub-breed. Our association analysis revealed that p.L18del had significant effects on BMS (p = 0.0263), meat brightness (p = 0.0179), meat firmness (p = 0.0102), and meat texture (p = 0.0252) and that del allele of this SNP might be useful to improve these carcass traits.

Wagyu Feeder Check: A genomic-based tool to identify performance differences of Australian Wagyu and Wagyu crossed cattle

Context Wagyu Feeder Check is a genomic-based tool designed to provide genomic estimated breeding values (GEBV) for five feedlot growth and carcase traits. At present, Wagyu Feeder Check is based on a reference population of 8316 genotyped and phenotyped Australian fullblood (FB; N = 2120) Wagyu and Wagyu-crossed (XB; N = 6196) cattle, principally Wagyu × Angus F1 animals. Aims We provide technical details behind the development of the Wagyu Feeder Check and validate the ability of its GEBV to predict differences in performance of Wagyu cattle in daily weight gain at feedlot, carcase weight, carcase eye muscle area, carcase marbling score and carcase rump fat at the P8 site. Methods Data supplied from eight commercial supply chains across Australia was used to generate GEBV using mixed-model equations that incorporated a genomic relationship matrix build with 82 504 autosomal markers. The bias, dispersion, and accuracy of the GEBV were evaluated using a four-way cross-validation scheme where, in each turn, the phenotypes from a random 1549 (or 25%) XB cattle were set as missing. Key results The genomic estimate of the Wagyu content in the FB and XB population averaged 99.12% and 59.55%, respectively, and with most of the non-Wagyu content associated with Angus. The estimates of heritability (± s.e.) were 0.497 ± 0.016, 0.474 ± 0.004, 0.347 ± 0.014, 0.429 ± 0.003 and 0.422 ± 0.003 for daily weight gain at feedlot, carcase weight, eye muscle area, marbling and rump fat, respectively. Averaged across the four XB validation populations, the accuracy of GEBV was 0.624, 0.634, 0.385, 0.620, and 0.526 for the same set of traits. Conclusions Genomic predictions generated by Wagyu Feeder Check can predict differences in feedlot and carcase performance of Australian Wagyu cattle. Given the large content of Angus in the XB population, further research is required to determine the predictive ability of GEBV in Wagyu × Bos indicus and Wagyu × dairy animals. Implications Commercial feedlot operators finishing animals with a strong Wagyu breed component will benefit from using Wagyu Feeder Check for decision making.

Evaluation of sperm and hormonal assessments in Wagyu, Nellore, and Angus bulls.

Wagyu bulls are known to have a highly exacerbated libido, as shown by the intense sexual interest of young calves. Therefore we believe that Wagyu male animals have specialized Sertoli and Leydig cells that are directly involved with the sexual precocity in this breed as mature bulls have a small scrotal circumference. This study aimed to evaluate whether there were differences in the hormone and sperm characteristics of Wagyu bulls compared with the same characteristics of subspecies Bos indicus and Bos taurus sires. Frozen-thawed semen from Wagyu, Nellore, and Angus sires were analyzed for sperm kinetics (computer-assisted sperm analysis), plasma membrane integrity, chromatin integrity, acrosome status, mitochondrial activity, lipid peroxidation and hormone [luteinizing hormone (LH) and testosterone] serum concentration. The results showed that Wagyu had lower total motility and an increased number of sperm with no motility when compared with Nellore and Angus bulls. Wagyu breed did not differ from those breeds when considering plasma and acrosome membranes integrity, mitochondrial potential, chromatin resistance, sperm lipid peroxidation or hormone (LH and testosterone) concentrations. We concluded that Wagyu sires had lower total motility when compared with Nellore and Angus bulls. Wagyu breed did not differ from these breeds when considering plasma and acrosome membranes integrity, mitochondrial potential, chromatin resistance, sperm lipid peroxidation, or hormone (LH and testosterone) concentrations.

Causative alleles for chondrodysplastic dwarfism, factor XI deficiency, and factor XIII deficiency in the Kumamoto sub-breed of Japanese Brown cattle.

Japanese Brown cattle are the second most popular Wagyu breed, and the Kumamoto sub-breed shows better daily gain and carcass weight. One of the breeding objectives for this sub-breed is to reduce genetic defects. Chondrodysplastic dwarfism and factor VIII deficiency have been identified as genetic diseases in the Kumamoto sub-breed. Previously, we detected individuals in the Kumamoto sub-breed with causative alleles of genetic diseases identified in Japanese Black cattle. In the current study, 11 mutations responsible for genetic diseases in the Wagyu breeds were analyzed to evaluate the risk of genetic diseases in the Kumamoto sub-breed. Genotyping revealed the causative mutations of chondrodysplastic dwarfism, factor XI deficiency, and factor XIII deficiency and suggested the appearance of affected animals in this sub-breed. DNA testing for these diseases is needed to prevent economic loses in beef production using the Kumamoto sub-breed.

A conserved haplotype in Wagyu cattle contains RAB4A whose encoded protein regulates glucose trafficking in muscle and fat cells

The Wagyu breed of taurine cattle possess favourable genetics for intramuscular fat (IMF) but genomic loci associated with the trait remain under characterised. Here, we report the identification of a previously unidentified genomic region possessing a particular haplotype structure in Wagyu. Through deployment of a genome-wide haplotype detection analysis that captures regions conserved in a target population but not other populations we screened 100 individual Wagyu and contrasted them with 100 individuals from two independent comparison breeds, Charolais and Angus, using high-density SNPs. An extreme level of Wagyu conservation was assigned to a single genomic window (spanning genomic coordinates BTA28:41088-300265bp). In fact, a five-SNP region spanning 27096bp is almost perfectly conserved among the 100 Wagyu individuals assayed and partially overlaps RAB4A. Focussing in, two consecutive SNPs (genomic coordinates 236949 and 239950) are apparently fixed within the Wagyu (BB and AA respectively), but at mixed frequencies in the other two breeds. These SNPs are located in the two introns straddling exon 7. In a separate analysis using the 1000 Bulls database, we found that, coincident with exon 7 of RAB4A first allele frequencies were highest in the high IMF Japanese Native (Wagyu) breeds (0.78) and lowest in the low IMF indicine breeds (Nelore and Brahman), with intermediate marbling breeds (Angus and Charolais) assigned intermediate rankings (0.42). RAB4A is known to encode a protein that regulates intracellular trafficking of the insulin-regulated glucose transporter GLUT4. RAB4A can be considered an attractive new positional candidate for IMF development.

Evaluation of inbreeding and genetic diversity in Japanese Shorthorn cattle by pedigree analysis.

The Japanese Shorthorn is a Japanese Wagyu breed maintained at a small population size. We assessed the degree of inbreeding and genetic diversity among Japanese Shorthorn cattle using pedigree analysis. We analyzed the pedigree records of registered Japanese Shorthorn born between 1980 and 2018, after evaluating the pedigree completeness. The average of the actual inbreeding coefficients increased at the same rates annually from approximately 1.5% in 1980 to 4.2% in 2018 and was higher than the expected inbreeding coefficients over time. The effective population size based on the individual coancestry rate largely decreased from 127.8 in 1980 to 82.6 in 1999, and then remained almost constant at approximately 90. Three effective numbers of ancestors decreased over time until 1995, then remained almost constant. In particular, the effective number of founder genomes (N ge ) decreased from 43.8 in 1980 to 11.9 in 2018. The index of genetic diversity based on N ge decreased from 0.99 in 1980 to 0.96 in 2018 due to genetic drift in non‐founder generations. Changes in inbreeding and genetic diversity parameters were similar between Japanese Shorthorn and other Japanese Wagyu breeds, but the magnitude of the changes was lower in the Japanese Shorthorn.

Mass transfer in beef: effect of crossbreeding and ultrasound application

ABSTRACT: Cuts of muscle (biceps femoris) from three crossbreeds between the Nelore, Angus and Wagyu breeds of cattle (Crossbreed 1 (C1): ½ Angus and ½ Nelore; Crossbreed 2 (C2): ¾ Angus and ¼ Nelore; Crossbreed 3 (C3): ½ Wagyu, ¼ Nelore and ¼ Angus) were characterized by their chemical composition, pH, water activity and lipid oxidation. The cuts were submitted to wet brining in a 5 % NaCl concentration at 5 °C with either static brine (SB) or brine assisted with ultrasound (US). Samples of the treatments were taken after 30, 60, and 120 min of wet brining for later analysis. The experimental data were adjusted using the Peleg and Page models, and the Page template best described the experimental data. The crossbreeding did not affect the water and ash content; however, it significantly affected the levels of lipids and proteins. C3 presented higher fat content than C2, which, in turn, was higher than C1. C1 had higher protein content than C2, which had more protein than C3. When ultrasound was applied, crossbreeding influenced the water content and the water absorption rate during brining, which had the highest values for the highest protein content. The crossbreeding and ultrasound application also affected the NaCl content of the cuts. However, only ultrasound application increased the rate of NaCl absorption during wet brining. The results demonstrate that ultrasound accelerates the mass transfer in wet brining of the cuts of beef, regardless of the crossbreeds studied.

The Outcome and Economic Viability of Embryo Production Using IVF and SOV Techniques in the Wagyu Breed of Cattle.

The Japanese black cattle breed (Wagyu) has an improved metabolism, which allows them to have a higher marbling score when compared with other cattle breeds. However, this may affect other aspects of the animal’s physiology, including hormone secretion and their reproductive success, such as their response to synchronization protocols and embryo production. Therefore, the objectives of this study were to test a superovulation protocol (SOV) developed with low doses of FSH and to evaluate the outcome and economic viability of embryo production using the SOV and in vitro fertilization (IVF) approaches in the Wagyu cattle breed. For that, ten Wagyu cows were submitted to five SOVs over a period of 15 months using a standard protocol: CIDR + 3 mg estradiol benzoate (D0), 35 mg FSH (Folltropin®) a.m. and p.m. (D4), 35 mg Folltropin® a.m. and 20 mg p.m. (D5), 20 mg Folltropin® a.m. and 10 mg p.m. (D6), 10 mg Folltropin® and 0.5 mg cloprostenol, both a.m. and p.m., + CIDR removal (D7), 0.05 mg GnRH + insemination 12 and 24 h after (D8) and embryo collection + 0.5 mg of cloprostenol (D16). Thirty days after each SOV, a follicular aspiration was conducted to produce IVF embryos without any pre-synchronization using standard semen in the same group of animals. The average number of embryos produced was 7.63 ± 5.61 (SOV) and 4.52 ± 2.44 (IVF) (p = 0.303). There was no significant correlation between the number of embryos produced by the different techniques (SOV and IVF), indicating that cows that respond well to SOV did not respond well to IVF and vice versa (r = 0.379, p = 0.529). The total cost of each embryo produced by SOV was R$215.00 and R$410.00 for IVF. Therefore, cows that produce less than five embryos by SOV are not economically viable due their lack of response to FSH, and the use of IVF in those animals may be more effective.

280 Quality grading using color and electrical conductivity of beef

Abstract Four sources of beef were used to determine if the degree of variance in color (Hunter LH) and electrical conductivity (EC) measures correlate to quality grade. It also tested the reliability of the Varian spectrophotometer machine for color scores on beef. Source 1 (S1) samples varied in cuts that were frozen then thawed. S2 – S4 were delivered whole and cut into 16 individual, 1-inch thick samples. Source 2 (S2) was a whole boneless ribeye and choice grade; Source 3 (S3) was a whole strip loin, Wagyu breed and prime grade; Source 4 (S4) was a whole strip loin, Akaushi breed and prime grade. All color measurements (n = 48) were taken on raw samples. EC (n = 48) was measured in microsiemens (μS) for 120s with sampling rate of two measures per s. An emulsified meat slurry solution was placed into a 3in wide silicon vessel with copper electrodes attached to both sides, and placed into plastic container connected to a digital multimeter. Analysis of variance (ANOVA) was used for data analysis on color &amp; EC replications and total color &amp; EC means and performed across S1 then S2 – S4. Color results across color mean replications for individual samples were non-significant (P &amp;gt; 0.05, 95% confidence level). Source color means for S1=33.6873, S2=55.4319, S3=47.8122 &amp; S4=53.5633. S1 had the lowest LH mean compared to S2-S4 and presumed to be a result of myoglobin state. These data indicate reliability of the Varian color machine as method for scoring steaks. EC results showed prime grades S3 and S4 had lower scores compared to S1 and S2 with EC means of S1=24.8043, S2=63.5294, S3=17.0451 &amp; S4=18.9656. S3 &amp; S4 both had significant correlations (P &amp;lt; 0.05) between EC and color scores indicating EC and color correlations can be useful in quality grading of beef.

222 Effective donor selection before superovulation treatment for Japanese Black beef cattle

Japanese Black beef cattle (JBBC) are a leading Wagyu breed in Japan. Embryo transfers are being used to improve JBBC, a sturdy, fast-maturing breed prized for its marbled beef; however, relevant donor selection techniques have not been fully established. Accordingly, in this study, in order to produce embryos efficiently, we aimed to investigate donor selection techniques based on follicle counts at different time points (Experiment 1) and an associated genetic marker (Experiment 2). Statistical differences were evaluated with Student's t-test or Welch's t-test, regarding P&amp;lt;0.05 as significant. In Experiment 1, we initially targeted 57 JBBCs for evaluation. Their follicle counts were determined by ultrasound 3 days before the start of superovulation (pre), close to the time of follicular wave emergence, and they were grouped according to number of follicles (0-19, 20-29, 30-39, and ≥40). Each cow was administered a tapered dose of FSH-R (20 AU) for superovulation, and then subjected to AI with cryopreserved semen from bulls of proven fecundity. Embryos were collected 7 days after AI by non-surgical intrauterine reflux. Post-AI follicle counts were done before ovulation and did not differ significantly from pre-superovulation follicle count in any group (range: −1.09 to 0.61). We then targeted a further 12 JBBC undergoing superovulation and AI with the same procedures, for counting of follicles at 30 days before (Day −30) embryo recovery (ER), pre-superovulation, and AI, and counting of corpora lutea and large follicles at ER, to investigate correlations between counts. We used decision coefficient (R2), regarding R2 ≥ 0.5 as significant. We found positive correlations (R2) at Day −30 with pre-superovulation (0.91), AI (0.63), and ER (0.63), and at pre-superovulation with AI (0.69) and ER (0.74). In Experiment 2, we targeted 69 JBBCs for detection of mutations in the GRIA1 gene, which encodes inotropic glutamate receptor AMPA1 with a known association with ovulation rate, and embryo yield measurements. DNA obtained from blood was subject to microsatellite polymorphism analysis, for mutations at base 917 of GRIA1 exon 7. We identified 33 cows (48%) as bearers of the wild-type allele (GG), 29 cows (42%) as bearers of the heterozygous mutation (GA), and seven cows (10%) as bearers of the homozygous mutation (AA). Average embryo yield was highest in wild-type cows, followed by heterozygous mutants and then homozygous mutants, and was significantly lower for homozygous mutants than for the other two types. Our study results demonstrated that follicle count before superovulation and GRIA1 gene analysis have utility for selecting donors for embryo transfer in JBBC. Furthermore, follicle counts at the early time point of 30 days before ER can be a useful indicator for this selection.

Comparisons of Beef Fatty Acid and Amino Acid Characteristics between Jeju Black Cattle, Hanwoo, and Wagyu Breeds.

Jeju black cattle are known as one of Korea’s traditional cattle. However, Hanwoo is more well-known to Korean meat consumers as representative beef cattle. Despite the popularity of these two breeds, comparison of the nutritional characteristics between Jeju black cattle and Hanwoo have not been studied. Here, we compared the fatty acid and amino acid characteristics between two Korean traditional cattle and Wagyu breeds. A total of 62 cattle were used in this study. The Jeju black cattle beef had significantly higher unsaturated fatty acids than Hanwoo (p<0.05). Savory fatty acids, including oleic acid were also higher than in Hanwoo cattle (p<0.05). The negative flavor fatty acids, such as palmitic acid were significantly lower than in Hanwoo (p<0.001). On the other hand, linoleic acid which imparts a negative flavor was higher than Hanwoo (p<0.05). Amino acids, including alanine and glutamine, usually representative of the umami taste were present in significantly higher proportions in Jeju black cattle (p<0.05). In addition, bitter tasting amino acids, including valine, leucine, isoleucine, and methionine were lower in Jeju black cattle beef than in Hanwoo (p<0.05, p<0.001, p<0.001, and p<0.001 each). Taken together, our results suggest that Jeju black cattle beef had higher savory flavor and umami taste which affected consumers preference for the meat.

Genetics of Marbling in Wagyu Revealed by the Melting Temperature of Intramuscular and Subcutaneous Lipids.

Extreme marbling or intramuscular deposition of lipid is associated with Wagyu breeds and is therefore assumed to be largely inherited. However, even within 100% full blood Wagyu prepared under standard conditions, there is unpredictable scatter of the degree of marbling. Here, we evaluate melting temperature (Tm) of intramuscular fat as an alternative to visual scores of marbling. We show that “long fed” Wagyu generally has Tm below body temperature but with a considerable range under standardized conditions. Individual sires have a major impact indicating that the variation is genetic rather than environmental or random error. In order to measure differences of lower marbling breeds and at shorter feeding periods, we have compared Tm in subcutaneous fat samples from over the striploin. Supplementary feeding for 100 to 150 days leads to a rapid decrease in Tm of 50% Red Wagyu (Akaushi) : 50% European crosses, when compared to 100% European. This improvement indicates that the genetic effect of Wagyu is useful, predictable, and highly penetrant. Contemporaneous DNA extraction does not affect the measurement of Tm. Thus, provenance can be traced and substitution can be eliminated in a simple and cost-effective manner.

Low mitochondrial DNA diversity of Japanese Polled and Kuchinoshima feral cattle.

This study aims to estimate the mitochondrial genetic diversity and structure of Japanese Polled and Kuchinoshima feral cattle, which are maintained in small populations. We determined the mitochondrial DMA (mtDNA) displacement loop (D-loop) sequences for both cattle populations and analyzed these in conjunction with previously published data from Northeast Asian cattle populations. Our findings showed that Japanese native cattle have a predominant, Asian-specific mtDNA haplogroup T4 with high frequencies (0.43-0.81). This excluded Kuchinoshima cattle (32 animals), which had only one mtDNA haplotype belonging to the haplogroup T3. Japanese Polled showed relatively lower mtDNA diversity in the average sequence divergence (0.0020) than other Wagyu breeds (0.0036-0.0047). Japanese Polled have been maintained in a limited area of Yamaguchi, and the population size is now less than 200. Therefore, low mtDNA diversity in the Japanese Polled could be explained by the decreasing population size in the last three decades. We found low mtDNA diversity in both Japanese Polled and Kuchinoshima cattle. The genetic information obtained in this study will be useful for maintaining these populations and for understanding the origin of Japanese native cattle.

Risk factors for stillbirths and mortality during the first 24 h of life on dairy farms in Hokkaido, Japan 2005–2009

This was a retrospective cohort study using data from the insurance scheme provided by the Japanese Mutual Aid Association (NOSAI). The population of interest comprised all cattle born on NOSAI-client farms in the Japanese prefecture of Hokkaido, Japan for the period 1 April 2005–31 March 2009. The outcome of interest was whether or not at least one calf was stillborn, had died during delivery or died during the first 24 hours of life for a given calving event, termed first 24h mortality risk.A mixed-effects logistic regression model was developed to identify explanatory variables associated with first 24h mortality risk. The final data set comprised details of 1,281,737 calving events on a total of 5172 dairy herds from 19 NOSAI branches located throughout the prefecture of Hokkaido. Throughout the study period 7.68 (95% CI 7.64–7.73) of every 100 calving events had at least one calf that was either stillborn, dead at the time of delivery or dead during the first 24h of life.Factors that were positively associated with an increase in first 24h mortality risk included delivery during the colder months of the year (November–March), being of Wagyu breed, having a multipara dam, multiple (as opposed to single) birth deliveries, and delivery in larger herds. ​After adjusting for the fixed effects included in our multilevel model, 89% of the unexplained variation in first 24h mortality risk was at the calving event level. We propose that the data recording requirements of the NOSAI scheme are extended to include details of calving events (e.g. the presence or absence of dystocia) and details of the way in which calves are managed post delivery. This would allow more subtle risk factors for calf mortality to be identified which, in turn, will lead to refinement of recommendations for calf management during the first 24h of life in this area of Japan.

Evaluation of Beef by Electronic Tongue System TS-5000Z: Flavor Assessment, Recognition and Chemical Compositions According to Its Correlation with Flavor.

The aim of this study was to assess the ability of electronic tongue system TS-5000Z to evaluate meat quality based on flavor assessment, recognition and correlation with the meat chemical composition. Meat was sampled from eighteen beef cattle including 6 Wagyu breed cattle, 6 Angus breed cattle and 6 Simmental breed cattle. Chemical composition including dry matter, crude protein, fat, ash, cholesterol and taurine and flavor of the meat were measured. The results showed that different breed cattle had different chemical compositions and flavor, which contains sourness, umami, saltiness, bitterness, astringency, aftertaste from astringency, aftertaste from bitterness and aftertaste from umami, respectively. A principal component analysis (PCA) showed an easily visible separation between different breeds of cattle and indicated that TS-5000Z made a rapid identification of different breeds of cattle. In addition, TS-5000Z seemed to be used to predict the chemical composition according to its correlation with the flavor. In conclusion, TS-5000Z would be used as a rapid analytical tool to evaluate the beef quality both qualitatively and quantitatively, based on flavor assessment, recognition and chemical composition according to its correlation with flavor.

Modeling of crossbred cattle growth, comparison between cubic and piecewise random regression models

Two analyses, cubic and piecewise random regression, were conducted to model growth of crossbred cattle from birth to about two years of age, investigating the ability of a piecewise procedure to fit growth traits without the complications of the cubic model. During a four-year period (1994-1997) of the Australian "Southern Crossbreeding Project", mature Hereford cows (N = 581) were mated to 97 sires of Angus, Belgian Blue, Hereford, Jersey, Limousin, South Devon, and Wagyu breeds, resulting in 1141 steers and heifers born over four years. Data included 13 (for steers) and eight (for heifers) live body weight measurements, made approximately every 50 days from birth until slaughter. The mixed model included fixed effects of sex, sire breed, age (linear, quadratic and cubic), and their interactions between sex and sire breed with age. Random effects were sire, dam, management (birth location, year, post-weaning groups), and permanent environmental effects and for each of these when possible, their interactions with linear, quadratic and cubic growth. In both models, body weights of all breeds increased over pre-weaning period, held fairly steady (slightly flattening) over the dry season then increased again towards the end of the feedlot period. The number of estimated parameters for the cubic model was 22 while for the piecewise model it was 32. It was concluded that the piecewise model was very similar to the cubic model in the fit to the data; with the piecewise model being marginally better. The piecewise model seems to fit the data better at the end of the growth period.

Characterization and validation of bovine Gonadotripin releasing hormone receptor (GNRHR) polymorphisms

Gonadotropin releasing hormone and its receptor (GNRHR) play a critical role in sexual differentiation and reproduction. Available evidence shows a strong genetic component in the timing of puberty. In bovines, there are significant differences within and among beef breeds in the time when bulls reach puberty. Despite its economic importance, there are not many SNPs or genetic markers associated with this characteristic. The aims of the study were to identify DNA polymorphism in the bovine GNRHR by re-sequencing analysis, determine haplotype phases, and perform a population study in a selected tag SNP in six breeds. Eight SNPs were detected, including: one in the Upstream Regulatory Region (URR), five in the coding regions, and two in non-coding regions. This polymorphism level corresponds to one variant every 249.4 bp and a global nucleotide diversity of 0.385. Two haplogroups comprising nine haplotypes and two linkage blocks were detected. Despite 5 tag SNPs were required to capture all variability, just one SNP allowed to define both haplogroups, and only two SNPs were needed to differentiate the most common haplotypes. An additional taq SNP was necessary to identify both URR variants. Allele-frequency analysis of a selected taq SNP among breeds showed a geographical cline. European Bos taurus breeds had lower frequencies of the C allele than B. indicus type cattle, while Creole cattle and Wagyu breeds had intermediate frequency. There was a significant correlation between frequency profile and timing of puberty among the studied breeds, which seems to suggest that genetic variation within bovine GNRHR gene could explain at least part of the reported variability.

Modeling the relationship between scanned rump and 12th-rib fat in young temperate and tropical bovines: Model development and evaluation1,2

A decision support tool for predicting subcutaneous fat depths called BeefSpecs, based on the Davis growth model (DGM), has been developed by the Cooperative Research Centre for Beef Genetic Technologies. Currently, the DGM predicts 12th-rib fat thickness (RFT, mm). To allow predictions of fat thickness at the P8 rump (P8FT, mm) site, the standard carcass fat measurement in the Australian beef industry, a relationship was developed between ultrasound RFT and P8FT in steers and heifers from temperate (Angus, Hereford, Shorthorn, and Murray Grey) and tropical (Brahman, Belmont Red, and Santa Gertrudis) breed types. Model development involved fitting various combinations of sex, breed type (BrT), BW, age, and RFT to produce 6 models. The models were challenged with data from 3 independent data sets: 1) Angus steers from 2.4 generations of divergent selection for and against residual feed intake; 2) 2 tropically adapted genotypes [Brahman and tropically adapted composites (combinations of Belmont Red, Charbray, Santa Gertrudis, Senepol, and Brahman breeds)]; and 3) a study using sires from Charolais, Limousin, Belgian Blue, and Black and Red Wagyu breeds and 3 genetic lines of Angus to create divergence in progeny in terms of genetic potential for intramuscular fat percent and retail beef yield. When challenged with data from Angus cattle, the mean biases (MB, mm) for models A to F were -1.23, -0.56, -0.56, -0.02, 0.14, and 0.04, and the root mean square errors of predictions (mm) were 1.53, 0.97, 0.97, 0.92, 0.93, and 0.91, respectively. When challenged with data from Brahman cattle, MB were 0.04, -0.22, -0.14, 0.05, -0.11, and 0.02 and root mean square errors of predictions were 1.30, 1.29, 1.27, 1.23, 1.37, and 1.29, respectively. Generally, model accuracy indicated by MB tended to be less for model E, which contained age rather than BW as a covariate. Models B and C were generally robust when challenged with data from Angus, Brahman, and Tropical Composite cattle as well as crossbred cattle with temperate sires. Model D, which did not contain age, performed the most consistently and was selected for inclusion in the DGM: P8FT, mm = -3.6 (+/-0.14) + 1.3 (+/-0.13) x sex + 0.11 (+/-0.13) x BrT + 0.014 (+/-4.8E(-4)) x BW + 0.96 (+/-0.01) x RFT - 0.73 (+/-0.08) x sex x BrT - 3.8E(-3) (+/-4.2E(-4)) x sex x BW - 0.09 (+/-0.01) x sex x RFT + 1.3E(-3) (+/-3.7E(-4)) x BrT x BW + 0.24 (+/-0.01) x BrT x RFT (adjusted R(2) = 0.86; SE = 0.013). Model D has been implemented in BeefSpecs to predict P8FT.

Economic effects of alternate growth path, time of calving and breed type combinations across southern Australian beef cattle environments: feedlot finishing at the New South Wales experimental site

The ‘Regional Combinations’ project and its biophysical outcomes have been described in several other papers in this special edition. The information provided in these papers allows an evaluation of the most profitable beef cattle production systems across different environments in southern Australia. In this paper, the focus is on the New South Wales experimental site where the trial animals were finished in a feedlot. The data identified liveweight gain as the biggest driver of profitability of production. Between growth treatments, there was a large difference in the gross margins before feedlot entry between the ‘fast’ and ‘slow’ treatments favouring the fast-grown animals, even after accounting for the higher cost of producing pasture capable of sustaining faster growth. However, the slow growth treatments consistently outperformed the fast growth treatments in the feedlot. In terms of breeds, the European breed types consistently outperformed the Wagyu breeds. There were no time-of-calving experiments in New South Wales.