Brahman Breeding Research Articles

Accuracies of genomically estimated breeding values from pure-breed and across-breed predictions in Australian beef cattle

BackgroundThe major obstacles for the implementation of genomic selection in Australian beef cattle are the variety of breeds and in general, small numbers of genotyped and phenotyped individuals per breed. The Australian Beef Cooperative Research Center (Beef CRC) investigated these issues by deriving genomic prediction equations (PE) from a training set of animals that covers a range of breeds and crosses including Angus, Murray Grey, Shorthorn, Hereford, Brahman, Belmont Red, Santa Gertrudis and Tropical Composite. This paper presents accuracies of genomically estimated breeding values (GEBV) that were calculated from these PE in the commercial pure-breed beef cattle seed stock sector.MethodsPE derived by the Beef CRC from multi-breed and pure-breed training populations were applied to genotyped Angus, Limousin and Brahman sires and young animals, but with no pure-breed Limousin in the training population. The accuracy of the resulting GEBV was assessed by their genetic correlation to their phenotypic target trait in a bi-variate REML approach that models GEBV as trait observations.ResultsAccuracies of most GEBV for Angus and Brahman were between 0.1 and 0.4, with accuracies for abattoir carcass traits generally greater than for live animal body composition traits and reproduction traits. Estimated accuracies greater than 0.5 were only observed for Brahman abattoir carcass traits and for Angus carcass rib fat. Averaged across traits within breeds, accuracies of GEBV were highest when PE from the pooled across-breed training population were used. However, for the Angus and Brahman breeds the difference in accuracy from using pure-breed PE was small. For the Limousin breed no reasonable results could be achieved for any trait.ConclusionAlthough accuracies were generally low compared to published accuracies estimated within breeds, they are in line with those derived in other multi-breed populations. Thus PE developed by the Beef CRC can contribute to the implementation of genomic selection in Australian beef cattle breeding.

The great diversity of major histocompatibility complex class II genes in Philippine native cattle

Bovine leukocyte antigens (BoLA) are extensively used as markers for bovine disease and immunological traits. However, none of the BoLA genes in Southeast Asian breeds have been characterized by polymerase chain reaction (PCR)-sequence-based typing (SBT). Therefore, we sequenced exon 2 of the BoLA class II DRB3 gene from 1120 individual cows belonging to the Holstein, Sahiwal, Simbrah, Jersey, Brahman, and Philippine native breeds using PCR-SBT. Several cross-breeds were also examined. BoLA-DRB3 PCR-SBT identified 78 previously reported alleles and five novel alleles. The number of BoLA-DRB3 alleles identified in each breed from the Philippines was higher (71 in Philippine native cattle, 58 in Brahman, 46 in Holstein×Sahiwal, and 57 in Philippine native×Brahman) than that identified in breeds from other countries (e.g., 23 alleles in Japanese Black and 35 in Bolivian Yacumeño cattle). A phylogenetic tree based on the DA distance calculated from the BoLA-DRB3 allele frequency showed that Philippine native cattle from different Philippine islands are closely related, and all of them are closely similar to Philippine Brahman cattle but not to native Japanese and Latin American breeds. Furthermore, the BoLA-DRB3 allele frequency in Philippine native cattle from Luzon Island, located in the Northern Philippines was different from that in cattle from Iloilo, Bohol, and Leyte Islands, which are located in the Southern Philippines. Therefore, we conclude that Philippine native cattle can be divided into two populations, North and South areas. Moreover, a neutrality test revealed that Philippine native cattle from Leyte showed significantly greater genetic diversity, which may be maintained by balancing selection. This study shows that Asian breeds have high levels of BoLA-DRB3 polymorphism. This finding, especially the identification of five novel BoLA-DRB3 alleles, will be helpful for future SBT studies of BoLA-DRB3 alleles in East Asian cattle.

Pre- and postweaning calf performances in crossbred cattle from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams

<h2>ABSTRACT</h2> Growth traits were evaluated on 560 calves (288 male and 272 female calves) to determine the source and extent of tropical adaptation affecting calf pre-weaning and postweaning growth performances. Calves with Brangus dams were sired by Braford (BFBN; n=115; 38% Brahman), Hereford (HEBN; n=92; 19% Brahman), and Bonsmara (BOBN; n=139; 19% Brahman and 31% Africander) sires. Calves with Angus (AN) dams were sired by Hereford (HEAN; n=95) and Bonsmara (BOAN, n=119; 31% Africander) sires. Growth performances of BFBN and HEBN calves were similar (P>0.15) for an array of growth traits. However, BFBN and HEBN either tended to (P<0.10) or had (P<0.05) greater adjusted birth BW, postweaning ADG, and adjusted 452-d BW when compared with BOBN. Calves with AN dams and Bonsmara sires had greater preweaning ADG (P<0.05), adjusted 205-d BW (P<0.01), and adjusted 452-d BW (P<0.01) than HEAN calves. Among calves with Brangus dams, extent (BFBN vs. HEBN) of tropical adaptation was not important in terms of growth, but source (BFBN vs. BOBN and HEBN vs. BOBN) of tropical adaptation did not favor those calves with Africander breeding. However, for calves with AN dams, the use of Bonsmara sires (BOAN) imparted a growth advantage relative to the HE sires (HEAN). It is important that tropical adaptation, in terms of Brahman and Africander breeding, be imparted to the calf directly but more importantly, that Brahman breeding is imparted maternally.

Feedlot performance, carcass merit, and meat tenderness in crossbred cattle from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams

<h2>ABSTRACT</h2> The objective of this research was to evaluate the source and extent of tropical adaptation affecting feedlot and carcass traits. Calves of Brangus (BN) dams were sired by Braford (BFBN; n=63; 38% Brahman), Hereford (HEBN; n=38; 19% Brahman), and Bonsmara (BOBN; n=53; 19% Brahman and 31% Africander) sires. Calves of Angus (AN) dams were sired by Hereford (HEAN; n=38) and Bonsmara (BOAN; n=45; 31% Africander) sires. Carcass yield and LM area were greater (P<0.05) for HEBN compared with BFBN. Whereas BFBN had greater (P<0.01) backfat and empty body fat than the BOBN counterparts, the latter had greater (P<0.01) LM area. Contrasting HEBN and BOBN, HEBN were heavier (P<0.05) and fatter (P<0.05). However, BOBN were more heavily muscled (P<0.05) and deposited more internal fat (P<0.05). The BOAN steers were heavier (P<0.05) upon feedlot arrival than HEAN steers. Steers of Brangus (BN) dams were heavier (P<0.01), but steers of Angus (AN) dams exhibited greater (P<0.01) marbling scores. There were neither sire-breed nor dam-breed differences (P>0.15) in Warner-Bratzler shear force values. Presence of Brahman breeding (BN) in the dam breed positively affected weight traits, whereas absence of Brahman breeding (AN) positively affected carcass merit traits. In terms of sire breed contributions, neither extent nor source of tropical adaptation provided a distinct overall advantage in this study.

Multi-trait assessment of early-in-life female, male and genomic measures for use in genetic selection to improve female reproductive performance of Brahman cattle

Early-in-life female and male measures with potential to be practical genetic indicators were chosen from earlier analyses and examined together with genomic measures for multi-trait use to improve female reproduction of Brahman cattle. Combinations of measures were evaluated on the genetic gains expected from selection of sires and dams for each of age at puberty (AGECL, i.e. first observation of a corpus luteum), lactation anoestrous interval in 3-year-old cows (LAI), and lifetime annual weaning rate (LAWR, i.e. the weaning rate of cows based on the number of annual matings they experienced over six possible matings). Selection was on an index of comparable records for each combination. Selection intensities were less than theoretically possible but assumed a concerted selection effort was able to be made across the Brahman breed. The results suggested that substantial genetic gains could be possible but need to be confirmed in other data. The estimated increase in LAWR in 10 years, for combinations without or with genomic measures, ranged from 8 to 12 calves weaned per 100 cows from selection of sires, and from 12 to 15 calves weaned per 100 cows from selection of sires and dams. Corresponding reductions in LAI were 60–103 days or 94–136 days, and those for AGECL were 95–125 or 141–176 days, respectively. Coat score (a measure of the sleekness or wooliness of the coat) and hip height in females, and preputial eversion and liveweight in males, were measures that may warrant wider recording for Brahman female reproduction genetic evaluation. Pregnancy-test outcomes from Matings 1 and 2 also should be recorded. Percentage normal sperm may be important to record for reducing LAI and scrotal size and serum insulin-like growth factor-I concentration in heifers at 18 months for reducing AGECL. Use of a genomic estimated breeding value (EBV) in combination with other measures added to genetic gains, especially at genomic EBV accuracies of 40%. Accuracies of genomic EBVs needed to approach 60% for the genomic EBV to be the most important contributor to gains in the combinations of measures studied.

Selection of Brahman crossbred-breeding bulls based on phenotypic performance

A beef breed development project was carried out in the Department of Livestock Services (DLS) in 2009 in selected areas of Bangladesh. Under this project, semen of Brahman bulls were imported from the USA and used to inseminate indigenous cows to produce graded calves. The present study was undertaken to select graded Brahman bulls of the aforesaid project for breeding purpose. Using the data of Brahman grade-1 population, 4 (four) bulls were selected based on external appearance, phenotypic performance and libido. Records on 233 Brahman grade-1 calves (127 male and 106 female) were analyzed by SAS computer program. Birth weight, yearling weight and average daily gain were estimated by considering sex and area groups. The birth weight was found to be 22.25±5.60 Kg for male and 20.33±3.88 Kg for female calves (average 21.38±4.98 Kg). The yearling weight of male and female calves was found to be 222.07±73.21 and 191.76±69.04 Kg, respectively. Highest yearling weight and average daily gain were found in Charghat (401.11±39.75 kg and 1034.82±107.90 g, respectively) while lowest values were in Thakurgaon area (152.69±52.74 Kg 369.42±141.94 g, respectively). The average daily gain male and female calves were 547.42±193.7 and 470.34±184.52 g, respectively. Area and sex had highly significant (p&lt;0.001) effects on birth weight, yearling weight and average daily gain of calves. The average daily gain of four selected graded Brahman bull calves was 731 g. The estimated selection differential and selection intensity for average daily gain of the four bulls were 183.53 g and 2.263, respectively. The growth performance along with estimated selection intensity and selection differential for average daily gain indicated that these selected graded Brahman breeding bulls may generate a good opportunity to improve indigenous cattle for beef purposes.DOI: http://dx.doi.org/10.3329/bjas.v41i2.14101Bang. J. Anim. Sci. 2012. 41 (2): 60-66

Evaluation of tropically adapted straightbred and crossbred cattle: Postweaning BW gain and feed efficiency when finished in a temperate climate1,2

Beef cows in the subtropical USA must be adapted to the stressors of the environment, typically supplied by using Brahman (Br) breeding. Calves produced in the region, however, are usually grown and finished in more temperate regions, and have a perceived reputation for poor ADG and feed efficiency during finishing. Compromised fertility and carcass quality often associated with the Br have increased interest in tropically adapted Bos taurus breed types. The objective of this study was to evaluate 3 breeds [An = Angus (Bos taurus, temperate); Br (B. indicus, tropical); and Ro = Romosinuano (B. taurus, tropical)] and all possible crosses during various segments of post-weaning growth, and for feed efficiency during the finishing phase. Steer calves (n = 473) born over 3 yr were weaned in late September, backgrounded for at least 21 d (BKG), shipped 2,025 km to El Reno, OK, in October, fed a preconditioning diet for 28 d (RCV), grazed wheat (Triticum aestivum L.) pasture from November to May (WHT), finished on a conventional feedlot diet (FIN), and serially harvested after approximately 95, 125, and 150 d on feed. Body weight and ADG during each segment were tested using a mixed model that included calf age at weaning, year (Y), breed of sire (SB), breed of dam (DB), and interactions. In addition, winter treatment (continuous wheat or reduced grazing of wheat with supplement) was included for the wheat and feedlot phases. Sire within SB × SB [and pen (barn × year) for feedlot phase] were considered random. The SB × DB interaction was significant for all traits (P < 0.01) except exit velocity taken at weaning and ADG during FIN, but both traits were affected by 3-way interactions with Y or harvest group. Tropically-adapted purebred steers had greater (P < 0.01) ADG than AnAn through weaning and BKG in FL but the reverse was true during the RCV and WHT segments. Similar, but less pronounced results were noted for F(1) steers with 100% tropical influence compared with those with only 50%. Heterosis was numerically greater for most traits for An × Br (11 to 64%) compared with An × Ro and Br × Ro (3 to 42%), which were similar. In a subset of the steers (n = 261), G:F was not influenced by level of tropical breeding, but tropically adapted steers were more efficient (P < 0.05) by residual feed intake. No heterosis was evident. These data show that in temperate zones, winter is the period when productivity of tropically adapted cattle is compromised.

Genome-wide association studies of female reproduction in tropically adapted beef cattle1

The genetics of reproduction is poorly understood because the heritabilities of traits currently recorded are low. To elucidate the genetics underlying reproduction in beef cattle, we performed a genome-wide association study using the bovine SNP50 chip in 2 tropically adapted beef cattle breeds, Brahman and Tropical Composite. Here we present the results for 3 female reproduction traits: 1) age at puberty, defined as age in days at first observed corpus luteum (CL) after frequent ovarian ultrasound scans (AGECL); 2) the postpartum anestrous interval, measured as the number of days from calving to first ovulation postpartum (first rebreeding interval, PPAI); and 3) the occurrence of the first postpartum ovulation before weaning in the first rebreeding period (PW), defined from PPAI. In addition, correlated traits such as BW, height, serum IGF1 concentration, condition score, and fatness were also examined. In the Brahman and Tropical Composite cattle, 169 [false positive rate (FPR) = 0.262] and 84 (FPR = 0.581) SNP, respectively, were significant (P < 0.001) for AGECL. In Brahman, 41% of these significant markers mapped to a single chromosomal region on BTA14. In Tropical Composites, 16% of these significant markers were located on BTA5. For PPAI, 66 (FPR = 0.67) and 113 (FPR = 0.432) SNP were significant (P < 0.001) in Brahman and Tropical Composite, respectively, whereas for PW, 68 (FPR = 0.64) and 113 (FPR = 0.432) SNP were significant (P < 0.01). In Tropical Composites, the largest concentration of PPAI markers were located on BTA5 [19% (PPAI) and 23% (PW)], and BTA16 [17% (PPAI) and 18% (PW)]. In Brahman cattle, the largest concentration of markers for postpartum anestrus was located on BTA3 (14% for PPAI and PW) and BTA14 (17% PPAI). Very few of the significant markers for female reproduction traits for the Brahman and Tropical Composite breeds were located in the same chromosomal regions. However, fatness and BW traits as well as serum IGF1 concentration were found to be associated with similar genome regions within and between breeds. Clusters of SNP associated with multiple traits were located on BTA14 in Brahman and BTA5 in Tropical Composites.

Effects of physiological age on residual feed intake of growing heifers

Using a retrospective evaluation of feed efficiency, this study investigated the effects of physiological age on residual feed intake (RFI) in growing heifers. Data were collected during 1973 and 1974 at the McGregor location of the Texas Agricultural Experiment Station. Heifers (n = 77) were obtained from a large crossbreeding program utilizing a five-breed diallel mating scheme using Angus, Brahman, Hereford, Holstein and Jersey breeds. At approximately 6 months of age, pre-pubertal heifers were individually penned and received ad libitum access to a balanced diet. Individual feed intake and body weight data were collected at 28-day intervals for 84 days prior to puberty and for 90 days after puberty. The diet was changed at puberty to provide a lower energy density. Considering all females as cohorts, RFI was calculated for each heifer for each period using separate models for the pre- and post-pubertal periods. A moderate, positive Pearson correlation (r = 0.48; P < 0.001) was detected between pre- and post-pubertal RFI. Furthermore, heifer RFI rank was compared between the pre- and post-pubertal periods using Spearman rank order correlation and a similar correlation (r = 0.46; P < 0.001) was revealed. This suggests that RFI determined during the pre-pubertal period may only be a moderate predictor of post-pubertal RFI. As a result, physiological age should be considered when evaluating cattle for feed efficiency using RFI.

Tenderness and intramuscular lipid of most major muscles from Bos indicus cattle are less than Bos taurus cattle

Introduction In semitropical climates in the United States, Bos indicus breeds of cattle, primarily the Brahman breed, are utilized in crossbreeding programs with Bos taurus cattle to improve productivity by increasing disease and insect resistance, heat tolerance, heterosis, and additive genetic variation. About 25% of the U.S. beef population contains some Bos indicus breeding. Numerous published reports show that tenderness of ribeye and strip loin steaks and marbling are significantly reduced in Bos indicus straightbred or crossbred cattle compared to most Bos taurus breeds. One very large study reported that heritability of tenderness and marbling is around 0.4, making it a positive trait to try to improve through selection. Only one published report has compared tenderness differences between Bos indicus and Bos taurus cattle for more than the ribeye and strip loin (longissimus muscle) and that study showed that other muscles were less tender for Bos indicus cattle. The objectives of our study were: (1) to compare carcass traits between Hereford x Angus crossbred cattle with those containing at least 50% Brahman and Sahiwal inheritance, and (2) to validate Warner-Bratzler shear force of steaks and roasts and proximate composition of 10 different muscles from these cattle.

143 TREATMENT WITH VITAMINS A AND E IMPROVE OOCYTE QUALITY AND IN VITRO EMBRYO DEVELOPMENT IN BOS INDICUS COWS

We assessed the impact of a single intra-muscular injection of vitamins A and E on oocyte quality and yield and early embryo development in Bos indicus cows. Twenty Bos indicus cows, of Gyr, Brahman, and Nellore breeds, weighing between 450 and 600 kg were subjected to ovum pick-up (OPU). Oocytes were collected in Dulbecco’s PBS (DBPS) containing heparin and antibiotics, counted, and morphologically classified. Viable oocytes were taken to the laboratory, in vitro matured for 24 h and in vitro fertilized using 25 million sperm mL–1. After 168 h of incubation (39°C, 5% CO2), viable embryos were counted and classified. Then, after 10 days, the cows received an intra-muscular injection of 1 000 000 UI of vitamin A and 1 g of vitamin E, and, after 12 days, were again subjected to the same procedure described above. Differences in oocyte yield and embryo development were analysed using paired t-test. The 40 OPUs from 20 cows yielded a total of 520 oocytes. Nellore and Brahman cows produced more embryos/cow (P &lt; 0.01) compared with Gyr. After vitamin treatment, the cows produced more oocytes (n = 303; P &lt; 0.01) compared with the previous OPU (n = 217), resulting in 95 more viable oocytes (31%). Brahman, Gyr, and Nellore cows yielded 11.2 ± 1.8, 8.5 ± 1.5, and 12.0 ± 2.6 oocytes before vitamin treatment, respectively. From those oocytes, 224 embryos were obtained, 89 before vitamin injection and 135 after treatment (P &lt; 0.02), with 36 more embryos (40%) produced. Irrespective of breed, cows responded equally to vitamin injection. A single parenteral injection of vitamins A and E had a significant positive effect on oocyte yield after OPU and in vitro embryo development on Bos indicus cows. We suggest that this effect is probably due to the positive influence of retinoids on oocyte and embryo development.

Population genetic analysis of the Brahman cattle (Bos indicus) in Colombia with microsatellite markers

The Brahman is one of the most popular breeds for meat production in the Neotropics. However, genetic studies of the breed in Latin American countries have only recently begun. In total, 178 animals of the Brahman breed from 20 Colombian provinces were genotyped at 11 microsatellite markers with the aim of studying the genetic diversity of this population and its genetic relationships with zebuine and taurine breeds. The outcomes of multivariate analyses, Bayesian inferences and inter-individual genetic distances suggested that there is no genetic sub-structure in the population, because of the high rate of animal migration among provinces. The population shows a high degree of heterozygosity and allelic diversity compared with other breeds, reflecting its multibreed origin. The study of the genetic relationships among the breeds reveals that the Brahman breed belongs to the zebuine group. However, it is the population nearest to taurine breeds with high frequencies of taurine alleles. Intensive artificial selection may have favoured the taurine alleles after the breed was formed. There has also been some degree of mixture with local taurine breeds while the Brahman breed has evolved in Colombia.

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.

The effect of variation at the retinoic acid receptor-related orphan receptor C gene on intramuscular fat percent and marbling score in Australian cattle1,2

Variation at the retinoic acid receptor-related orphan receptor C (RORC) gene was previously associated with marbling score in a large sample of Australian taurine feedlot cattle of Angus and Shorthorn breeds. The T allele at the SNP RORC:g.3290T > G increased marbling score in Angus and Shorthorn cattle. We genotyped this SNP in an independent sample of 2,741 Australian cattle of Angus, Brahman, and Hereford breeds, and tested the association of this SNP with marbling score in all animals and with intramuscular fat (IMF) measurements in 2,104 animals. We found an allele frequency of the G allele of p(G) = 0.57 in Angus, p(G) = 0.09 in Hereford, and p(G) = 0.64 in Brahman. The regression of marbling score against number of copies of the G allele was significant (P = 0.033) in the combined sample after accounting for ancestry, breed, and the contemporary group structure of the data. All breeds had the same favorable homozygote; the regression on alleles showed a trend in Angus and Brahman cattle (P < 0.1), but not in Hereford cattle (P = 0.912). The regression of IMF against number of copies of the G allele was significant (P = 0.018) after accounting for ancestry, breed, and contemporary group structure. All breeds had the same favorable homozygote and the regression on alleles was significant (P = 0.024) in the Angus breed. In all breeds tested in this study, the T allele increased both marbling score and IMF. This polymorphism explained 0.3% of the phenotypic variance for IMF in this sample.

Structural and Functional Analysis of the BovineMx1Promoter

The bovine Mx1 promoter region was found to contain 4 IFN-stimulated response elements (ISREs), 7 GC boxes, 2 IL-6 responsive elements, 2 NFκB-binding sites and 2 AP-1-binding sites. Among Holstein, Charolai, and Brahman breeds, 5 nucleotide substitutions were detected in the promoter region. After the Mx1 promoter region from Holstein had been constructed with pGL-basic expression vector, the transfected cells showed promoter activity after IFN induction. Several artificial deletion mutants were prepared to determine the important regulatory elements responsible for the promoter activity, and it was found that ISRE has a key function in IFN response. The proximal ISRE1 showed potential induction by IFN. Furthermore, the proximal GC boxes were found to be essential for IFN response in the bovine Mx1 promoter with the deletion mutants. In this case, the 2 GC boxes exhibited a synergistic activation in the IFN response. Mithramycin A, an agent that inhibits gene expression selectively by coating GC boxes, was used, and Mx mRNA expression in MDBK cells was suppressed by this chemical. Therefore, GC boxes were also shown to be essential for IFN response in the bovine Mx1 gene.

Effect of two dietary concentrate levels on tenderness, calpain and calpastatin activities, and carcass merit in Waguli and Brahman steers1

The objective of this study was to compare carcass characteristics of a newly introduced breed, the Waguli (Wagyu x Tuli), with the carcass characteristics of the Brahman breed. Brahman cattle are used extensively in the Southwest of the United States because of their tolerance to adverse environmental conditions. However, Brahman carcasses are discounted according to the height of their humps because of meat tenderness issues. The Waguli was developed in an attempt to obtain a breed that retained the heat tolerance of the Brahman but had meat quality attributes similar to the Wagyu. Twenty-four animals were used. Six steers from each breed were fed a 94% concentrate diet and 6 steers from each breed were fed an 86% concentrate diet. Eight steers, 2 from each group, were harvested after 128 d, after 142 d, and after 156 d on feed. Waguli steers had larger LM, greater backfat thickness, greater marbling scores, and greater quality grades than the Brahman steers (P < 0.05). The Japanese Wagyu breed is well known for its highly marbled and tender meat, and these traits are also present in the Waguli. The Waguli had significantly lower Warner-Bratzler shear force values than the Brahman steers after 7 and 10 d of postmortem aging (P < 0.05); this difference decreased after 14 d postmortem (P = 0.2), when tenderness of the slower aging Brahman had increased to acceptable levels. Toughness of the Brahman has been associated with high levels of calpastatin in Brahman muscle, and the Waguli LM had significantly less calpastatin activity (P = 0.02) at 0 h postmortem than the Brahman LM. At 0-h postmortem, the total LM calpain activity did not differ between the Brahman and Waguli (P = 0.57). Neither diet nor days on feed had any significant effect on the 0-h postmortem calpain or at 0-h postmortem calpastatin activity, nor an effect on Warner-Bratzler shear-force values. In conclusion, LM muscle from the Waguli steers had a high degree of marbling, lower shear force values, and low calpastatin activity, all of which are related to more tender meat.

A simplified method for cholesterol determination in meat and meat products

The objectives of this study were to develop an accurate and precise method for cholesterol quantification in meat samples based on modifications made to an existing procedure (AOAC Official Method 994.10), and to apply this modified method to evaluate cholesterol levels in longissimus muscles (LM) from Angus (AN, n=5), Brahman (BR, n=4), and Romosinuano (RM, n=9) breeds. Validation of this method was performed using a meat homogenate (Standard Reference Material 1546) from National Institute of Standards and Technology (NIST), and LM samples from the three breeds with fat contents ranging from 2.4% to 9.3%. The results indicated that the modified method was accurate with cholesterol recovery exceeding 95%. The method was also found to be precise with an average coefficient of variation of 3.12%. The modification reduced 90% of chemicals used and eliminated time-consuming steps that hindered high throughput application of the traditional method. The application of this method to quantify cholesterol contents of LM samples revealed differences among the three breeds evaluated. The Angus LM with a higher fat content (50% higher) was associated with a significantly higher cholesterol concentration (70.25 mg/100 g) as compared to LM from Brahman and Romosinuano purebreds (64.77 and 65.76 mg/100 g; P=0.005 and 0.006, respectively). Cholesterol concentration was found to be correlated with the i.m. fat content of LM muscle from the three breeds ( r=0.90, P<0.001). Cholesterol concentrations of LM determined in this study were comparable to those reported in the USDA National Nutrient Database for Standard Reference for separable lean from Choice rib-eye steaks. This modified method was reliable and should be evaluated for adoption as an appropriate method for cholesterol quantification in meat samples.

Genetic diversity among Angus, American Brahman, Senepol and Romosinuano cattle breeds

The objective of this study was to quantify the genetic diversity among breeds under evaluation for tropical adaptability traits that affect the performance of beef cattle at the USDA/ARS SubTropical Agricultural Research Station (STARS) near Brooksville, FL, USA. Twenty-six microsatellite loci were used to estimate parameters of genetic diversity among the breeds American Brahman, Angus, Senepol and Romosinuano; the latter was comprised of two distinct bloodlines (Costa Rican and Venezuelan). Genotypes of 47 animals from each of these STARS herds were analysed for genetic diversity and genetic distance. Using two methods, the greatest genetic distance was detected between the Costa Rican line of Romosinuano and the Senepol. Gene diversity ranged between 0.64 (Costa Rican line of Romosinuano) and 0.75 (American Brahman). The breed relationship inferences, which are based on genetic distance, provide additional tools for consideration in future crossbreeding studies and for testing the relationship between quantified breed diversity and observed heterosis.

196 COMPARING OOCYTE LIPID CONTENT WITH CIRCULATING CHOLESTEROL AND TRIGLYCERIDE LEVELS OF BOS TAURUS AND BOS INDICUS DONOR COWS

Intracellular lipid content has been found to be higher in Bos indicus oocytes compared with Bos taurus oocytes (Ballard et al. 2007 Reprod. Fertil. Dev. 19, 170). The objective of this study was to further determine whether there was a correlation between oocyte lipid content and circulating cholesterol (CHL) and triglyceride (TRG) levels of mature purebred Brahman (BR; n = 11) and English breed (EN; n = 13) beef cows. All donor cows were maintained on the same ration 30 days prior to and during the oocyte collection interval. Oocytes were collected from donors at 30-day intervals (3 replicates/female) by transvaginal ultrasound-guided aspirations. Blood samples were collected to evaluate total circulating CHL and TRG levels just prior to CIDR insertion and again prior to oocyte collection. Follicle-stimulating hormone (Folltropin-V; Bioniche, Belleville, Ontario, Canada) was given twice daily for 3 days in decreasing doses beginning on Day 4 after CIDR insertion, with oocyte recovery on Day 8. The mean number of follicles aspirated/donor and oocytes recovered/donor were 12 and 11 for the BR and 18 and 7 for the EN donors, respectively. Oocytes were matured in TCM-199 with 10% fetal bovine serum + bovine LH and bovine FSH (0.01 U mL–1). After 20 h, mature oocytes with a visible polar body (BR = 242/391 or 61%, and EN = 170/258 or 65%) were denuded by vortexing in Tyrodes HEPES medium + BSA (0.03 mg mL–1). Visual color scores (1 = light, 2 = medium, 3 = dark) were then assigned to the oocytes. Buoyancy of mature oocytes was then measured by using a sucrose step-density gradient column prepared with sucrose and Dulbecco's PBS. Results from the sucrose gradients ranged from 23% (high lipids) to 35% (lower lipids). The oocytes were stained with Nile Red and evaluated by fluorescent microscopy. Oocyte images were evaluated by using Scion Image software to calculate the Nile Red units (NRU; higher NRU = higher lipid content). Serum was analyzed (Texas Veterinary Medical Diagnostic Laboratory) for CHL and TRG concentrations. Data were analyzed by one-way ANOVA. There was no difference between visual color scores for oocytes from BR and EN donors. However, BR oocytes had significantly (P &lt; 0.05) lower buoyant density and significantly higher mean NRU scores (32% and 173) compared with oocytes harvested from EN donors (33% and 152), respectively. Serum CHL and TRG levels were both significantly higher (P &lt; 0.05) in the BR donors (150 and 33.2) compared with the EN donors (110 and 25.5), respectively. These results suggest that serum cholesterol and triglyceride levels may be predictive of donor oocyte lipid content.

Genetic Characterization of Argentine and Bolivian Creole Cattle Breeds Assessed through Microsatellites

In the present report, the polymorphisms from 9 microsatellites were used to assess genetic diversity and relationships in 4 Creole cattle breeds from Argentina and Bolivia, 4 European taurine breeds, and 2 American zebu populations. The Creole populations display a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity, whereas the British breeds displayed reduced levels of genetic diversity. The analysis of molecular variance indicated that 7.8% of variance can be explained by differences among taurine and zebu breeds. Consistent with these results, the first principal component (PC), which comprised the 40% of the total variance, clearly distinguishes these 2 groups. In addition, all constructed phylogenetic trees cluster together Nelore and Brahman breeds with robust bootstrap values. Only 1% of variance was due to difference between American Creole and European taurine cattle. Although this secondary split was supported by the classical genetic distance and the second PC (15%), the topology of trees is not particularly robust. The presence of zebu-specific alleles in Creole cattle allowed estimating a moderate degree of zebu admixture. When these data were compared with mitochondrial and Y chromosomal studies, a clear pattern of male-mediated introgression was revealed. The results presented here contribute to the understanding of origin and history of the American Creole cattle.