Development of genomic predictions for Angus cattle in Brazil incorporating genotypes from related American sires

Genomic prediction has become the new standard for genetic improvement programs, and currently, there is a desire to implement this technology for the evaluation of Angus cattle in Brazil. Thus, the main objective of this study was to assess the feasibility of evaluating young Brazilian Angus (BA) bulls and heifers for 12 routinely recorded traits using single-step genomic BLUP (ssGBLUP) with and without genotypes from American Angus (AA) sires. The second objective was to obtain estimates of effective population size (Ne) and linkage disequilibrium (LD) in the Brazilian Angus population. The dataset contained phenotypic information for up to 277,661 animals belonging to the Promebo® breeding program, pedigree for 362,900, of which 1,386 were genotyped for 50k, 77k, and 150k SNP panels. After imputation and quality control, 61,666 SNP were available for the analyses. In addition, genotypes from 332 American Angus (AA) sires widely used in Brazil were retrieved from the AA Association database to be used for genomic predictions. Bivariate animal models were used to estimate variance components, traditional EBV, and genomic EBV (GEBV). Validation was carried out with the linear regression method (LR) using young-genotyped animals born between 2013 and 2015 without phenotypes in the reduced dataset and with records in the complete dataset. Validation animals were further split into progeny of BA and AA sires to evaluate if their progenies would benefit by including genotypes from AA sires. The Ne was 254 based on pedigree and 197 based on LD, and the average LD (±SD) and distance between adjacent SNPs across all chromosomes was 0.27 (±0.27) and 40743.68 bp, respectively. Prediction accuracies with ssGBLUP outperformed BLUP for all traits, improving accuracies by, on average, 16% for BA young bulls and heifers. The GEBV prediction accuracies ranged from 0.37 (total maternal for weaning weight and tick count) to 0.54 (yearling precocity) across all traits, and dispersion (LR coefficients) fluctuated between 0.92 and 1.06. Inclusion of genotyped sires from the AA improved GEBV accuracies by 2%, on average, compared to using only the BA reference population. Our study indicated that genomic information could help to improve GEBV accuracies and hence genetic progress in the Brazilian Angus population. The inclusion of genotypes from American Angus sires heavily used in Brazil just marginally increased the GEBV accuracies for selection candidates.

Haplotype-Based Single-Step GWAS for Yearling Temperament in American Angus Cattle

Behavior is a complex trait and, therefore, understanding its genetic architecture is paramount for the development of effective breeding strategies. The objective of this study was to perform traditional and weighted single-step genome-wide association studies (ssGWAS and WssGWAS, respectively) for yearling temperament (YT) in North American Angus cattle using haplotypes. Approximately 266 K YT records and 70 K animals genotyped using a 50 K single nucleotide polymorphism (SNP) panel were used. Linkage disequilibrium thresholds (LD) of 0.15, 0.50, and 0.80 were used to create the haploblocks, and the inclusion of non-LD-clustered SNPs (NCSNP) with the haplotypes in the genomic models was also evaluated. WssGWAS did not perform better than ssGWAS. Cattle YT was found to be a highly polygenic trait, with genes and QTL broadly distributed across the whole genome. Association studies using LD-based haplotypes should include NCSNPs and different LD thresholds to increase the likelihood of finding the relevant genomic regions affecting the trait of interest. The main candidate genes identified, i.e., ATXN10, ADAM10, VAX2, ATP6V1B1, CRISPLD1, CAPRIN1, FA2H, SPEF2, PLXNA1, and CACNA2D3, are involved in important biological processes and metabolic pathways related to behavioral traits, social interactions, and aggressiveness in cattle. Future studies should further investigate the role of these genes.

Study on the temperament of cows of the Aberdeen Angus cattle breed

The present study examined the temperament of 699 cows of the Aberdeen Angus cattle breed, reared in 14 farms in Bulgaria. It was carried out within the period 2017–2020. The animals subject to the study were between two and eight years old. The temperament was visually evaluated following a scoring system from 1 to 5. The assessment method involved the behavioural reaction of the cows upon manipulation, passing through a chute and fixation into a cattle crush. The temperament of cows reared in two different systems – intensive and semi-intensive farming was compared. The temperament of the Aberdeen Angus cows had an average rate of 2.74 ± 0.04. The cows which had frequent contact with people had a calmer temperament. The manner of rearing (P < 0.001) as well as the age group (P < 0.001) had a significant influence on the parameter examined. The young animals were calmer and got accustomed to working in a crush more easily when they were reared together with cows of different ages.

Composition of Fecal Microbiota in Grazing and Feedlot Angus Beef Cattle

This study is to investigate the difference in bovine fecal microbiota between grazing and feedlot Angus cattle. Fecal samples were collected from six Angus cattle grazed on grassland and six Angus cattle fed on a feedlot. The fecal bacterial community was analyzed by high-throughput sequencing of 16S rRNA gene. Sequencing of the V3–V4 region totally produced 1,113,170 effective tages that were computationally clustered into 775 operational taxonomic units (OTUs). These 775 OTUs were taxonomically assigned to bacterial 12 phyla, 19 classes, 25 orders, 54 families, 141 genera, and 145 species. The dominant phyla were Firmicutes and Bacteroidetes. There was similar species richness between grazing and feedlot Angus beef, while higher species diversity was observed in feedlot Angus beef. The relative abundance of Firmicutes, Cyanobacteria, Elusimicrobia and Patescibacteria was significantly different between grazing and feedlot Angus beef (p < 0.05). At a genus level, five microbiotas were significantly different between the two groups and all belonged to the Firmicutes phylum. These significant differences in microbiota composition between grazing and feedlot Angus beef may have an impact on the meat quality of Angus beef.

PSI-B-26 Association of leptin gene polymorphisms (C73T and C528T) on the development of internal organs in Aberdeen-angus cattle

Numerous studies have established the relationship of SNPs in the leptin gene with fat and energy exchange, nutritional behavior in cattle. In turn, the intensity of metabolic processes in body is determined by the development of internal organs. The purpose of research was to study the relationship between the complex of polymorphisms C73T and C528T in leptin gene for the formation of internal organs in Aberdeen-Angus cows and heifers. Cows (n = 30) and heifers (n = 49) were genotyped and identified respectively 7 and 8 various combinations of genotypes of C73T (GenBank AF120500) and C528T (GenBank AB070368). There were no homozygous CC/CC and TT/TT combinations in cows, and no TT/TT combination in heifers. Cows were slaughtered at the age of 3 years, and heifers - at 20 months. Cows with haplotype CT/CC had the highest liver, heart, lung, kidney and spleen weight with superiority relative to peers of 6.5–16.0% (P &gt; 0.05). The minimum development of stomachs was established at cows with a combination of genotypes of CC/TT which conceded to analogs for 7.6–13.8% (P &gt; 0.05). Haplotypes CT/CT and TT/CT in heifers were associated with greater internal organ massiveness. Carriers of complex CT/CT genotype outperformed peers in terms of liver, heart, lung, kidney and spleen weight by 1.75–6.59% (P &lt; 0.05, P &gt; 0.05), and individuals with a combination of TT/CT by 3.50–8.84% (P &lt; 0.05, P &gt; 0.05). Less developed stomachs were established in bodies with haplotype TT/CC, which were inferior to other genotypes by 1.20–7.49% (P &lt; 0.05, P &gt; 0.05). This indirectly indicates a relatively weak ability to use coarse plant foods. Thus, the complex genotype inleptin gene is associated with the variability in the development of internal organs, which determines the intensity of metabolic processes. This research was performed with financial support from the project of RAS0526-2021-0001.

PSVIII-4 Genetic evaluation of functional heifer longevity in north American angus cattle

The goals of this study were to develop a genetic evaluation system for a novel trait called functional heifer longevity (FHL), and determine if this novel trait is heritable. The FHL trait was defined as binary, in which the heifers received the code 1 if they had calved by the end of their third year (n = 377,938), or 0 if they were culled/sold during this period (n = 368,308). Analysis were performed using linear animal models and Bayesian inference. The significant systematic effects included in the statistical models are born by embryo transfer, year-season of birth, and age at calving (in months). Three models, differing according to their random effects (i.e., reduced model, which included only herd-year-season and additive genetic random effects; maternal genetic model, which added maternal genetic effects; and complete model, which further added maternal permanent environmental effects), were compared based on the deviance information criterion (DIC) and the estimates of genetic parameters. The reduced model was preferred according to the DIC values. However, high maternal heritabilities were estimated using the maternal genetic (0.51) and complete (0.36) models, indicating that maternal effects can impact the selection of heifers for breeding. Similar additive genetic heritabilities were estimated among the three models (0.24, 0.27, and 0.25 using the reduced, maternal genetic, and complete models, respectively), and no significant re-ranking of selection candidates were observed based on their additive genetic breeding values. Total heritabilities and correlations estimated between additive genetic and maternal genetic effects were 0.37 and -0.28 for the maternal genetic, and 0.31 and -0.27 for the complete model, respectively. This study shows that FHL is heritable, and that including maternal effects in the statistical models might be important. These results contribute to a larger project studying the genetics of female longevity in Angus cattle.

PSXV-3 The influence of the dams genotype on the indicators of the breeding value of offspring

Aberdeen Angus cattle of Australian breeding is a new ecological and genetic genotype and it is currently in the process of formation and differentiation, the genealogy of the breeding stock is represented by the leading related groups of bulls-leaders of domestic and imported breeding. The aim of this work was to study the breeding value of Bismarck5682bovine cows of Australian selection (n = 20) and Design1015 (n = 20) of domestic reproduction of the Aberdeen-Angus breeding and their influence on the selection and genetic parameters of the productivity of heifers-daughters. It was revealed that the representatives of the Design line had an advantage in live weight (615.4 kg,lim-705-495kg) by 9.8% (P &lt; 0.001), milk productivity (219.7 kg,lim-241-184kg) by 2.4% (P &gt; 0.05) and height insacrum (134.5 cm,lim-140cm-128cm) by 4.1% (P &lt; 0.001) compared to peers of Bismarck line.The ability of animals to realize their breeding potential is determined by many factors. So, it was revealed that the heifers of Design lineexceeded their peers from Bismarck group in live weight in 15 months (359.8 kg, Cv-5.24%) by 5.2%, (P &gt;0.05), average daily gain (652.8 g, Cv-7.86%) - 10.6% (P&lt; 0.001), body conformation score (19.7 points, Cv-3.72)- 14.5% (P&lt; 0.01). It should be noted that heifers – daughters of the Bismarck genealogical line gave in sacrum height but had a better estimate of meat forms by 2.9% with reliable values. These results allow us to conclude that the offspring of the Bismarck 5682 genealogical line of Australian breeding are more affected by the negative factors of the new breeding zone. Thus, a step-by-step selection evaluation of the breeding stock will allow more reliable identification of breeding bulls with a better ability to improve valuable distinguishing features in the generations of cows during their linear breeding. The research was carried out within the framework of RAS 0526-2021-0001.

PSIX-4 Comparison of water footprint in roughage-fed and grain-fed beef cattle finishing systems

Beef cattle production has been argued to represent a massive player on water usage given the high-water footprint (WF) attributed to the livestock sector. From a water usage mitigation standpoint, at the animal level, manipulation of drinkable water is possible since major differences in water utilization are highly related to diet composition and feed quality. The objective of this study was to evaluate the effects of two cattle finishing systems, grain-finished versus roughage-finished on dry matter intake (DMI), water intake (WI), WF and water use efficiency (WUE) of Angus cattle. Twenty-four steers (385 ± 10.80 kg) were fed either alfalfa only (roughage-finished) or predominantly whole grain (80% corn and 20% alfalfa). Individual DMI and WI were measured for 105 days. Water footprint was expressed as amount of green (rainwater; WFg), blue (surface and groundwater; WFb), and grey (waste; WFgy) water used for feed production and WI of animals, and the sum of all three represents the total WF (TWF). The WUE was calculated as the integral between water used during the experimental period, and then converted into water efficiency as divided by cold carcass weight (CCW). Differences amongst treatments were compared via orthogonal contrast using the GLIMMIX procedure of SAS (version 9.4) with treatment as fixed effect and animals as a random effect. Roughage-fed animals presented significantly higher WI and DMI (P = 0.0005 and P &lt; 0.0001, respectively), 80 kg lighter CCW (P = 0.0005) when compared to grain-finished animals. Grain-finished animals had a lower WFb WFgy, and TWF (P &lt; 0.0001), but a higher WFg (P &lt; 0.0001). Water use efficiency was twice as high for roughage-fed animals. Therefore, for the finishing phase, steers finished on a grains had a lower WF when compared to roughage-fed animals.

35 Detecting Effective Starting Point of Genomic Selection by Divergent Trends from BLUP and ssGBLUP

Genomic selection has been adopted nationally and internationally in different livestock and plant species. However, understanding whether genomic selection has been effective or not is an essential question for both industry and academia. Once genomic evaluation started being used, estimation of breeding values with pedigree BLUP became biased because this method does not consider selection using genomic information. Hence, the point of divergence of genetic trends obtained with BLUP and Single-step genomic BLUP (ssGBLUP) may indicate the start date of genomic selection. This study aimed to find the start date of genomic selection for a set of economically important traits in pigs and Angus cattle by comparing genetic and Realized Mendelian sampling (RMS) trends obtained using BLUP and ssGBLUP. In pigs, the genetic trends from ssGBLUP and BLUP diverged for all traits with different intensity. In beef cattle, the trends started diverging in 2009 for weaning weight and in 2016 for postweaning gain, with little divergence for birth weight. In pigs, the RMS trends from ssGBLUP and BLUP diverged strongly for one trait and weakly for another trait. In beef cattle, the RMS trends started diverging in 2009 for weaning weight and in 2016 for postweaning gain, with little trend for birth weight. Divergence of the genetic trends from ssGBLUP and BLUP indicate onset of the genomic selection. Presence of trends for RMS indicates selective genotyping, with or without the genomic selection. The onset of genomic selection and genotyping strategies agree with industry practices across the two species. In summary, the effective start of genomic selection can be detected by the divergence between genetic and RMS trends from BLUP and ssGBLUP.

PSVI-15 Combined effect of C73T × C528T polymorphisms in the leptin gene with quantitative and qualitative indicators of meat productivity

The LEP is a highly polymorphicgene and it is associated with genetic differences in various productivetraits in cattle. The aim of research was to study the combined effect of C73T and C528T polymorphisms in leptin gene on meat productivity and carcass grade in Aberdeen-Angus cows and heifers. Heifers (n = 49) were slaughtered at the age of 20 months and cows (n = 30) after the first calving (3 years). There were seven haplotypes C73T (GenBank AF120500) × C528T (GenBank AB070368) identified in cows with different frequency. The maximum frequency was established in combined genotypes CT/CT (0.37), TT/CC (0.27) and CT/CC (0.13). The most massive carcasses (337.5 kg) were obtained from cows-carriers of the CT/CC haplotype, which exceeded their peers by 14.8–24.7 kg (4.59–7.90%; P &gt;0.05). However, cows carrying the CT/CC genotype had a minimum carcass yield of 49.8%. There were eight haplotypes identified in heifers. The highest frequency was in combinations CT/CT (0.26), TT/CC (0.20), CC/TT (0.20), CC/CT (0.12), TT/CT (0.10). Heifers carrying the TT/CT genotype were characterized by the highest live weight (568.9 kg) and carcass weight (331.2 kg), exceeding the indicators of peers by 8.9–43.5 kg (1.59–8.28%; P &lt; 0.05, P &gt; 0.05) and 10.9–22.2 kg (3.40–7.18%; P &lt; 0.05, P &gt; 0.05), respectively. The maximum carcass yield was recorded in carriers of the CT/CC haplotype (60.7%). The best carcasses grade were observedin heifers with a combination of CC/TT and CT/CT genotypes. The highest categories (Prime and TopChoice) were assigned to 70.0 and 69.2% of carcasses, respectively. The superiority of haplotype CT/CT in the quality of meat raw materials was confirmed in cows. Thus, the combination of C73T and C528T polymorphisms in the leptin gene is associated with intra-breed variability in live weight, carcass weight and yield, and carcass grade in Aberdeen-Angus cattle. This research was performed with financial support from the project 0526-2021-0001 of RAS.