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Climate change is a major concern for the near future and for livestock breeding. Cattle breeding, due to its greenhouse gas emissions, is one of the most implicated industries. Consequently, the main future goals are to breed animals resilient to climate change, with the aim of lowering the livestock impact on the environment and selecting animals that will be able to resist different, unsuitable, and changing climates. The aim of this literature review is to compare the most recent studies on the response and adaptation of beef cattle breeds to extreme environments, in terms of genes and pathways involved. Beef breeding is just starting to implement genomics in its selection plans, and shedding light on the genomic responses to extreme climates could speed up and simplify the adaptation of these breeds to climate change. This review discusses the genes involved in climatic stress responses, including those related to extremely cold climates, in beef and dual‐purpose cattle breeds. Genes were associated with productive traits, coat and skin structure and development, thermotolerance, cellular physiology and DNA repair mechanisms, immune system, and fertility traits. The knowledge of genes and pathways involved in climate resilience should be taken into consideration for further selection in beef cattle breeding and could promote the valorization of local breeds adapted to extreme environmental conditions. The use of local or resilient breeds could enhance the environmental and social sustainability, animal welfare, and production, compared with the introduction of cosmopolitan breeds with uncertain adaptation in uncontrolled environmental areas. [ABSTRACT FROM AUTHOR]

In beef cattle breeding programs, various selection criteria have been proposed and employed with the aim of improving traits related to carcass composition and the quality of the final product, meat. However, the importance of genotype by environment interaction (G×E) for such traits is still not well understood. Our objectives were: 1) to investigate the importance of G×E on ultrasound carcass traits, growth and visual scores and 2) to estimate the genetic correlation of ultrasound carcass traits with growth and visual scores taking into account the G×E in Hereford and Braford cattle. A multiple-trait reaction norm model was fitted to the field records of 37,948 animals. With the exception of postweaning average daily weight gain (ADG), the G×E can lead to important changes in the ranking of estimated breeding values of sires across environments for all traits. Thus, models that consider heterogeneity of genetic variances along an environmental gradient may be considered more appropriate for genetic evaluations of animals reared under conditions similar to the present study. Based on estimates of genetic correlation, the quality of visual scores or ADG as indicators of carcass quality assessed by ultrasonography is dependent on the production environment. [ABSTRACT FROM AUTHOR]

Yunling cattle is a new breed of beef cattle bred in Yunnan Province, China, which has the advantages of fast growth, excellent meat quality, improved tolerance ability, and important landscape value. Copy number variation (CNV) is a significant source of gene structural variation and plays a crucial role in evolution and phenotypic diversity. Based on the latest reference genome ARS-UCD2.0, this study analyzed the genome-wide distribution of CNVs in Yunling cattle using short-read whole-genome sequencing data (n = 129) and single-molecule long-read sequencing data (n = 1), and a total of 16,507 CNVs were detected. After merging CNVs with overlapping genomic positions, 3,728 CNV regions (CNVRs) were obtained, accounting for 0.61% of the reference genome. The functional analysis indicated significant enrichment of CNVRs in 96 GO terms and 57 KEGG pathways, primarily related to cell adhesion, signal transduction, neuromodulation, and nutritional metabolism. Additionally, 111 CNVRs overlapped with 76 quantitative trait loci (QTLs), including Subcutaneous fat thicknessQTL, Longissimusmuscle areaQTL, andMarbling scoreQTL. Several CNVR-overlapping genes, including BZW1, AOX1, and LOC100138449, overlap with regions associated with meat color and quality QTLs. Furthermore, Vst analysis showed that PSMB4, ERICH1, SMC2, and PPP4R3A were highly divergent between Yunling and Brahman cattle. In summary, we have constructed the genomic CNV map of Yunling cattle for the first time using whole-genome resequencing. This provides valuable genetic variation resources for the study of the Yunling cattle genome and contributes to the study of economic traits in Yunling cattle. [ABSTRACT FROM AUTHOR]

This study evaluated the efficiency of a rapid reinsemination program allowing timed AI (TAI) every 21d (ReBreed21) in a commercial beef cow-calf operation. Nelore females from different parities (n = 2085) were synchronized for first TAI (D0 = TAI) using an estradiol/progesterone (E2/P4) protocol and assigned to one of three reinsemination programs: Resynch33 (n = 753), traditional resynch program with second TAI at D42 after first TAI; ReBreed21 (n = 687); or ReBreed21+EC (n = 670). The ReBreed females (n = 1357) received intravaginal P4 insert on D12, on D19 P4 was removed, and a dose of equine chorionic gonadotropin (eCG) was administered, then, ReBreed21 females received 0.6 mg of EC (ReBreed21+EC) or nothing (ReBreed21) and on D21, nonpregnancy (NP) was determined using Doppler ultrasound to detect corpus luteum (CL) blood flow (BF) (NP: <25 % BF pixels of total CL area) and NP cows received immediate TAI and GnRH to induce ovulation. Pregnancy diagnosis was performed at D33 after TAI following all TAIs. Cows considered pregnant at D21, based on CL BF, but NP on D33 were designated False-Positives (FP) and false negatives (FN) were number of nonpregnant cows/heifers on d21 based on the CL BF found to subsequently be pregnant on D33 divided by the total number pregnant. Pregnancy/AI (P/AI) did not differ for the first TAI (55.1 %) among the treatments. Heifers had similar P/AI at the second AI in all groups and similar to the first AI. Primiparous had greater P/AI in ReBreed21+EC and Resynch33 at s TAI compared to ReBreed21, 51.7 %, 55.8 %, 34.2 %, respectively. Multiparous had greater P/AI at second TAI in Resynch33 (60.9 %) than ReBreed21 programs (34.7 %). The percentage FP and FN among ReBreed21 programs did not differ, 13.8 and 0.2 %, respectively. Overall accumulative pregnancies on D21 of the breeding season were greater for ReBreed21 and ReBreed21+EC than Resynch33 (69.7 %, 71.6 %, and 55.5 %, respectively). However, on D42 of the breeding season, only heifers had greater pregnancies in ReBreed21 programs than Resynch33 (73.3 %, 74.3.6 %, and 63.2 %, respectively). Average days to pregnancy were less (P = 0.01) for ReBreed21 and ReBreed21+EC than Resynch33. Thus, the ReBreed21 strategy can improve the efficiency of TAI programs in beef cattle. Of interest, ReBreed21 was particularly effective in nulliparous, somewhat effective in primiparous when EC was added to the program, but relatively ineffective in multiparous beef cattle. • ReBreed21 increased cumulative pregnancies at D21 of breeding season in all parities. • Heifers had earlier pregnancies and more pregnancies on D42 using ReBreed21 programs. • Adding estradiol cypionate to ReBreed21 increased pregnancy/AI in primiparous cows. • Primiparous cows had earlier pregnancy using ReBreed21+EC than Resynch33. [ABSTRACT FROM AUTHOR]

Simple Summary: Whole-genome resequencing technology is widely applicated in the genetic breeding research of beef cattle. Pinan cattle are a specialized beef cattle population bred in Henan Province for more than 30 years. It has advantages in traits such as a fast growth rate, good reproductive performance, and high slaughter rate. But the genetic variation at the genome level of Pinan cattle has not been thoroughly explored. The whole-genome resequencing of a Pinan cattle population was conducted, combined with genome resequencing data of other cattle breeds, to detect the variations at the whole-genome level. Furthermore, the population genetic diversity and structure were analyzed, and the genes and loci under positive selection affecting important traits of Pinan cattle were identified using a selective sweep strategy. This study contributes to accelerating further breeding of the economic traits such as growth and reproductive performance in Pinan cattle. The breeding of high-quality beef cattle breeds is crucial for the development of animal husbandry, and whole-genome resequencing is widely applicated in the field of molecular breeding. Advantages in growth and reproductive traits exist in Pinan cattle compared with other cattle breeds, but there is limited research on its genomic mechanism. Using whole-genome resequencing, the genetic structure and genomic selection signatures in Pinan cattle were investigated in this study. Phylogenetic, cluster, and admixture analysis results indicated that Pinan cattle have a closer genetic relationship with Kholmogory cattle and China north cattle breeds. Through a selective sweep strategy, 207 and 54 candidate genes related to growth and reproduction and immunity, respectively, were identified in the Pinan cattle population. Given the crucial role of the glutamate–cysteine ligase catalytic (GCLC) gene in muscle antioxidative defense, the high frequency of allele T of the GCLC c.429 C>T locus in the Pinan cattle population might partially contribute to the advantages of Pinan cattle in growth performance. This study laid the foundation for the genetic improvement in Chinese local beef cattle and provide background for the studies on the growth and development of Pinan cattle. [ABSTRACT FROM AUTHOR]

Consumer perception of beef is heavily influenced by overall meat quality, a critical factor in the cattle industry. Genomics has the potential to improve important beef quality traits and identify genetic markers and causal variants associated with these traits through genomic selection (GS) and genome-wide association studies (GWAS) approaches. Transcriptomics, proteomics, and metabolomics provide insights into underlying genetic mechanisms by identifying differentially expressed genes, proteins, and metabolic pathways linked to quality traits, complementing GWAS data. Leveraging these functional genomics techniques can optimize beef cattle breeding for enhanced quality traits to meet high-quality beef demand. This paper provides a comprehensive overview of the current state of applications of omics technologies in uncovering functional variants underlying beef quality complexities. By highlighting the latest findings from GWAS, GS, transcriptomics, proteomics, and metabolomics studies, this work seeks to serve as a valuable resource for fostering a deeper understanding of the complex relationships between genetics, gene expression, protein dynamics, and metabolic pathways in shaping beef quality. [ABSTRACT FROM AUTHOR]

Object detection has been widely applied in daily life in recent years, including pedestrian detection, face recognition, and item counting. Among them, deep learning has brought some breakthroughs in the field of object detection. Therefore, object detection can be expected to be applied to the livestock industry, such as cow farms. However, some challenges have been posed by the existing object detection models. Particularly, beef cattle behavior can be hardly recognized under natural weather conditions, due mainly to the susceptibility to complex background interference, large model parameter size, computational complexity, and substantial memory usage for weight files. In this study, a lightweight (FABF-YOLOv8s) model was proposed to recognize the multiple behaviors of beef cattle using automatic scene distinction. Video data sources were collected from the real locations of beef cattle breeding. An all-weather natural scene dataset was constructed with the varying weather conditions. The beef cattle behavior was labeled in the scene dataset using LabelImg software and semiautomatic system annotation tools, thereby constructing a beef cattle behavior dataset. The natural scene dataset was trained using the FasterNet model. The output categories were obtained to verify the scene, and then automatically divide the weather scenes. The YOLOv8 model was obtained to determine the scene features before the detection of beef cattle behavior. The lightweight YOLOv8s network was also selected. The FasterNet lightweight model was used as the Backbone of the YOLOv8s, thus eliminating the computational redundancy of complex models for simple tasks. The Intra-Scale Feature Interaction (AIFI) was combined with the FasterNet lightweight model, in order to enhance the network focus among the features at the same scale, and then to capture the important features. The Weighted Bidirectional Feature Pyramid (BiFPN) was used as the Neck end network. The learnable weights were introduced to learn different input features. The top-down and bottom-up bidirectional paths were repeatedly applied to carry out the multi-scale feature fusion. The C2f-Faster feature extraction network was selected as the node. The parameter size and computational complexity were reduced during convolution. The accuracy of the model was improved to recognize the beef cattle behavior and subsequent deployment. The MPDIoU function was selected to overcome some limitations, such as cross occlusion of beef cattle, and the similar comparison between the prediction and bounding box, particularly with/without the overlap in the bounding box. The accuracy was guaranteed to compress the model structure, parameter quantity, and memory size, in order to obtain the detection model with high accuracy, small size, and strong generalization. An accurate identification of beef cattle behavior was achieved, such as standing, lying, feeding, drinking water, and licking. Finally, the visualization interface was designed to input the dataset in the form of images and videos. The recognition of beef cattle behavior was more intuitively demonstrated by the visualization system. The experimental results show that the FABF-YOLOv8s model (FasterNet, AIFI, BiFPN, and C2f-Faster, FABF) was achieved in an average accuracy, parameter volume, and floating-point computation of 93.6%, 4.51M, and 16.0 GFLOPs, respectively, on the self-built dataset of beef cattle behavior. Consequently, the average accuracy increased by 1.1, 4.7, and 0.4 percentage points, respectively, compared with the YOLOv5s, YOLOv7, and original YOLOv8s models. The parameter volume and floating-point computation decreased by 59.48% and 43.66%, respectively, compared with the YOLOv8s. The accuracy of detection was improved to minimize the computational complexity. The FasterNet’s automated scene distinction was achieved in an Accuracy, Precision, and F1-Score of 99.1%, 98.3%, and 96.7%, respectively. The FasterNet-FABFYOLOv8s model introduced the natural scene factors, with an average accuracy of 94.6%. There were the smaller parameter size and floating-point computation, whereas, the precision was higher, compared with the Faster-RCNN, SSD, FCOS, and DETR models. A lightweight recognition of beef cattle behavior was constructed under an automated scene distinction system. The finding can provide technical support to monitor the health status of beef cattle and automated intelligent breeding. [ABSTRACT FROM AUTHOR]

Introduction: Theileria orientalis Ikeda genotype is an emerging cattle disease in the US. Since 2017, when T. orientalis Ikeda was discovered in beef cattle in two counties in Virginia, cattle infections have risen to include ~67% of Virginia counties and 14 states. Consistent with New Zealand studies, many infected herds in Virginia were >90% positive upon initial testing without overt evidence of infection. Central bull tests present a unique opportunity to study the effects of T. orientalis Ikeda infections, as bulls from multiple source herds are consolidated. The objective of this study was to determine if infection with T. orientalis Ikeda affected the average daily gain (ADG), adjusted yearling weight (AYW) and breeding soundness of bulls at two test stations in Virginia over a period of years. Materials and methods: The bulls were fed and housed similarly to compare their growth performance and breeding soundness. For T. orientalis Ikeda testing, DNA was extracted from whole blood for quantitative polymerase chain reaction. Results: The number of bulls infected with T. orientalis Ikeda at initial delivery to the stations increased significantly over the years studied. Multivariable linear regression models, using Angus bulls from Virginia test stations, indicated no significant effect on ADG or AYW in bulls that became test positive during the test or were positive for the duration, compared to Angus bulls that were negative for the duration. At LOC A, the odds of passing a breeding soundness exam (BSE) were not significantly different for bulls that turned positive during the test or were positive for the duration, compared to bulls that were negative for the duration of the test. At LOC B, bulls that became positive during the test were 2.4 times more likely (95% CI: 1.165-4.995, p = 0.016) to pass their BSE compared to bulls that remained negative throughout the test. Discussion: We do not suppose that an obscured infection of T. orientalis Ikeda is protective for bulls to pass a BSE. However, this study demonstrates an obscured infection of T. orientalis Ikeda does not negatively affect weight gain or achievement of a satisfactory BSE rating at the central bull test stations in Virginia. [ABSTRACT FROM AUTHOR]

Background: The crossbreeding of specialized beef cattle breeds with Chinese indigenous cattle is a common method of genetic improvement. Xia'nan cattle, a crossbreed of Charolais and Nanyang cattle, is China's first specialized beef cattle breed with independent intellectual property rights. After more than two decades of selective breeding, Xia'nan cattle exhibit a robust physique, good environmental adaptability, good tolerance to coarse feed, and high meat production rates. This study analyzed the population genetic structure, genetic diversity, and genomic variations of Xia'nan cattle using whole-genome sequencing data from 30 Xia'nan cattle and 178 published cattle genomic data. Result: The ancestry estimating composition analysis showed that the ancestry proportions for Xia'nan cattle were mainly Charolais with a small amount of Nanyang cattle. Through the genetic diversity studies (nucleotide diversity and linkage disequilibrium decay), we found that the genomic diversity of Xia'nan cattle is higher than that of specialized beef cattle breeds in Europe but lower than that of Chinese native cattle. Then, we used four methods to detect genome candidate regions influencing the excellent traits of Xia'nan cattle. Among the detected results, 42 genes (θπ and CLR) and 131 genes (FST and XP-EHH) were detected by two different detection strategies. In addition, we found a region in BTA8 with strong selection signals. Finally, we conducted functional annotation on the detected genes and found that these genes may influence body development (NR6A1), meat quality traits (MCCC1), growth traits (WSCD1, TMEM68, MFN1, NCKAP5), and immunity (IL11RA, CNTFR, CCL27, SLAMF1, SLAMF7, NAA35, and GOLM1). Conclusion: We elucidated the genomic features and population structure of Xia'nan cattle and detected some selection signals in genomic regions potentially associated with crucial economic traits in Xia'nan cattle. This research provided a basis for further breeding improvements in Xia'nan cattle and served as a reference for genetic enhancements in other crossbreed cattle. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate the genetic parameters for age at first calving in Charolais and Limousine cattle breeds using animal model. The reproduction traits are influenced by genetic factors and environmental factors. The genetic factors are breed, individual and environmental factors are: climate condition and nutrition. The data consisted on 239 records for Charolais breed and 309 records for age at the first calving for Limousine breed. The data were from Romanian Breeding Association for Beef cattle. The age at the first calving was 792.92±6.77 days for Charolais breed and 813.83±6.09 days for Limousine breed. The heritability value for age at the first calving was 0.273 for Charolais and for Limousine breed was 0.275. The breeding values of cows with records for age at first calving were between −30.697 and 40.929 for Limousine breed were between −46.64 and 42.65. For improvement the reproduction traits it is necessary to improve the environmental conditions and supervision of reproduction activity in the farms and the selection of the best cows. The selection based on the breeding values of the cows determined the improvement of age at first calving. Improvement the reproduction traits increase the profitability of farms. [ABSTRACT FROM AUTHOR]

Simple Summary: Growth traits have been widely studied as economically important traits in the beef cattle industry. However, traditional studies often miss how these traits change under different environmental conditions, only focusing on single genetic changes that affect traits directly. In our study, we analyzed how genetics and environment interact to affect growth in beef cattle, considering four growth traits and two environmental factors. This analysis uncovered several genetic markers for growth traits that are not usually evident in standard studies, showing that some genes have effects that can be obliterated by environmental conditions Further testing showed whether these genetic markers are grouped in specific genes or functional pathways, helping us understand how genetics can influence growth under different environmental conditions. By uncovering novel genetic loci, genes, and candidate biological mechanisms associated with growth traits, our study provides valuable information for selection prediction and breeding decisions in the beef cattle industry. Complex traits are widely considered to be the result of a compound regulation of genes, environmental factors, and genotype-by-environment interaction (G × E). The inclusion of G × E in genome-wide association analyses is essential to understand animal environmental adaptations and improve the efficiency of breeding decisions. Here, we systematically investigated the G × E of growth traits (including weaning weight, yearling weight, 18-month body weight, and 24-month body weight) with environmental factors (farm and temperature) using genome-wide genotype-by-environment interaction association studies (GWEIS) with a dataset of 1350 cattle. We validated the robust estimator's effectiveness in GWEIS and detected 29 independent interacting SNPs with a significance threshold of 1.67 × 10−6, indicating that these SNPs, which do not show main effects in traditional genome-wide association studies (GWAS), may have non-additive effects across genotypes but are obliterated by environmental means. The gene-based analysis using MAGMA identified three genes that overlapped with the GEWIS results exhibiting G × E, namely SMAD2, PALMD, and MECOM. Further, the results of functional exploration in gene-set analysis revealed the bio-mechanisms of how cattle growth responds to environmental changes, such as mitotic or cytokinesis, fatty acid β-oxidation, neurotransmitter activity, gap junction, and keratan sulfate degradation. This study not only reveals novel genetic loci and underlying mechanisms influencing growth traits but also transforms our understanding of environmental adaptation in beef cattle, thereby paving the way for more targeted and efficient breeding strategies. [ABSTRACT FROM AUTHOR]

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The experiment was conducted from 2017 to 2019 at the Research Institute of Mountain Stockbreeding and Agriculture, Troyan. The aim was to determine the quality and nutritional value of foliar fodder from introduced bamboo used in raising hornless Hereford beef cattle breed, and its impact on the appetite of ruminants fed with the dry fodder mass. A chemical analysis included characteristics, such as moisture, crude protein, crude fat, carbohydrates and crude ash. Chemical analysis data were used to calculate the energy value of the introduced bamboo. Its impact on consumption and appetite was monitored. The results obtained indicate high digestibility (77.38-83.39%), which correlates positively with crude protein content (r = 0.867), mineral substances (r = 0.722) and minerals, such as N, P and Ca (r = 0.848 - 0.901) in dry matter. The energy value of fodder is highly regression dependent on the crude fat content at a coefficient of determination of R2 = 0.9942 (for GE) and R2 = 0.9999 (for EE). The energy value expressed in feed unit for milk performed the highest regression dependence with the concentration of ADF (R2 = 0.9996), NFE (R2 = 0.9995) and EE (R2 = 0.9994). The content of the basic nutrients is in the following ranges: crude protein 11.39 to 18.60, NFE from 27.8 to 38.32, minerals from 9.36 to 11.79% and crude fat from 1.33 to 3.45%. Bamboo foliar fodder is highly palatable (44.2%). In the dry matter content, the amount of crude protein ranged from 11.39 to 18.60%, nitrogen-free extractable substances from 27.28 to 38.32%, minerals from 9.36 to 11.79% and crude fat from 1.33 to 3.45%. [ABSTRACT FROM AUTHOR]

Feed efficiency plays a major role in the overall profitability and sustainability of the beef cattle industry, as it is directly related to the reduction of the animal demand for input and methane emissions. Traditionally, the average daily feed intake and weight gain are used to calculate feed efficiency traits. However, feed efficiency traits can be analysed longitudinally using random regression models (RRMs), which allow fitting random genetic and environmental effects over time by considering the covariance pattern between the daily records. Therefore, the objectives of this study were to: (1) propose genomic evaluations for dry matter intake (DMI), body weight gain (BWG), residual feed intake (RFI) and residual weight gain (RWG) data collected during an 84‐day feedlot test period via RRMs; (2) compare the goodness‐of‐fit of RRM using Legendre polynomials (LP) and B‐spline functions; (3) evaluate the genetic parameters behaviour for feed efficiency traits and their implication for new selection strategies. The datasets were provided by the EMBRAPA–GENEPLUS beef cattle breeding program and included 2920 records for DMI, 2696 records for BWG and 4675 genotyped animals. Genetic parameters and genomic breeding values (GEBVs) were estimated by RRMs under ssGBLUP for Nellore cattle using orthogonal LPs and B‐spline. Models were compared based on the deviance information criterion (DIC). The ranking of the average GEBV of each test week and the overall GEBV average were compared by the percentage of individuals in common and the Spearman correlation coefficient (top 1%, 5%, 10% and 100%). The highest goodness‐of‐fit was obtained with linear B‐Spline function considering heterogeneous residual variance. The heritability estimates across the test period for DMI, BWG, RFI and RWG ranged from 0.06 to 0.21, 0.11 to 0.30, 0.03 to 0.26 and 0.07 to 0.27, respectively. DMI and RFI presented within‐trait genetic correlations ranging from low to high magnitude across different performance test‐day. In contrast, BWG and RWG presented negative genetic correlations between the first 3 weeks and the other days of performance tests. DMI and RFI presented a high‐ranking similarity between the GEBV average of week eight and the overall GEBV average, with Spearman correlations and percentages of individuals selected in common ranging from 0.95 to 1.00 and 93 to 100, respectively. Week 11 presented the highest Spearman correlations (ranging from 0.94 to 0.98) and percentages of individuals selected in common (ranging from 85 to 94) of BWG and RWG with the average GEBV of the entire period of the test. In conclusion, the RRM using linear B‐splines is a feasible alternative for the genomic evaluation of feed efficiency. Heritability estimates of DMI, RFI, BWG and RWG indicate enough additive genetic variance to achieve a moderate response to selection. A new selection strategy can be adopted by reducing the performance test to 56 days for DMI and RFI selection and 77 days for BWG and RWG selection. [ABSTRACT FROM AUTHOR]

Introduction: Nellore cattle (Bos taurus indicus) is the main beef cattle breed raised in Brazil. This breed is well adapted to tropical conditions and, more recently, has experienced intensive genetic selection for multiple performance traits. Over the past 43 years, an experimental breeding program has been developed in the Institute of Animal Science (IZ, Sertaozinho, SP, Brazil), which resulted in three differentially-selected lines known as Nellore Control (NeC), Nellore Selection (NeS), and Nellore Traditional (NeT). The primary goal of this selection experiment was to determine the response to selection for yearling weight (YW) and residual feed intake (RFI) on Nellore cattle. The main objectives of this study were to: 1) identify copy number variation (CNVs) in Nellore cattle from three selection lines; 2) identify and characterize CNV regions (CNVR) on these three lines; and 3) perform functional enrichment analyses of the CNVR identified. Results: A total of 14,914 unique CNVs and 1,884 CNVRs were identified when considering all lines as a single population. The CNVRs were non-uniformly distributed across the chromosomes of the three selection lines included in the study. The NeT line had the highest number of CNVRs (n = 1,493), followed by the NeS (n = 823) and NeC (n = 482) lines. The CNVRs covered 23,449,890 bp (0.94%), 40,175,556 bp (1.61%), and 63,212,273 bp (2.54%) of the genome of the NeC, NeS, and NeT lines, respectively. Two CNVRs were commonly identified between the three lines, and six, two, and four exclusive regions were identified for NeC, NeS, and NeT, respectively. All the exclusive regions overlap with important genes, such as SMARCD3, SLC15A1, and MAPK1. Key biological processes associated with the candidate genes were identified, including pathways related to growth and metabolism. Conclusion: This study revealed large variability in CNVs and CNVRs across three Nellore lines differentially selected for YW and RFI. Gene annotation and gene ontology analyses of the exclusive CNVRs to each line revealed specific genes and biological processes involved in the expression of growth and feed efficiency traits. These findings contribute to the understanding of the genetic mechanisms underlying the phenotypic differences among the three Nellore selection lines. [ABSTRACT FROM AUTHOR]

Background: Recursive models are a category of structural equation models that propose a causal relationship between traits. These models are more parameterized than multiple trait models, and they require imposing restrictions on the parameter space to ensure statistical identification. Nevertheless, in certain situations, the likelihood of recursive models and multiple trait models are equivalent. Consequently, the estimates of variance components derived from the multiple trait mixed model can be converted into estimates under several recursive models through LDL′ or block-LDL′ transformations. Results: The procedure was employed on a dataset comprising five traits (birth weight—BW, weight at 90 days—W90, weight at 210 days—W210, cold carcass weight—CCW and conformation—CON) from the Pirenaica beef cattle breed. These phenotypic records were unequally distributed among 149,029 individuals and had a high percentage of missing data. The pedigree used consisted of 343,753 individuals. A Bayesian approach involving a multiple-trait mixed model was applied using a Gibbs sampler. The variance components obtained at each iteration of the Gibbs sampler were subsequently used to estimate the variance components within three distinct recursive models. Conclusions: The LDL′ or block-LDL′ transformations applied to the variance component estimates achieved from a multiple trait mixed model enabled inference across multiple sets of recursive models, with the sole prerequisite of being likelihood equivalent. Furthermore, the aforementioned transformations simplify the handling of missing data when conducting inference within the realm of recursive models. [ABSTRACT FROM AUTHOR]

The aim of the experiment was to study the effects of different levels of antimicrobial peptides on the growth performance, rumen fermentation parameters, serum immunity, and breeding economic benefits of Simmental hybrid beef cattle. A total of 32 healthy Simmental crossbred beef cattle with similar body weight were randomly divided into four groups, with eight replicates per group and one beef cattle per replicate. Beef cattle in the control group were fed a basal diet, and those in the test group A, group B, and group C were fed diets containing 2, 4, 8 g/(head·d) antimicrobial peptides, respectively. The pre-test lasted for seven days and the formal test lasted for 150 days. The results showed that compared with the control group, the final weight and average daily gain in the test group B and group C were significantly increased (P<0.05), while the ratio of feed to gain was significantly decreased (P<0.05). The pH value and bacterial protein concentration of rumen fluid in test group B and group C were significantly increased (P<0.05), and the ratio of ethylene to propylene was significantly decreased (P<0.05). The rumen acetic acid concentration in all the test groups was significantly decreased (P<0.05). The serum level of interleukin-4 was significantly increased (P<0.05), and the serum level of interleukin-6 was significantly decreased in all the test groups (P<0.05). The levels of interleukin-10, immunoglobulin M and immunoglobulin G in test group B and group C were significantly increased (P<0.05). Compared with the control group, the weight gain income in the test group A, group B, and group C was increased by 10.40%, 22.34%, and 23.55%, and the profit was increased by 19.31%, 46.54%, and 48.45%, respectively. The study indicates that adding appropriate amount of antimicrobial peptides in beef cattle breeding can improve growth performance, promote rumen fermentation function, enhance immune function and increase breeding profits, and adding 4 g/(head ·d) antimicrobial peptides is more appropriate. [ABSTRACT FROM AUTHOR]

Italy has a long history in beef production, with local breeds such as Marchigiana, Chianina, Romagnola, Maremmana, and Podolica which produce high-quality meat. Selection has improved meat production, precocity, growth ability and muscle development, but the genetic determinism of such traits is mostly unknown. Using 33K SNPs-data from young bulls (N = 4064) belonging to these five Italian breeds, we demonstrated that the Maremmana and Podolica rustic breeds are closely related, while the specialised Marchigiana, Chianina, and Romagnola breeds are more differentiated. A genome-wide association study for growth and muscle development traits (average daily gain during the performance test, weight at 1 year old, muscularity) was conducted in the five Italian breeds. Results indicated a region on chromosome 2, containing the myostatin gene (MSTN), which displayed significant genome-wide associations with muscularity in Marchigiana cattle, a breed in which the muscle hypertrophy phenotype is segregating. Moreover, a significant SNP on chromosome 14 was associated, in the Chianina breed, to muscularity. The identification of diverse genomic regions associated with conformation traits might increase our knowledge about the genomic basis of such traits in Italian beef cattle and, eventually, such information could be used to implement marker-assisted selection of young bulls tested in the performance test. [ABSTRACT FROM AUTHOR]

The production performance and rumen bacterial diversity were compared for different silage-based diets supplemented with common concentrate or bio-concentrate to develop an alternative of common concentrate for fatten cattle feeding. The daily gain of fattening cattle was increased by 0. 99 kg and 1.04 kg, respectively, when fed with single corn silage or mixed silagebased diet supplemented with bio-concentrate. There was no significant difference in water loss rate and cooked meat rate among groups (P>0.05), but the tenderness of beef in the bio-concentrate group was significantly higher than that in the common concentrate group (P<0.05). There were no adverse effects on beef quality and blood biochemical indexes in each group. Compared with the normal concentrate group, the OTU number and α-diversity index of rumen microorganisms of fattening cattle fed with mixed silage as the basic diet supplemented with bioconcentrate increased significantly. At generic level, the relative abundances of Prevotella, Porphyromonadaceae (unclassified), and Succiniclasticum were increased by adding bio-concentrate in the diets based on mixed silage and single sorghum silage. Relative abundances of Bacteroidetes (unclassified), Ruminococcaceae (unclassified), and Firmicutes (unclassified) decreased. In conclusion, the bio-concentrate might be a better choice than common concentrate for beef cattle breeding. [ABSTRACT FROM AUTHOR]

In order to study the effects of steam-flaked corn on the growth performance, slaughter performance, and meat quality of beef cattle, 40 Simmental crossbred beef cattle with a body weight of (224.05±14.56) kg were randomly divided into four groups with five replicates per group and two beef cattle per replicate. Crushed corn was added to the diet of the control group, and 33%, 66%, and 100% steam-flaked corn were used to replace the crushed corn in test group I ~ group III, respectively. The pre-feeding period lasted for seven days, and the formal test period lasted for 120 days. The results showed that the final weight of the group II and group III increased by 6.27% (P<0.05) and 10.64% (P<0.01) compared to the control group, respectively. The total weight gain of the group I ~ group III increased by 7.56% (P<0.05), 21.29% (P<0.01), and 33.45% (P<0.01) compared to the control group, respectively. The live weight before slaughter of the group I ~ group III increased by 2.64% (P<0.05), 6.59% (P<0.01), and 10.25% P<0.01) compared to the control group, respectively. The feed to gain ratio of the group II and group III was extremely lower than that of the control group (P<0.01). The carcass weight and net meat weight of the group II and group III were extremely higher than those of the control group (P<0.01). The content of crude protein in beef in the group II and group III was extremely higher than that in the control group (P<0.01). The crude fat content in the group III was significantly higher than that in the control group (P<0.05). The pH45 min value and water loss rate of the group III were significantly lower than those of the control group (P<0.05). The aquaculture benefits of experimental group I ~ group III were increased by 15.36%, 48.04%, and 77.98% compared to the control group, respectively. The study indicates that replacing common crushed corn with steam-flaked corn can improve the growth performance and slaughter performance of Simmental crossbred beef cattle, improve the quality of beef, and improve the economic benefit of beef cattle breeding. Replacing the common crushed corn with 100% steam-flaked corn in the diet has a better effect. [ABSTRACT FROM AUTHOR]

This article provides an overview of beef production and carcass evaluation in Brazil. It highlights Brazil's significant role in the global beef market and its record-breaking export revenues. However, Brazil lacks a national carcass grading system, with slaughterhouses using their own metrics to meet market demands. The current standard for carcass classification in Brazil is based on dentition, gender, carcass weight, and subcutaneous/external fat scores. The article also discusses beef cattle production systems, market statistics, and the need for a new Brazilian classification and grading system that incorporates eating quality parameters and technological advancements. [Extracted from the article]

Yunling cattle is a new breed of beef cattle bred in Yunnan Province, China. It is bred by crossing the Brahman, the Murray Grey and the Yunnan Yellow cattle. Yunling cattle can adapt to the tropical and subtropical climate environment, and has good reproductive ability and growth speed under high temperature and high humidity conditions, it also has strong resistance to internal and external parasites and with good beef performance. In this study, we generated a high-quality chromosome-level genome assembly of a male Yunling cattle using a combination of short reads sequencing, PacBio HiFi sequencing and Hi-C scaffolding technologies. The genome assembly(3.09 Gb) is anchored to 31 chromosomes(29 autosomes plus one X and Y), with a contig N50 of 35.97 Mb and a scaffold N50 of 112.01 Mb. It contains 1.62 Gb of repetitive sequences and 20,660 protein-coding genes. This first construction of the Yunling cattle genome provides a valuable genetic resource that will facilitate further study of the genetic diversity of bovine species and accelerate Yunling cattle breeding efforts. [ABSTRACT FROM AUTHOR]

Simple Summary: Progressive ataxia is an autosomal recessive defect that is lethal due to the irreversible changes it causes to the brain and spinal cord. Only homozygous carriers of the mutated KIF1C allele manifest progressing clinical signs, mostly no earlier than 12–24 months of age. The objectives of this field study were to determine the prevalence of the mutated KIF1C allele, uncover its associations with growth and muscle conformation, and build awareness of this lethal condition among beef cattle breeders in Germany. A total of 1315 samples was sent in for mutation testing. Prevalence of the mutated KIF1C allele was 11.75%, resulting from 293 heterozygous and 8 homozygous mutant animals. Homozygous carriers of the mutated KIF1C allele showed a significant superiority in estimated breeding values for daily weight gain and muscle conformation. In order to reduce the frequency of the mutated KIF1C allele, genetic testing should be introduced for Charolais cattle and should be mandatory for all Charolais breeding bulls. It is important to create awareness of this condition among beef cattle breeders, in addition to the possibilities of preventing the number of affected animals. In addition, genetic testing of eight further beef, dual-purpose, or dairy cattle breeds revealed that two German Angus cattle showed heterozygous mutations for the KIF1C A-allele; therefore, we recommend genetic testing of German Angus to prevent the spread of the KIF1C allele. Bovine progressive ataxia in Charolais cattle was first described in the 1970s; then, cases were reported in Charolais worldwide. A homozygous loss-of-function mutation within the KIF1C gene (c.608G>A) was found to be responsible for this neurodegenerative disease. The aim of this study was to determine whether the mutated KIF1C allele segregates in the German Charolais population and whether the estimated breeding values for growth and muscle conformation are associated with the mutated genotypes. Genetic test results of the KIF1C:c.608G>A variant were available for 1315 Charolais cattle from 35 herds located in Germany. In addition, 324 samples from eight other beef cattle breeds were tested for the mutated KIF1C allele. We were able to demonstrate that the KIF1C mutation is common, with a frequency of 11.75% in the German Charolais population. All but two of the eight (2/8 = 25%) homozygous mutated individuals showed clinical signs consistent with progressive ataxia. The estimated breeding values of muscle conformation in 200- and 365-day-old animals indicated a significant superiority for homozygous mutated animals when compared either with heterozygous or homozygous wild-type genotypes; this was also the case for heterozygous genotypes in comparison with homozygous wild-type genotypes. For the estimated breeding values of daily weight gain in 200- and 365-day-old animals, the significant differences between homozygous mutated and heterozygous or wild-type genotypes were in favour of the homozygous mutant animals. There were no differences in the estimated maternal breeding values among all three KIF1C genotypes. For the first time, two German Angus cattle carrying the KIF1C mutation heterozygous were detected. The breeders' survey highlighted that increased awareness would facilitate increased conviction among breeders of the need for genetic testing in order to eliminate the lethal KIF1C allele. [ABSTRACT FROM AUTHOR]

Numerous studies have shown that combining populations from similar or closely related genetic breeds improves the accuracy of genomic predictions (GP). Extensive experimentation with diverse Bayesian and genomic best linear unbiased prediction (GBLUP) models have been developed to explore multi-breed genomic selection (GS) in livestock, ultimately establishing them as successful approaches for predicting genomic estimated breeding value (GEBV). This study aimed to assess the effectiveness of using BayesR and GBLUP models with linkage disequilibrium (LD)-weighted genomic relationship matrices (GRMs) for genomic prediction in three different beef cattle breeds to identify the best approach for enhancing the accuracy of multi-breed genomic selection in beef cattle. Additionally, a comparison was conducted to evaluate the predictive precision of different marker densities and genetic correlations among the three breeds of beef cattle. The GRM between Yunling cattle (YL) and other breeds demonstrated modest affinity and highlighted a notable genetic concordance of 0.87 between Chinese Wagyu (WG) and Huaxi (HX) cattle. In the within-breed GS, BayesR demonstrated an advantage over GBLUP. The prediction accuracies for HX cattle using the BayesR model were 0.52 with BovineHD BeadChip data (HD) and 0.46 with whole-genome sequencing data (WGS). In comparison to the GBLUP model, the accuracy increased by 26.8% for HD data and 9.5% for WGS data. For WG and YL, BayesR doubled the within-breed prediction accuracy to 14.3% from 7.1%, outperforming GBLUP across both HD and WGS datasets. Moreover, analyzing multiple breeds using genomic selection showed that BayesR consistently outperformed GBLUP in terms of predictive accuracy, especially when using WGS. For instance, in a mixed reference population of HX and WG, BayesR achieved a significant accuracy of 0.53 using WGS for HX, which was a substantial enhancement over the accuracies obtained with GBLUP models. The research further highlights the benefit of including various breeds in the reference group, leading to enhanced accuracy in predictions and emphasizing the importance of comprehensive genomic selection methods. Our research findings indicate that BayesR exhibits superior performance compared to GBLUP in multi-breed genomic prediction accuracy, achieving a maximum improvement of 33.3%, especially in genetically diverse breeds. The improvement can be attributed to the effective utilization of higher single nucleotide polymorphism (SNP) marker density by BayesR, resulting in enhanced prediction accuracy. This evidence conclusively demonstrates the significant impact of BayesR on enhancing genomic predictions in diverse cattle populations, underscoring the crucial role of genetic relatedness in selection methodologies. In parallel, subsequent studies should focus on refining GRM and exploring alternative models for GP. [ABSTRACT FROM AUTHOR]

Robertsonian translocation 1;29 (rob(1;29)), a widespread chromosomal anomaly affecting cattle fertility, appears to have originated from a common ancestor. This study utilizes routine SNP data to investigate the chromosomal region associated with rob(1;29) and confirm the presence of a shared haplotype among carriers in diverse Italian breeds. Three datasets were employed: Dataset 1 included 151 subjects from 5 beef cattle breeds genotyped with the GGP Bovine 33 k SNP chip; Dataset 2 encompassed 800 subjects from 32 Italian breeds genotyped with the Illumina 50 k SNP chip, sourced from the BOVITA dataset; Dataset 3 combined Dataset 2 with 21 karyologically tested subjects from breeds with a high carrier frequency, genotyped using the Affymetrix 65 K SNP chip. FST analysis pinpointed a distinctive genomic region on the first six Mb of BTA29, the centromeric region involved in the translocation. Haplotype comparisons within this non-recombining region revealed a common haplotype shared among all carriers, supporting the theory of a common ancestor. Principal component and haplotype analysis allowed clear differentiation of rob(1;29) homozygous and heterozygous carriers. Expanding to Dataset 2 revealed rob(1;29) carriers in unexpected breeds, all sharing the same ancestral haplotype. Notably, previously untested breeds, including Cinisara, exhibited a high carrier prevalence (nearly 50%), confirmed by karyological analysis. This study validates the presence of a shared haplotype among all identified rob(1;29) carriers, reinforcing the common ancestor theory as the origin of this translocation's spread throughout the cattle population. Furthermore, it underscores the potential of SNP data analysis as a rapid, accurate, and cost-effective tool for broad rob(1;29) screening, given the translocation's consistent nature across all analyzed breeds. [ABSTRACT FROM AUTHOR]

Raising and fattening cattle for meat production is an important source of profit, playing an important role in the agriculture' intensification and efficiency. This is due to the superior utilisation of cheap fodder resources that are transformed into meat, a product with high biological and nutritive value. Increasing the meat production of the Aberdeen Angus breed, in order to improve the production qualities, adapted in the north-eastern region of Moldova, requires knowledge of the maintenance and feeding systems applied in the farms from the studied area. [ABSTRACT FROM AUTHOR]

Simple Summary: Historically, Korea has been an agrarian society where cattle played a significant role in Korean culture as working animals. However, in recent decades, there has been an increase in meat demand and the expansion of the Korean economy. This shift has led to the predominant use of native Korean Hanwoo cattle for beef production since the 1960s. Genetic improvement programs for Hanwoo cattle traditionally focused on carcass and growth qualities due to the accessibility of trait information and the simplicity of analysis techniques, rather than reproductive traits. However, there has been a recent surge of interest in genetic analyses of the reproductive traits of Hanwoo cattle because these traits significantly impact calf productivity. To enhance beef production and the overall profitability of Hanwoo farming, it is imperative to implement genomic predictions for age at first calving (AFC), calving interval (CI), gestation length (GL), and number of artificial inseminations per conception (NAIPC) to better understand and improve their response to selection. This study aimed to estimate heritability and the accuracy of genomic estimated breeding values (GEBVs) using genomic best linear unbiased prediction (GBLUP) and Bayesian methods (BayesB, BayesLASSO, and BayesR) for traits under study. Our analysis revealed relatively lower heritability values for these traits and indicated that the accuracy of genomic prediction across all methods applied was similarly reduced, likely due to the inherent lower heritability of reproductive traits. As a result, the findings of this study provide valuable insights into the genetic breeding programs of the beef cattle industry. This study aimed to predict the accuracy of genomic estimated breeding values (GEBVs) for reproductive traits in Hanwoo cows using the GBLUP, BayesB, BayesLASSO, and BayesR methods. Accuracy estimates of GEBVs for reproductive traits were derived through fivefold cross-validation, analyzing a dataset comprising 11,348 animals and employing an Illumina Bovine 50K SNP chip. GBLUP showed an accuracy of 0.26 for AFC, while BayesB, BayesLASSO, and BayesR demonstrated values of 0.28, 0.29, and 0.29, respectively. For CI, GBLUP attained an accuracy of 0.19, whereas BayesB, BayesLASSO, and BayesR scored 0.21, 0.24, and 0.25, respectively. The accuracy for GL was uniform across GBLUP, BayesB, and BayesR at 0.31, whereas BayesLASSO showed a slightly higher accuracy of 0.33. For NAIPC, GBLUP showed an accuracy of 0.24, while BayesB, BayesLASSO, and BayesR recorded 0.22, 0.27, and 0.30, respectively. The variation in genomic prediction accuracy among methods indicated Bayesian approaches slightly outperformed GBLUP. The findings suggest that Bayesian methods, notably BayesLASSO and BayesR, offer improved predictive capabilities for reproductive traits. Future research may explore more advanced genomic approaches to enhance predictive accuracy and genetic gains in Hanwoo cattle breeding programs. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of gender status and concentrate supplementation level on the fattening process in beef crosses with various maturity types. The animals were fattened in two dietary treatments groups differing in the level of concentrate supplementation, analogous in terms of sire breed and gender status. Feed intake was recorded. Body weight, dry matter intake and feed efficiency were analysed using the Gompertz model in 36 bulls and 36 steers, crosses of Polish Holstein-Friesian (PHF) cows and beef bulls (Hereford -- HH, Limousin -- LM, Charolais -- CH), aged 300 to 550 days. The performance of the Gompertz model was assessed by calculating the coefficient of determination. Results showed that animals of all genotypes fed diets with a higher concentrate level were characterised by a higher growth rate. PHF x HH crosses reached their peak growth rate between 400 and 450 days of age, regardless of feeding level. On the other hand, PHF x LM crosses reached the maximum growth rate faster at the higher level of concentrate supplementation compared to the lower level (350 vs. 450 days of age). Therefore, PHF x CH bulls should be fed more intensively than steers due to the strong effect of gender status on their relative growth rate and feed efficiency. The analysis of growth curves in beef cattle can improve feed efficiency and help meet the nutrient requirements of animals at different growth stages. Predictive models could be used to estimate the breeding value of beef cattle and support selection for economically significant traits. [ABSTRACT FROM AUTHOR]

The United States beef industry is a major stakeholder in national and international agriculture and is driven by technological innovations and beef producers in all 50 states. Beef cattle breed associations are essential to the success of the industry as they not only maintain breed pedigrees but also disseminate vital information to their members. The magazines of beef cattle breed associations are a primary source of communication for U.S. beef producers. Goals for this study were to determine what information beef producers use from their beef breed association magazines, what information they want to see more of in beef breed association magazines, and if producers prefer the magazines in a print or digital format. Uses and gratifications theory, which focuses on the reasons why individuals choose to use a specific communication medium; the effect the medium has on the individual; and the gratifications received through its use, guided this study, along with gatekeeping theory. We used a descriptive quantitative survey research design to disseminate a survey instrument to members of six U.S. beef breed associations. Results revealed a large percentage of survey respondents prefer their beef breed association magazines in a print format. Additionally, results indicate that respondents use association magazines for a variety of information, and they want to see more information related to breed improvement strategies, genetic selection, and technological advancements. Results revealed insightful uses of magazine topics related to breed associations and can be used as a resource to help guide the editorial content of the magazines. We recommend beef cattle breed associations continue to provide magazine content in both print and digital formats and include editorial topics curated to the needs of the beef producers using their magazines. [ABSTRACT FROM AUTHOR]

Lipid and energy metabolism are major constituents of mammal growth and thus fattening performance of cattle. This study was designed to evaluate the effects of polymorphisms in lipid and energy metabolism-related genes including oxidized low-density lipoprotein receptor 1 (OLR1), lactoferrin (LTF), stearoyl-CoA desaturase (SCD), beta-lactoglobulin (LGB), thyroglobulin (TG), annexin A9 (ANXA9), myogenic factor 5 (MYF5), protein kinase AMP-activated non-catalytic subunit gamma 3 (PRKAG3), and pituitary-specific transcriptional factor 1 (PIT1), on fattening performance in Simmental cattle. A total of 72 purebred Simmental bulls with a similar initial age and weight were fattened on the same farm for 10 months. Association analysis was performed using linear mixed models. The OLR1 marker was significantly associated with the final weight (FW), hot carcass weight (HCW), chilled carcass weight (CCW), dressing percentage (DP), and total weight gain (TWG). SCD affected the FW, TWG, and average daily live weight gain (ADWG). The present results clearly demonstrated the significant impact of the TG marker on fattening performance. It was highly significantly associated with the FW, HCW, CCW, and TWG. The SCD × TG and the OLR1 × TG interactions had remarkable effects on the traits analyzed. The GACC and CCCC haplotypes of the SCD × TG and OLR1 × TG, respectively, were found to be powerful markers for fattening performance in Simmentals. Novel associations in this study may be useful for further genetic evaluations to improve beef cattle breeding. [ABSTRACT FROM AUTHOR]

The biological clock (also known as circadian clock) is closely related to growth and development, metabolism, and diseases in animals. As a part of the circadian clock, the cryptochrome circadian regulator 1 (CRY1) gene is involved in the regulation of biological processes such as osteogenesis, energy metabolism and cell proliferation, however, few studies have been reported on the relationship between this gene and animal carcass traits. Herein, a total of four insertion/deletion (InDel) loci within the CRY1 gene were detected in Shandong Black Cattle Genetic Resource (SDBCGR) population (n = 433). Among them, the P1-6-bp-del locus was polymorphic in population of interest. Moreover, the P1-6-bp-del locus showed two genotypes, with a higher insertion/insertion (II) genotype frequency (0.751) than insertion/deletion (ID) genotype frequency (0.249). Correlation analysis showed that the P1-6-bp-del locus polymorphisms were significantly associated with twenty carcass traits (e.g., slaughter weight, limb weight, and belly meat weight). Individuals with II genotype were significantly better than those with ID genotype for eighteen carcass traits. Therefore, the P1-6-bp-del locus of the CRY1 gene can be used as a molecular marker for beef cattle breeding. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of fermented Chinese herb residues on the growth performance, nutrient apparent digestibility, serum biochemical indices and microflora of Simmental beef cattle during the fattening period. Twenty-four healthy Simmental beef cattle with an average body weight of 358.54 ± 65.63 kg were randomly divided into four treatment groups, with 6 replicates. The dietary treatments were as follows: I: basal diet; II, III and IV: 10% corn husk in the diet was replaced by Chinese herb residue, enzyme-fermented residue, and enzyme bacteria co-fermented residue, respectively. The experimental period was 49 days. There was no significant difference in the growth performance of beef cattle (p > 0.05). The ether extract (EE) apparent digestibility of groups III and IV was significantly higher than that of group I (p < 0.05); the apparent digestibility values of nitrogen free extract (NFE) and total phosphorus (P) in group IV were significantly lower than those in the other groups (p < 0.05). The maleic dialdehyde (MDA) contents in groups I and II were significantly higher than those in groups III and IV (p < 0.05). The ACE and Chao1 indices of groups I and III were significantly higher than those of groups II and IV (p < 0.05). The Shannon indices of groups I and III were significantly higher than that of group II (p < 0.05). The abundance of Firmicutes in group III was significantly lower than that in group II (p < 0.05). In conclusion, fermented Chinese herb residues could replace 10% corn husk and be used in beef cattle breeding. Dietary replacement of 10% corn husk with Chineseherb residue can improve nutrient digestibility of fattening cattle. Concentrate containing 10% fermented Chinese herb residues as a corn husk replacement can be used for feedlot cattle without adverse effects. [ABSTRACT FROM AUTHOR]

Wagyu is recognized for producing marbled beef with high nutritional value and flavor. Reportedly, Wagyu has been widely used to improve the meat quality of local breeds around the world. However, studies on the genetic mechanism of meat quality in Wagyu at the whole‐genome level are rarely reported. Here, whole‐genome sequencing data of 11 Wagyu and 115 other individuals were used to explore the genomic variations and genes under selection pressure in Wagyu. A total of 31 349 non‐synonymous variants and 53 102 synonymous variants were identified in Wagyu. The population structure analysis showed that Wagyu had the closest genetic relationship with Mishima–Ushi cattle and was apparently separated from other cattle breeds. Then, composite likelihood ratio (CLR), integrated haplotype score, fixation index and cross‐population composite likelihood ratio (XP‐CLR) tests were performed to identify the candidate genes under positive selection in Wagyu. In total, 770 regions containing 312 genes were identified by at least three methods. Among them, 97 regions containing 27 genes were detected by all four methods. We specifically illustrate a list of interesting genes, including LRP2BP, GAA, CACNG6, CXADR, GPCPD1, KLF2, KLF13, SOX5, MYBPC1, SLC25A10, ATP8A1 and MYH15, which are associated with lipid metabolism, fat deposition, muscle development, bone development, feed intake and growth traits in Wagyu. This is the first study to explore the genomic variations and selection signatures of Wagyu at the whole‐genome level. These results will provide significant help to beef cattle improvement and breeding. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to use a meta-analysis to identify the correlation between linear body measurements, including body length (BL), wither height (WH), heart girth (HG), and body volume (BV), and body weight in beef cattle by breed, sex, and age as categories. Materials and Methods: These results can be used as a method for predicting beef cattle body weight. This study used systematic review and meta-analysis guidelines to create a checklist. The first stage was searching for papers relevant to the study objectives. The second stage was searching using the keywords beef cattle, body weight, body measurement, and correlation. The third stage was reviewing the title and abstract. The fourth stage was abstracting information from selected papers, and the last stage was tabulating data. Results: The results from this study were obtained, and 32 papers were eligible for the meta-analysis stage. The correlation between linear body measurement and body weight of beef cattle showed that HG (r = 0.88) and BV (r = 0.97) were significantly (p < 0.05) different compared to BL (r = 0.74) and WH (r = 0.72). The correlation between HG and body weight, and the categorization of cattle breeds showed significantly (p < 0.05) different results. The correlation between BV and body weight of cattle according to breed categories showed results that were not significantly (p > 0.05) different, while age was significantly (p < 0.05). Conclusion: In conclusion, to predict beef cattle body weight, it is necessary to use HG or BV, with breed, sex, and age of cattle as categories. [ABSTRACT FROM AUTHOR]

Context. Providing feed is the largest cost in beef production. Genetic variation exists in feed efficiency traits in young cattle but the genetic associations with feed efficiency traits in cows are poorly understood, but if strong and favourable, they might be used to improve feed efficiency of cows. Aim. To examine the phenotypic and genetic relationships among feed intake, feed efficiency, body composition and cow milk yield measured in young cattle and in cows. Methods. Data on 1783 young Angus, Hereford, Polled Hereford and Shorthorn bulls and heifers, and for 751 of the females as cows, were used to calculate the phenotypic and genetic relationships among feed efficiency traits, body composition and cow milk yield measured postweaning and in mature cows. The young cattle were tested for feed intake and feed efficiency at approximately 9 months of age and the females, after two calvings, were tested again as non-pregnant, non-lactating cows at approximately 4 years of age. Key results. At the postweaning test, the heritability estimates for feed intake, average daily gain, test weight, residual feed intake (RFI), feed conversion ratio, rump fat depth and eye-muscle area were 0.47, 0.32, 0.46, 0.42, 0.28, 0.47 and 0.20 respectively. Corresponding heritability estimates in the cow test were 0.27, 0.35, 0.74, 0.22, 0.30, 0.47 and 0.12. Heritability estimates for 400-day weight, cow 4-year weight and cow milk yield were 0.47, 0.62 and 0.15 respectively. Genetic correlations between traits measured postweaning and the same traits measured in the cow were moderate to high, and for the feed efficiency trait, RFI, was very high (0.95), close to unity. Conclusions. Inclusion of postweaning RFI as a selection criterion in beef cattle breeding can be expected to lead to improvementin cow feed efficiency. Implications. Most breeding decisionsin beef cattle are based on traits measured early in life and forreplacement heifers are made with an aim to improve their productivity and profitability as cows. The strong and favourable associations measured between postweaning RFI and cow RFI mean that feed efficiency measured in young cattle can be used as a selection trait to improve cow feed efficiency. [ABSTRACT FROM AUTHOR]

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Understanding host-microbial interactions in the rumen and its influence on desirable production traits may lead to potential microbiota manipulation or genetic selection for improved cattle feed efficiency. This study investigated the host transcriptome and its correlation with the rumen archaea and bacteria differential abundance of two pure beef cattle breeds (Angus and Charolais) and one composite beef hybrid (Kinsella) divergent for residual feed intake (RFI; low-RFI vs. high-RFI). Using RNA-Sequencing of rumen tissue and 16S rRNA gene amplicon sequencing, differentially expressed genes (FDR ≤ 0.05, |log2(Fold-change) >|2) and differentially abundant (p-value < 0.05) archaea and bacteria amplicon sequence variants (ASV) were determined. Significant correlations between gene expression and ASVs (p-value < 0.05) were determine using Spearman correlation. Interesting associations with muscle contraction and the modulation of the immune system were observed for the genes correlated with bacterial ASVs. Potential functional candidate genes for feed efficiency status were identified for Angus (CCL17, CCR3, and CXCL10), Charolais (KCNK9, GGT1 and IL6), and Kinsella breed (ESR2). The results obtained here provide more insights regarding the applicability of target host and rumen microbial traits for the selection and breeding of more feed efficient beef cattle. [ABSTRACT FROM AUTHOR]

Feed efficiency is a major constraint in the beef industry and has a significant negative correlation with residual feed intake (RFI). RFI is widely used as a measure of feed efficiency in beef cattle and is independent of economic traits such as body weight and average daily gain. However, key traits with commonality or specificity among beef cattle breeds at the same level of RFI have not been reported. Accordingly, the present study hypothesized that signatures associated with feed efficiency would have commonality or specificity in the liver of cattle breeds at the same RFI level. By comparing and integrating liver transcriptome data, we investigated the critical signatures closely associated with RFI in beef cattle using weighted co-expression network analysis, consensus module analysis, functional enrichment analysis and protein network interaction analysis. The results showed that the consensus modules in Angus and Charolais cattle were negatively correlated, and four (turquoise, red, tan, yellow) were significantly positively correlated in Angus liver, while (turquoise, red) were significantly negatively correlated in Charolais liver. These consensus modules were found to be primarily involved in biological processes such as substance metabolism, energy metabolism and gene transcription, which may be one of the possible explanations for the difference in feed efficiency between the two beef breeds. This research also identified five key candidate genes, PLA2G12B, LCAT, MTTP, LCAT, ABCA1 and FADS1, which are closely associated with hepatic lipid metabolism. The present study has identified some modules, genes and pathways that may be the major contributors to the variation in feed efficiency among different cattle breeds, providing a new perspective on the molecular mechanisms of feed efficiency in beef cattle and a research basis for investigating molecular markers associated with feed efficiency in beef cattle. [ABSTRACT FROM AUTHOR]

Simple Summary: Meat producers are trying to increase the efficiency of beef production, with a primary focus on genetic and management strategies for beef cattle breeding. Calf birth weight and growth potential, such as weight at different growth periods, are influenced by a variety of genetic and non-genetic factors. The objective of this study was to evaluate the impact of cows' calving age and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The gender of the calf, cows' age at first calving, cows' number of calvings, and the breeding and calving seasons are frequently used indicators in beef cattle farming. According to the influence of selected factors in this study, it can be concluded that the body weight and growth rates of newborn calves are significantly influenced by the gender of the calf, the number of calvings, as well as calving and breeding seasons, should be taken into account in future animal breeding studies. The objective of this study was to evaluate the impact of cows' calving ages and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The females were purebred Charolais cows that calved between 2019 and 2022. A total of 130 calves (bulls = 76; heifers = 54) were observed during the evaluation. The investigation showed that, based on gender, bulls had a 4.28% higher birth weight than heifers (p < 0.05). The gender of the calves affected their weight, indicating that newborns bulls were significantly heavier. Calf gender affected calf growing performance. Male calves' weight gain was higher than that of females in the time before weaning (210 days). The highest gain of bulls was observed from 211 days to 365 days after birth. The average daily weight of male calves during this period was 6.16% (p < 0.001) higher compared to the period up to 210 days after birth. Heifers had a higher daily weight in the period up to 210 days after birth, and the daily weight gain was 12.9% (p < 0.001) higher in this period compared to the period from 211 to 365 days after birth. We observed a higher weight gain in calves from mothers with a higher number of calvings. Being born from cows with four or more calvings had a significant effect on the weight gain of calves in the period up to 210 days (p < 0.05). In the period up to 210 days, the weight gain of calves born from cows with two calvings was the lowest and was 9.79% lower compared to calves born from cows with four and more calvings (p < 0.05). The best weights were obtained from calves born in the spring and autumn seasons. Calves born in spring, summer, and autumn differed in weight by 0.37 kg. The calves of cows that were inseminated in the autumn season had the highest gain in the period up to 210 days and also from 210 to 365 days (p < 0.05). In our study, significantly higher average birth weight of calves was detected in autumn compared to summer and winter (p < 0.05). Also, the highest gain was found from 211 to 365 days after birth in the summer season, but the difference was only 1.47% (p < 0.05). [ABSTRACT FROM AUTHOR]

Simple Summary: The effect of optimized mating methods for long-term selection has not been studied in cattle breeding. In this study, the linear programming and optimal contribution selection methods on the genetic gain and inbreeding level of beef cattle were explored and evaluated using a simulation strategy. Our results showed that the linear programming method can effectively improve the genetic gain in the population during long-term selection in the breeding process, and the optimal contribution selection method can maintain a balance between improving genetic gain and controlling inbreeding level. Our findings can provide theoretical guidance for the long-term and sustainable genetic gain in breeding populations in farm animals. The optimized selection method can maximize the genetic gain in offspring under the premise of controlling the inbreeding level of the population. At present, genetic gain has been largely improved by using genomic selection in multiple farm animals. However, the design of the optimal selection method and assessment of its effects during long-term selection in beef cattle breeding are yet to be fully explored. In this study, a simulated beef cattle population was constructed, and 15 generations of simulated breeding were carried out using the linear programming breeding strategy (LP) and optimal contribution selection strategy (OCS), respectively. The truncation selection strategy (TS−I and TS−II) was used as the control. During the breeding process, genetic parameters including genetic gain, average kinship coefficient, QTL effect variance, and average observed heterozygosity were calculated and compared across generations. Our results showed that the LP method can significantly improve the genetic gain in the population, especially the genetic performance of the traits with high heritability and the traits with high weight in the breeding process, but the inbreeding level of the population is higher under LP strategy. Although the genetic gain in the population under the OCS strategy is lower than the TS−II strategy, this method can effectively control the inbreeding level of the population. Our findings also suggest that the LP and OCS method can be used as an effective means to improve genetic gain, while the OCS method is a more ideal method to obtain sustainable genetic gain during long-term selection. [ABSTRACT FROM AUTHOR]