Journal of Animal Breeding and Genetics最新文献

{"title":"Thermal Thresholds and Genetic Sensitivity in Barrel Racing Performance of Quarter Horses Across Temperature–Humidity Indices","authors":"Mário Luiz Santana,&nbsp;Annaiza Braga Bignardi","doi":"10.1111/jbg.70056","DOIUrl":"10.1111/jbg.70056","url":null,"abstract":"<p>Heat stress is an increasingly important challenge for the performance and welfare of equine athletes, particularly in competitions conducted across diverse climatic conditions. Understanding the genetic basis of performance responses to increasing thermal load is therefore essential to support robust genetic evaluation and sustainable selection strategies. The objective of this study was to evaluate barrel racing performance of Brazilian Quarter Horses across thermal environments defined by two widely used indicators, the temperature–humidity index (THI) and the wet bulb globe temperature (WBGT), and to estimate genetic parameters associated with baseline performance and environmental sensitivity. A total of 351,993 barrel racing time (BRT) records from 13,960 Quarter Horses were analyzed. Segmented regression models were applied to least squares means to identify heat stress thresholds, while random regression models with polynomial functions were used to estimate covariance components, genetic parameters, and correlations along the thermal gradients. Distinct thermal thresholds were identified for both indices, at THI = 74.7 and WBGT = 23.6, beyond which performance deteriorated more rapidly. Heat stress conditions were observed in 31.15% and 20.71% of barrel racing events according to the THI and WBGT thresholds, respectively, emphasizing the practical relevance of the evaluated thermal gradients. Random regression models assuming continuous thermal variation provided the best overall fit to the data. Additive genetic variance remained relatively stable across thermal environments, whereas permanent environmental and residual variances increased under higher thermal load. Mean heritability under thermoneutral conditions was approximately 0.21 for THI and WBGT, declining modestly to 0.17–0.18 under extreme heat stress. Genetic correlations between thermoneutral and extreme environments remained high for both indices (at approximately 0.97), indicating strong genetic continuity of performance and no substantial reranking of estimated breeding values across the thermal gradient. Overall, THI and WBGT yielded highly consistent results in terms of thresholds, genetic parameters, and selection outcomes. Although WBGT showed slightly greater sensitivity under extreme conditions, THI offered smoother response patterns and clear operational advantages due to its simplicity and ease of calculation. No evidence of substantial genotype-by-environment interaction was detected for BRT. However, the results suggest that incorporating genetic tolerance to heat stress as a complementary selection criterion may help sustain barrel racing performance under increasingly challenging climatic conditions.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 5","pages":"719-733"},"PeriodicalIF":1.9,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148165590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of Genetic Variance and Breeding Values for Infectious Disease Susceptibility From Simulated Longitudinal Data Using Generalized Linear Mixed Models Based on Transmission Dynamics","authors":"A. D. Hulst,&nbsp;R. Pong-Wong,&nbsp;A. Doeschl-Wilson,&nbsp;M. C. M. De Jong,&nbsp;P. Bijma","doi":"10.1111/jbg.70049","DOIUrl":"10.1111/jbg.70049","url":null,"abstract":"<p>Recent theoretical work shows that the potential of genetic selection to reduce the prevalence of infectious diseases is much larger than expected from classical quantitative genetic theory, due to indirect genetic effects that arise in the transmission process. However, to fully benefit from these indirect effects, we need to estimate genetic parameters and breeding values, which requires statistical methods tailored to the transmission process. Here, we evaluate Generalized-Linear-Mixed Models (GLMMs) implemented using software commonly used in animal breeding to estimate genetic parameters and breeding values for susceptibility of hosts to infection, using simulated data of epidemics. Longitudinal records of individuals' infection state provide information on the order of infection, as well as on the exposure dose of non-infected animals. Such information can be harnessed to estimate genetic parameters for susceptibility, and can be included in a GLMM as a so-called offset. Therefore, we used longitudinal records of individual infection state to assess the impact of sampling interval, population structure, infection characteristics, and model formulation on the estimated genetic variance and breeding values for susceptibility. The results show that a GLMM fitted to longitudinal records of individual binary infection state can produce accurate and unbiased estimates of genetic variance, as well as good prediction accuracies of breeding values for susceptibility to an infectious disease. Of the data requirements, the time interval between consecutive observations on individual infection state was the main factor affecting estimation, while group size had a limited effect. The required observation interval depends on the infection and recovery rates of individuals. The GLMM thus seems an accurate and easily implementable model to estimate genetic parameters and breeding values for susceptibility when dense longitudinal records on individual infection status are available.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 5","pages":"639-657"},"PeriodicalIF":1.9,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147640728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic Parameters and Genome-Wide Association Studies for Fertility and Reproduction Traits in U.S. Katahdin Sheep Based on the Single-Step GBLUP Methodology","authors":"Alejandra Toro Ospina,&nbsp;Ronald M. Lewis,&nbsp;Bradley A. Freking,&nbsp;Joan M. Burke,&nbsp;Thomas W. Murphy,&nbsp;Carrie S. Wilson,&nbsp;Luiz F. Brito","doi":"10.1111/jbg.70048","DOIUrl":"10.1111/jbg.70048","url":null,"abstract":"<p>Sheep production contributes to a secure and diverse food and fibre supply in the United States, with growing ethnic diversity strengthening demand. Katahdin is a composite hair-type sheep breed developed in the United States that has become the most popular breed in many regions of the country and the first one to have genomic selection implemented in its breeding program. Therefore, the main objectives of this study were to estimate variance components of reproductive traits, including number of lambs born (NLB), number of lambs weaned (NLW), age at first lambing (AFL), and interval from first to second lambing (LI), in Katahdin sheep using the AIREML method and the single-step Genomic Best Linear Unbiased Prediction (ssGBLUP) approach, and to identify genomic regions and candidate genes associated with these traits. The datasets used consisted of 127,536 animals in the pedigree, phenotypic records of 56,128 parities from 24,067 ewes, and genomic data from 10,032 animals with 30,308 single-nucleotide polymorphisms (SNP) after quality control. Analyses were performed using the BLUPF90 family of programs. We observed low heritability estimates for all studied traits (0.09 ± 0.00 for NLB, 0.08 ± 0.00 for NLW, 0.09 ± 0.01 for AFL, and 0.08 ± 0.01 for LI). The genetic correlations between the traits ranged from 0.17 ± 0.02 (AFL and LI) to 0.79 ± 0.02 (NLB and NLW). All traits were found to be highly polygenic with all 14 significant SNP on eight (OAR) chromosomes (3, 6, 7, 8, 9, 12, 13, and 15) having small effects on the total variability on the traits. These SNP were located near or within 18 candidate genes: four genes associated with NLB (<i>AAK1, GFPT1, SLC23A2,</i> and <i>GDAP1</i>), four with NLW (<i>ARHGAP18, TTLL2, UNC93A,</i> and <i>GPR31</i>), six with AFL (<i>NAP1L5, FAM13A, HS3ST1, CCDC181, NME7,</i> and <i>BLZF1</i>), and four with LI (<i>TAF4, CDH4, CADM1</i>, and <i>SEL1L</i>). These candidate genes have been previously associated with fertility, embryonic development, growth, disease resistance, and climatic adaptation traits. Our findings indicate that fertility and reproduction traits in Katahdin sheep can be improved through direct genetic selection. Genetic improvement for these traits will benefit from genomic selection as more accurate estimates of breeding values for selection candidates can be obtained at a younger age. Although the studied traits are influenced by a complex interplay of genetic and environmental factors, the candidate genes identified enabled a better understanding of the biological mechanisms underlying reproductive performance in Katahdin sheep.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 5","pages":"625-638"},"PeriodicalIF":1.9,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147576674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Better Multi-Breed Genomic Predictions for Tropical Bull Fertility Using a Breed-Adjusted Genomic Relationship Matrix","authors":"Antonio Reverter,&nbsp;Pâmela A. Alexandre,&nbsp;Marina R. S. Fortes,&nbsp;Laercio R. Porto-Neto","doi":"10.1111/jbg.70052","DOIUrl":"10.1111/jbg.70052","url":null,"abstract":"<p>The pressing requirement for agricultural systems to adopt climate change adaptation strategies specifically designed for tropical environments underscores the significance of implementing sustainable bull breeding practices in beef cattle operations. We consider alternative approaches to generation of single- and multi-breed genomic predictions for a population of Brahman (<i>N</i> = 1051), Santa Gertrudis (<i>N</i> = 929) and UltraBlack (<i>N</i> = 844) bulls with genotypes at high-density and phenotypes for scrotal circumference (SCC; mean ± SD = 31.82 ± 4.32 cm), sheath score (SHS; 3.70 ± 1.98) and percent normal sperm (PNS; 63.34% ± 28.22%). We examined five genomic prediction models: three single breed and two multi-breed. The later contained a multi-breed genomic relationship matrix computed without (GRM_u) or adjusting (GRM_a) for breed-specific allele frequencies. Bias, dispersion and accuracy of the genomic predictions across the five models was computed based on cross-validation and using the LR method. The elements of the multi-breed GRM_u revealed anomalies including a multi-modal distribution of diagonal and off-diagonal elements with all diagonal values above one (range: 1.022 to 1.524) and averaging 1.163. Instead, GRM_a values were consistent with expectations: diagonals with a single mass around one (range: 0.844 to 1.391) and off-diagonal values with a single mass around zero. Estimates of heritability (<i>h</i>² ± SE) with the GRM_u model were 0.501 ± 0.037, 0.458 ± 0.037 and 0.362 ± 0.030, for SCC, SHS and PNS, respectively; while <i>h</i>² estimates using GRM_a were comparable for SCC (0.434 ± 0.037), and SHS (0.439 ± 0.038), and possibly lower for PNS (0.226 ± 0.032). Estimates of genetic correlation (<i>r</i>_g) were similar for both models, except for the <i>r</i>_g between SHS and PNS which moved from −0.095 ± 0.119 using GRM_u to −0.298 ± 0.113 using GRM_a. For all traits, the correlation between GEBV from GRM_u and GRM_a was &gt; 0.90, indicating similar ranking of animals regardless of the relationship matrix used. However, a random cross-validation scheme showed that using GRM_a increased GEBV accuracies from 0.550 to 0.571 (or 3.7%) for SCC, from 0.496 to 0.509 (or 2.6%) for SHS and from 0.335 to 0.423 (or 26.2%) for PNS. Multi-breed genomic predictions for tropical bull fertility are feasible alternative to individual single-breed evaluation systems. Furthermore, the computational effort required to adjust the genomic relationship matrix for breed-specific allele frequencies is justified by the significant improvement in prediction accuracy, ultimately enhancing the selection of bulls in tropical environments. Collectively these results enable very early in-life selection for bull fertility traits, supporting genetic improvement strategies currently taking place within tropical beef production systems in northern Australia.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 5","pages":"679-690"},"PeriodicalIF":1.9,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147789332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phenotypic Responses to Selection in Ross 308 Broiler Breeders: Long-Term Growth Assessed With Nonlinear Models Across Four Generations","authors":"Lajan Salahaldin Ahmed,&nbsp;Haval Ismail Aziz","doi":"10.1111/jbg.70053","DOIUrl":"10.1111/jbg.70053","url":null,"abstract":"<div>\u0000 \u0000 <p>Phenotypic responses to selection in growth performance of Ross 308 broiler breeders were evaluated using longitudinal body weight records from hatch to 64 weeks across four successive generations (G1–G4). The effects of generation, sex, and their interaction on body weight were examined, and sex-specific growth trajectories were modelled using eight nonlinear growth functions (Gompertz, Richards, Logistic, Brody, von Bertalanffy, Weibull, Hossfeld, and López). Generation and sex exerted highly significant effects on body weight across most ages (<i>p</i> ≤ 0.0001), with males consistently heavier than females and sexual dimorphism becoming evident after 4 weeks of age. At 60 weeks, fourth-generation birds exhibited higher body weights than first-generation birds (males: 5036.5 vs. 4744.3 g; females: 4152.2 vs. 3858.3 g), indicating progressive phenotypic improvement across generations. A significant generation × sex interaction (<i>p</i> ≤ 0.05) indicated that the magnitude of sexual dimorphism varied among generations. Model performance was evaluated using the coefficient of determination (<i>R</i>²), adjusted <i>R</i>² (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>R</mi>\u0000 <mi>adj</mi>\u0000 <mn>2</mn>\u0000 </msubsup>\u0000 </mrow>\u0000 </semantics></math>), mean square error (MSE), root mean square error (RMSE), Akaike's Information Criterion (AIC), and Bayesian Information Criterion (BIC). All nonlinear models adequately described the growth patterns of Ross 308 broiler breeders. Among them, the Gompertz function generally provided the best fit across generations and sexes (<i>R</i>² = 0.9978–0.999; <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>R</mi>\u0000 <mi>adj</mi>\u0000 <mn>2</mn>\u0000 </msubsup>\u0000 </mrow>\u0000 </semantics></math> = 0.9974–0.999; MSE = 1521.5–1988.5; RMSE = 39.03–44.59), while the Richards model effectively captured sex- and generation-specific variation in growth trajectories. Inflection point weights ranged from 1819.5 to 2012.5 g in males and from 1433.7 to 1573.4 g in females. Predicted values were closely aligned with observed data across models, indicating good descriptive performance of the fitted functions. These findings highlight consistent phenotypic improvement in growth traits across generations and demonstrate that the Gompertz model provides a practical and robust framework for describing and monitoring growth dynamics in broiler breeder populations, supporting its use in selection and management decisions.</p>\u0000 </div>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 5","pages":"691-704"},"PeriodicalIF":1.9,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147846400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating Selection Strategies Based on Inbreeding Load via Simulation.","authors":"Simona Antonios, Jana Obšteter, Ivan Pocrnic, Gregor Gorjanc, Silvia T Rodríguez-Ramilo, Zulma G Vitezica","doi":"10.1111/jbg.70066","DOIUrl":"https://doi.org/10.1111/jbg.70066","url":null,"abstract":"<p><p>Inbreeding load is the fraction of the mutation load that is due to recessive action of mutations. This load is only expressed in individual's inbred offspring. As such, inbreeding load contributes to genetic heterogeneity among individuals and can thus be used as a criterion of selection. Future parents could be selected based on their estimated breeding values and their estimated inbreeding load. Here, we evaluated the effectiveness of selection strategies involving inbreeding load in a dairy sheep breeding scheme. We evaluated seven strategies with a stochastic simulation across 15 generations of genetic evaluation and selection. The strategies differed in the criteria of selection (only estimated breeding values, only estimated inbreeding load, both or random) and mate strategies minimising inbreeding load, adjusting estimated breeding values by the expected future inbreeding or random. The strategies were compared in terms of genetic gain, pedigree-based inbreeding coefficients, rate of inbreeding, effective population size, inbreeding depression estimates, and accuracy of selection. Results showed that among the seven strategies, there was no significant difference between the five in which selection was based on estimated breeding values over the 15 years of the simulated dairy sheep breeding scheme. As expected, selection only on the estimated inbreeding load and the random selection and random mating strategy had significantly lower genetic gain than the five strategies in which selection was based on estimated breeding values. To conclude, selecting animals using estimated inbreeding load is feasible. However, the magnitude of inbreeding load effects and its accuracy did not show a clear practical interest. Furthermore, the benefit of using inbreeding load in mate allocation strategies was negligible.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148702328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Economic Benefit of Genetic Progress in Five Wool Sheep Breeds of Argentina","authors":"Joaquín Pablo Mueller,&nbsp;Nicolás Giovannini,&nbsp;Juan Mauricio Álvarez,&nbsp;Pedro Alejandro Vozzi,&nbsp;Daniel Omar Maizon,&nbsp;Emilio Rivera,&nbsp;Francisco Milicevic,&nbsp;María Virginia Sturzenbaum,&nbsp;Alan Maxs Pardo","doi":"10.1111/jbg.70040","DOIUrl":"10.1111/jbg.70040","url":null,"abstract":"<div>\u0000 \u0000 <p>The economic benefits of genetic improvement were estimated based on genetic trends observed for economically important traits in stud herds participating in Argentina's genetic evaluation scheme. The analysis included Horned Merino, Polled Merino, Dohne Merino, Corriedale and Polwarth sheep born between 2014 and 2023. This benefit was calculated as the difference between the additional income generated by the increased value of meat and wool in multiplier and commercial herds, and the costs associated with genetic improvement at the stud tier and additional cost of improved rams at multiplier and commercial tiers. The benefits of 10 years of genetic improvement and their residual effect for another 10 years were computed, updating the annual results with a discount rate of 5%. The benefit obtained in the five breeds reached USD 4.95 million considering only breeding program costs at the stud tier. Including additional ram buying costs, the benefit reached USD 3.75 million, the difference being captured by the ram selling tiers. At the breed level (ignoring ram buying costs) the return to investment (ROI) amounted to 33.6. At multiplier and commercial herd tiers (including ram buying costs) the income to cost ratios were 5.5 and 4.0, respectively. The Corriedale breed was responsible for 39% of the total benefit. Altogether, genetic improvement in the stud tier reached 1.47 million lambs annually or about 54% of the five wool sheep populations of the country. Thus, conventional genetic improvement efforts of economically important traits of wool sheep breeds proved to have been highly profitable.</p>\u0000 </div>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 4","pages":"524-534"},"PeriodicalIF":1.9,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145953954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of Cluster Analysis for Identifying Metafounders","authors":"Christine Anglhuber,&nbsp;Christian Edel,&nbsp;Eduardo C. G. Pimentel,&nbsp;Reiner Emmerling,&nbsp;Kay-Uwe Götz,&nbsp;Georg Thaller","doi":"10.1111/jbg.70039","DOIUrl":"10.1111/jbg.70039","url":null,"abstract":"&lt;p&gt;In the metafounder approach, the relationship matrix of metafounders, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;Γ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; is used to transfer information on relationships between pedigree founders into the numerator relationship matrix &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, creating matrix &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mi&gt;Γ&lt;/mi&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. Commonly metafounders are defined based on the available information of the animal (e.g., country, sex, breed) similar to unknown parent groups (UPG). This limits the ability of metafounders to correctly reflect the population structure. In Single-Step Models, hidden stratification in the population may cause inconsistencies between matrix &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and the genomic relationship matrix &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;G&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; when they are combined into matrix &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. Reliable information on the true structure in a population can be obtained from genotypes. In this study, we investigate an approach to transfer information on population structure from the genotyped animals to the ungenotyped ancestors. We used an unsupervised clustering approach to assign pedigree founders to metafounders and performed Single-Step genomic evaluation for an increasing number of metafounders (nMF) assumed. The optimum nMF to model was determined by harmonising the trend in inbreeding in &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;G&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mi&gt;Γ&lt;/mi&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and by monitoring of elements in &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;Γ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. A semi-stochastic simulation based on real genotypes from Fleckvieh was used to investigate two scenarios: a trait with a strong genetic trend and a trait with","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 4","pages":"535-559"},"PeriodicalIF":1.9,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146031630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contribution of Fat Adjustment to Residual Feed Intake Estimation in Beef Cattle","authors":"Larissa Bordin Temp,&nbsp;Letícia Pereira,&nbsp;Marcos Jun-Iti Yokoo,&nbsp;Cintia Righetti Marcondes,&nbsp;Roberto D. Sainz,&nbsp;Fernando Bussiman,&nbsp;Jorge Hidalgo,&nbsp;Daniela Lourenco,&nbsp;Fernando Baldi","doi":"10.1111/jbg.70045","DOIUrl":"10.1111/jbg.70045","url":null,"abstract":"<p>Including fat thickness as a covariate in the regression model used to calculate residual feed intake (RFI) could help preserve carcass quality traits, such as marbling, flavour and juiciness, by accounting for variation in fat deposition. This study aimed to: (1) investigate the benefits of adjusting RFI for rump fat thickness (RFT); (2) estimate variance components and genetic correlations between RFI—calculated with (RFI_F) and without (RFI_W) adjustment for RFT—and growth, reproduction and carcass traits using genomic information in beef cattle; and (3) compute accuracy, bias and dispersion of RFI_F and RFI_W genomic breeding values predicted using single-step GBLUP (ssGBLUP). We hypothesised that adjusting for RFT would account for a small proportion of RFI variability, and that genetic parameter estimates would support more balanced selection decisions. Phenotypic records were collected from 9094 Nellore animals (3253 females and 5952 males) over 14 feed efficiency tests conducted from 2011 to 2024. The pedigree included 17,407 animals, of which 5812 were genotyped. Linear and threshold animal models were applied for continuous and categorical traits, respectively. Heritability estimates were low for RFI_W (0.17) and RFI_F (0.16), with a strong genetic correlation between them (0.98), and a weak genetic correlation between RFI_W and RFT (0.15). Spearman correlations between RFI_F and RFI_W breeding values were high: 0.98 in females and 0.95 in males. Genetic correlations of RFI_W and RFI_F with growth, reproduction and carcass traits ranged from −0.33 to 0.35. Prediction accuracy was similar for RFI_F (0.43) and RFI_W (0.44), whereas bias (0.00 for RFI_w and 0.00 for RFI_F) and dispersion (0.05 for RFI_w and 0.03 for RFI_F) showed minor differences. Although RFI_F captured slightly more genetic variability, the impact was minimal and no differences were observed between RFI_F and RFI_W. The genetic correlations between RFI and traits related to growth, reproduction and carcass were close to zero to moderate, indicating that selection for RFI is unlikely to negatively impact these other traits. However, it is essential to consider the full set of traits in the selection process to avoid potential drawbacks to the overall genetic progress of the herd.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 4","pages":"602-612"},"PeriodicalIF":1.9,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147277770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reproductive Success in Beef Cows: Bayesian Evaluation of Genotype and Herbage Allowance Under Grazing Conditions","authors":"Rodrigo Vivián,&nbsp;Raquel Pérez-Clariget,&nbsp;Ana Carolina Espasandín","doi":"10.1111/jbg.70044","DOIUrl":"10.1111/jbg.70044","url":null,"abstract":"<div>\u0000 \u0000 <p>Reproductive losses from breeding to weaning jeopardise productivity and sustainability in extensive beef cattle systems. This study evaluated the effects of cow genotype (purebred vs. crossbred) and herbage allowance (high vs. low) on reproductive success across three biologically relevant periods: (I) breeding to pregnancy diagnosis, (II) pregnancy diagnosis to calving and (III) calving to weaning. A total of 1069 reproductive events from Hereford, Angus and reciprocal crossbred cows were analysed between 2007 and 2022 under native pasture conditions in Uruguay. Bayesian generalised linear mixed models were applied to estimate posterior probabilities of reproductive success, accounting for repeated measures and individual cow effects. Crossbred cows consistently exhibited higher probabilities of success than purebreds across all reproductive periods. Under low herbage allowance, the crossbred advantage was most pronounced in Period III (Δ = 0.22; <i>P</i> (Δ &gt; 0) = 1.00), followed by Periods I and II (Δ ≈ 0.13; <i>P</i> (Δ &gt; 0) ≥ 0.99), indicating a moderate genotype × nutrition interaction. High herbage allowance improved outcomes for all cows, particularly during the calving-to-weaning stage. Cumulative probabilities (weaned/served) were approximately 0.43 for purebred–low, 0.63 for purebred–high and 0.78 for crossbreds under both herbage levels, corresponding to 30–35 more calves weaned per 100 cows served when using crossbred females. These results demonstrate that both crossbreeding and adequate herbage allowance enhance reproductive performance under grazing conditions and offer robust, cost-effective strategies to improve efficiency and resilience in extensive beef production systems.</p>\u0000 </div>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 4","pages":"595-601"},"PeriodicalIF":1.9,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147277779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}