Journal of Animal Breeding and Genetics最新文献

{"title":"Population Differentiation and Polygenic Selection in the Finnish Ayrshire Cows Selected on Genomic Information","authors":"Katri Sarviaho,&nbsp;Minna Koivula,&nbsp;Terhi Iso-Touru,&nbsp;Pekka Uimari,&nbsp;Katja Hänninen","doi":"10.1111/jbg.70061","DOIUrl":"10.1111/jbg.70061","url":null,"abstract":"<p>The Finnish Ayrshire cattle belong to the Nordic Red breeds. The basis of selection in Nordic Red breeds shifted from traditional pedigree-based breeding values to genomic breeding values between 2011 and 2014. Joint genetic evaluation and admixture among the Nordic Red breeds have led to the formation of a composite Nordic Red population; consequently, contemporary Finnish Ayrshire represents an admixed population. We identified recent selection signatures in the Finnish Ayrshire genome using two complementary approaches: the Hudson estimator of Wright's fixation index (F_ST) and generation proxy selection mapping (GPSM). Hudson F_ST quantifies population-differentiation between groups, whereas GPSM detects selection signatures within a single population by regressing birth year on SNP genotypes. The aim of this study was to identify temporal allele frequency changes in SNPs consistent with selection during the genomic era and to evaluate their associations with milk production and fertility traits in Finnish Ayrshire. Genotypes were available for 64,160 cows across 46,914 SNPs, and phenotypic data on milk production and fertility traits were available for 49,417 genotyped individuals. Based on Hudson F_ST, 56 SNPs showed genetic differentiation between cows selected using pedigree-based and genomic information. In addition, 54 SNPs exhibited temporal allele frequency changes consistent with selection according to GPSM. Overall, 11 SNPs were identified by both methods. Of the 54 SNPs, thirteen were associated with the interval from first to last insemination in Finnish Ayrshire heifers. These results suggest that a substantial proportion of SNPs exhibiting temporal allele frequency changes during genomic selection are associated with heifer fertility.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 6","pages":"774-783"},"PeriodicalIF":1.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148383054","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":"A Comprehensive Analysis of Y-Chromosome Lineages Identifies Paternal Founder Effects in European, African, and Asian Cattle","authors":"Huixuan Yan,&nbsp;Xiying Quan,&nbsp;Xuanyu Li,&nbsp;Shuang Liu,&nbsp;SuoLang QuJi,&nbsp;CiRen LuoBu,&nbsp;Zhenyu Lei,&nbsp;Fuqiang Li,&nbsp;Weidong Ma,&nbsp;Xingshan Qi,&nbsp;Johannes A. Lenstra,&nbsp;Xiaoting Xia,&nbsp;Rende Song,&nbsp;Yun Ma,&nbsp;Chuzhao Lei,&nbsp;Ningbo Chen","doi":"10.1111/jbg.70062","DOIUrl":"10.1111/jbg.70062","url":null,"abstract":"<div>\u0000 \u0000 <p>We studied the worldwide differentiation of Y-chromosomal haplotypes of cattle in order to clarify their origin and migrations. Previous studies of Y-chromosomal single-nucleotide polymorphisms (Y-SNPs) have defined five Y-chromosomal haplogroups and 10 sub-haplogroups of global cattle. In this study, we collected genomic data for 560 male cattle from Europe, America, Africa and Asia, including 71 Central Chinese cattle (CCC) of mixed taurindicine ancestry. We identified 1418 Y-SNPs, which defined 11 Y-chromosomal sub-haplogroups. Their geographic distributions indicate two paternal founder effects in Europe and Africa, respectively, whereas two other founder effects occurred relatively recently within China in the CCC (Y2B haplogroup) and the South Chinese indicine (Y3A3 sub-haplogroup). This suggests that the environmental adaptation of Chinese cattle was accompanied by consequential paternal founder effects due to population bottlenecks, which is relevant for the conservation and management of the Chinese cattle breeds.</p>\u0000 </div>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 6","pages":"784-789"},"PeriodicalIF":1.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148399934","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":"Quantifying Dominance Variance to Enhance Genetic Evaluation and Prediction of Pre-Weaning Growth Traits in Dairy Goats","authors":"Jamshid Ehsaninia,&nbsp;Alireza Bagheripour","doi":"10.1111/jbg.70063","DOIUrl":"10.1111/jbg.70063","url":null,"abstract":"<div>\u0000 \u0000 <p>Dominance genetic effects, despite their recognized role in complex traits, are rarely included in livestock genetic evaluations. Using extensive phenotypic and pedigree data from 7537 dairy goat kids born between 2016 and 2023, we assessed the contribution of dominance variance to early growth traits through single-trait animal models fitted by the AI-REML algorithm in WOMBAT. The models combined additive, dominance, maternal genetic and maternal permanent environmental effects, and were evaluated using Akaike's Information Criterion (AIC), mean squared error (MSE) and Pearson's correlation between observed and predicted phenotypes (<i>r</i>(<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>y</mi>\u0000 </mrow>\u0000 </semantics></math>,<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mover>\u0000 <mi>y</mi>\u0000 <mo>̂</mo>\u0000 </mover>\u0000 </mrow>\u0000 </semantics></math>)). Incorporating dominance variance consistently improved model fit and predictive ability across traits, reducing residual variance by 13%–59% and increasing the accuracy of additive breeding values by up to 59%, without substantially altering the ranking of top animals. On average, dominance variance explained 30% of phenotypic variation, corresponding to 76% of the additive genetic variance. Dominance heritabilities for birth weight (BWT), weaning weight (WWT) and average daily gain (ADG) were 0.48 ± 0.06, 0.12 ± 0.03 and 0.32 ± 0.02, respectively, whereas additive heritabilities were lower (0.05–0.10). Genetic correlations differed notably between additive (0.59–0.66) and dominance (−0.33–0.41) components, highlighting the distinct contribution of non-additive effects. This study provides one of the first large-scale evaluations of dominance variance in dairy goats under commercial conditions. The results demonstrate that ignoring dominance can lead to underestimation of genetic variance and reduced predictive accuracy, underscoring the importance of modelling dominance effects in small ruminant breeding programs. These findings extend beyond a single breed, offering valuable implications for genetic evaluation strategies in dairy goats and other small ruminants.</p>\u0000 </div>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 6","pages":"790-806"},"PeriodicalIF":1.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148426535","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":"Genetic Associations of Functional Longevity With Sexual Precocity and Growth Traits in Nellore Beef Cattle","authors":"Dalila Ribeiro dos Santos,&nbsp;Gabriele de Souza Silva Fernandes,&nbsp;Arione Augusti Boligon,&nbsp;Mário Luiz Santana,&nbsp;Gilberto Romeiro de Oliveira Menezes,&nbsp;Denise Rocha Ayres,&nbsp;Annaiza Braga Bignardi,&nbsp;Rodrigo Junqueira Pereira","doi":"10.1111/jbg.70065","DOIUrl":"10.1111/jbg.70065","url":null,"abstract":"<p>Functional longevity (FL) is a complex trait that integrates many attributes directly contributing to the successful retention and productivity of a cow within the herd. Consequently, improving FL in beef cattle increases herd profitability. This study aimed to estimate the genetic associations between two alternative FL definitions and traits related to sexual precocity and growth in Nellore cattle from data comprising 2,607,400 calving records. Two FL traits, evaluated from 27 to 135 months of age, were analysed using random regression animal models: the ability to remain in the herd, evaluated as a binary trait (FLSTAY), and the cumulative number of calvings up to the predefined standard ages (FLNC). Approximate genetic correlations among FL measures, age at first calving (AFC), weaning weight (WW), and yearling weight (YW) were estimated using Calo's method based on the estimated breeding values (EBVs) of individuals with an accuracy of at least 0.60 for both traits. Heritability estimates for FLNC ranged from 0.020 (95% highest posterior density [HPD]: 0.018 to 0.022) to 0.075 (95% HPD: 0.067 to 0.084) and were consistently higher than those for FLSTAY, which ranged from 0.004 (95% HPD: 0.004 to 0.005) to 0.045 (95% HPD: 0.039 to 0.051) across all evaluated ages. The approximate genetic correlations between FLSTAY and FLNC were positive and high (≈0.90) throughout the productive lifespan. Approximate genetic correlations between AFC and both FL measures were favourable, exhibiting a high magnitude at 27 months of age (≈−0.75) and gradually decreasing to values around −0.25. Approximate genetic correlations between WW (direct effect) and FL traits were favourable, starting high at 27 months (≈0.58) and gradually decreasing to 0.06 for FLNC and 0.15 for FLSTAY at older ages. Approximate genetic correlation estimates between WW (maternal effect) and both FLSTAY and FLNC were also favourable (≈0.20) across ages. YW followed a similar trend, showing favourable genetic correlations of ≈0.28 at 27 months that decreased to ≈0.10 near 75 months. Both FL traits exhibit sufficient genetic variability for long-term selection. However, FLNC is recommended over FLSTAY as a selection criterion due to its consistently higher heritability. The favourable genetic associations demonstrate no antagonism between functional longevity and standard growth or sexual precocity traits, supporting the implementation of FLNC as a feasible alternative to traditional single-measure stayability in Nellore breeding programs.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 6","pages":"821-833"},"PeriodicalIF":1.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148671357","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":"Evaluating the Predictive Value of Estimated Breeding Values of Piétrain Sires for Uniformity and Survival in Their Crossbred Progeny","authors":"Katrijn Hooyberghs,&nbsp;Sophie Goethals,&nbsp;Roel Meyermans,&nbsp;Léa Chapard,&nbsp;Jaro De Kort,&nbsp;Inne Patteet,&nbsp;Sam Millet,&nbsp;Steven Janssens,&nbsp;Nadine Buys,&nbsp;Wim Gorssen","doi":"10.1111/jbg.70058","DOIUrl":"10.1111/jbg.70058","url":null,"abstract":"<p>High litter sizes in pigs are associated with lower birth weights and increased within-litter variation, which poses challenges to pig farming. Improving piglet uniformity and survival via genetic selection of terminal boars could be a strategy to enhance these traits. This study evaluated how well estimated breeding values for uniformity and survival of terminal Piétrain sires predict within-litter uniformity and mortality rates in their crossbred offspring from birth until slaughter. We selected six Piétrain boars with contrasting estimated breeding values for uniformity and survival (3 high vs. 3 low) and mated these with 93 hybrid sows, which produced 1421 liveborn piglets. Moderate correlations were observed between crossbred piglets' within-litter uniformity and the paternal estimated breeding values (<i>r</i> = 0.17 to 0.28), indicating that the used estimated breeding values for uniformity and survival of terminal sires have a low predictive value for within-litter uniformity. Nonetheless, significant associations were found between these estimated breeding values and specific survival- and uniformity-related traits, such as pre-weaning survival and uniformity of growth, supporting their potential for selection. When analysing piglets' weights over time, low correlations were observed between the coefficient of variation at birth and later in life (<i>r</i> = 0.05 to 0.24). On the other hand, moderate to high correlations were found between coefficients of variation at weaning and later in life (<i>r</i> = 0.34 to 0.88), indicating stability of the within-litter body weight uniformity after weaning. These findings suggest that pre- and post-weaning within-litter body weight uniformity should be considered as two distinct traits.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 6","pages":"746-761"},"PeriodicalIF":1.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70058","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148220829","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 Evaluation for Functional Longevity in Nellore Cattle","authors":"Gabriele de Souza Silva Fernandes,&nbsp;Dalila Ribeiro dos Santos,&nbsp;Arione Augusti Boligon,&nbsp;Mário Luiz Santana,&nbsp;Gilberto Romeiro de Oliveira Menezes,&nbsp;Denise Rocha Ayres,&nbsp;Annaiza Braga Bignardi,&nbsp;Rodrigo Junqueira Pereira","doi":"10.1111/jbg.70067","DOIUrl":"10.1111/jbg.70067","url":null,"abstract":"<p>Stayability (STAY) presents limitations in capturing genetic variability among animals with varying calving records up to 76 months of age. Furthermore, because STAY is measured late in life (typically at 6 years of age), it inherently prolongs generation intervals. To address this limitation, we evaluated an alternative approach using random regression models, which incorporate multiple phenotypes recorded throughout an animal's lifespan to generate predictive curves for breeding values. Using calving records from 179,001 Nellore cows, we compared two phenotypic expressions of longevity and aimed to identify the optimal random regression model for predicting breeding values. Ten specific ages were defined for functional longevity expressed as stayability (FLSTAY). At each age, a binary phenotype (1 or 0) was assigned based on whether the cow remained in the herd. Alternatively, for functional longevity associated with the number of calvings (FLNC), the cumulative number of calvings recorded up to each specific age was calculated. Models fitting Legendre orthogonal polynomials ranging from linear to cubic degrees were compared. The cubic polynomial proved most suitable for modelling FLSTAY, whereas the quadratic polynomial provided the best fit for FLNC. Predictive ability metrics of estimated breeding values for FLNC were superior to those for FLSTAY. Heritability estimates for FLNC (0.025–0.074) were consistently higher than those for FLSTAY (0.004–0.045). Similarly, genetic correlations across ages were generally stronger for FLNC, reaching 0.88 between 39 and 75 months (the traditional age for selection). These findings suggest the feasibility of applying random regression models to FLNC, allowing its use as an early selection strategy to improve functional longevity.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":"143 6","pages":"834-845"},"PeriodicalIF":1.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jbg.70067","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148702390","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":"Heritability of Productive, Reproductive and Carcass Traits in Pure-Bred and Cross-Bred Pigs: A Systematic Review and Meta-Analysis.","authors":"Wilber Hernández-Montiel, Amada I Osorio-Terán, Víctor M Meza-Villalvazo, Adolfo Amador-Mendoza, José Abad-Zavaleta, Nicolás Valenzuela-Jiménez, Mario Alberto Martínez-Núñez","doi":"10.1111/jbg.70077","DOIUrl":"https://doi.org/10.1111/jbg.70077","url":null,"abstract":"<p><p>Heritability (h²) is a key parameter in animal breeding, but its magnitude and consistency across pure-bred (PB) and cross-bred (CB) pig populations remain poorly understood. This study aimed to compare heritability estimates between PB and CB populations for economically relevant traits through a systematic review and meta-analysis. A total of 28 studies (75 independent h² estimates) were identified through searches in PubMed, Mendeley, Springer, ScienceDirect and Google Scholar (2000-2024). Multilevel random-effects models with logit transformation were applied. Traits were grouped into reproductive, growth, conformation and carcass categories. Reproductive traits showed low heritability (e.g., litter size: 0.06 in PB and 0.20 in CB; number born alive [NBA]: 0.07 in CB), whereas growth and carcass traits exhibited moderate values (e.g., average daily gain: 0.21 in PB and 0.31 in CB; intramuscular fat: 0.31 in PB and 0.29 in CB; pH: 0.23-0.26). Meta-regression did not detect a significant effect of population type (β = 0.124, p = 0.630), whereas studies accounting for non-additive genetic effects showed significantly different heritability estimates (QM = 4.35, p = 0.037), and high heterogeneity was observed across traits (I² > 90%). These results indicate that cross-breeding does not systematically increase additive heritability. Instead, differences depend on trait type, likely reflecting differences in genetic architecture and the relative contribution of additive and non-additive genetic effects. Overall, these findings highlight the importance of population-specific genetic evaluations and context-dependent breeding strategies in pig production, supporting the complementary interpretation of heritability and pure-bred-cross-bred genetic correlation (rPC) within Combined Cross-bred and Pure-bred Selection (CCPS) programmes.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148992399","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":"Genomic Insights Into Heterosis: Dominance or Additive × Additive Interaction?","authors":"A Rogberg-Muñoz, J P Steibel, J W R Martini, S Munilla, N S Forneris, C García-Baccino, C W Ernst, R O Bates, G Giovambattista, R J C Cantet","doi":"10.1111/jbg.70075","DOIUrl":"https://doi.org/10.1111/jbg.70075","url":null,"abstract":"<p><p>Heterosis was documented in the 18th century, but its biological basis has been debated since. The theoretical framework proposed by Hill, and adapted by Lynch, is based on two central parameters: admixed composition (S), and the heterozygosity (H). Using genomic information, it is now possible to estimate independently the individual realized S_i and H_i. In this research, a methodology for estimating the contribution of dominance and additive × additive effects to heterosis is proposed. This approach would be especially relevant in cases where there is insufficient phenotypic information available, or an adequate genetic group experimental design, common in humans, wild species and other admixed populations. We also provide theoretical arguments highlighting the enhanced precision of the estimations of heterosis parameters through this method. Furthermore, we exemplify this procedure by analysing data from an experimental F₂ pig population, which was initially designed for QTL mapping. Notably, all animals in this population were genotyped (including F₁ and parental breeds), but phenotypic information was only available for F₂ individuals and included 13 traits related to growth, fat deposition, carcass characteristics and meat quality. Significant additive effects (p < 0.05) were detected for longissimus muscle area and carcass temperature, suggesting complementary additive effects for these traits. Significant dominance and additive × additive effects were also detected for birth weight and carcass length, respectively (p < 0.05), indicating that heterosis for these traits is primarily attributable to dominance and additive × additive interactions. These results demonstrate that the proposed methodology can successfully estimate the genetic components underlying heterosis and underscores the utility of this approach in situations where we possess genomic data but limited phenotypic data.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148946137","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":"Spectral Transforms as a Tool to Optimize Digital Phenotyping in Biological Images.","authors":"Joseane Padilha, Jose Victor Vieira Isola, Elsio Antonio Pereira de Figueiredo","doi":"10.1111/jbg.70076","DOIUrl":"https://doi.org/10.1111/jbg.70076","url":null,"abstract":"<p><p>Modern livestock breeding has mastered genotyping. Genome-wide association studies, genomic selection, and SNP arrays enable genetic merit prediction at lower cost. However, phenotyping remains the bottleneck, as manual measurement is slow, expensive, subjective, and unable to capture spatial or temporal trait organization. Digital phenotyping via artificial intelligence could resolve this, but deep learning requires thousands of labelled examples, impractical when phenotyping cost itself limits datasets to hundreds of individuals. This creates a paradox: AI could accelerate phenotyping but requires large numbers of samples to train the models. Here, we demonstrate that integrating computer vision with machine learning offers sample-efficient digital phenotyping using eggshell colour as a model system. Rather than learning features from scratch (deep learning), we engineer physically motivated features via Wavelet transforms that decompose images into multi-scale spatial components. Wavelet features captured 14.2 percentage points more variance (R² = 0.976 vs. 0.834, p < 0.001) than standard colorimetry, with 50% better sample efficiency (achieving at n = 60 what colorimetry required n = 120). Variance decomposition revealed 77% of discriminative capacity derives from spatial patterns (bands, spots, gradients) invisible to scalar averages. Additionally, we identified \"cryptic phenotypes\" (3.3%) where spatial patterns contradicted average colour, cases where colorimeters failed but Wavelets succeeded. The underlying principle-that spatial decomposition can recover organizational information lost by scalar averaging-may be applicable to other traits with spatial or temporal structure, such as marbling, dermatitis, or pigmentation rhythms, although whether comparable performance gains would be observed remains to be tested empirically. Hence, for breeding programs implementing genomic selection, computer vision-based digital phenotyping captures complex trait variation without massive training datasets, addressing the bottleneck that increasingly limits genetic progress as genotyping becomes trivial.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148921610","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":"Exploring the Genetic Variation of Fleece and Crutch Shedding in Sheep, Recorded at Different Times Within and Across Age Classes.","authors":"Erin G Smith, John R Keiller, Matt P Kelly, Daniel J Brown, Samuel F Walkom","doi":"10.1111/jbg.70074","DOIUrl":"https://doi.org/10.1111/jbg.70074","url":null,"abstract":"<p><p>The global value of wool from coarse woolled sheep continues to decline, prompting producers to seek alternatives that reduce or eliminate the need for shearing. Several sheep breeds naturally shed their fleece in response to photoperiod, and these breeds are being crossed with populations that have high genetic merit for traits such as reproduction, growth and carcase quality. Breeding programmes globally are now aiming to improve the shedding ability of these crosses. To achieve this, producers need to understand the optimal timing and age to record shedding in their flocks in order to maximise genetic progress. This study aimed to investigate the genetic merit of visually scored fleece and crutch shedding traits across different ages and throughout the shedding season, which spans from the winter solstice (June) to the summer solstice (December) when fleece begins to regrow, in Australian maternal composites. Shedding was assessed as a visually scored trait (1 = completely shed, 5 = fully woolly) over 10 years from three age classes: lambs, yearlings and adults. Records were grouped into three periods within the shedding season: early (June-September), peak (October-December) and late (January-April). Variance components and heritabilities were estimated using univariate and bivariate single-step animal models. The genetic correlation between fleece and crutch shedding was estimated within season and across ages, as well as between fleece and crutch shedding. Results showed that fleece and crutch shedding heritabilities were highest during the peak and late periods (0.56-0.66 for fleece; 0.38-0.57 for crutch) and lower during the early period for fleece shedding (~0.40). Genetic correlations between adjacent records within age stages were strong (Peak-Late or Early-Peak, ranging between 0.78 and 0.91) but slightly lower for records taken further apart (Early-Late ~0.74). Correlations between yearling and adult traits were more similar (range 0.62 to 0.91), while the correlations between lamb and adult records were lower (0.57 to 0.78). Fleece and crutch shedding recorded within the same period were highly correlated (> 0.75), and trait repeatabilities within age classes ranged from 0.41 to 0.60. These results suggest that scoring shedding during the peak or late periods captures the greatest phenotypic expression and genetic variation. Selection based solely on lamb shedding may not accurately predict adult performance, especially for breeding programmes where complete shedding in adults is the objective.</p>","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148901669","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}