Publications by authors named "Curtis P Van Tassell"

Calf diarrhea (DIAR) and respiratory illnesses (RESP) are leading causes of calf mortality. This study aimed to develop a comprehensive US national genomic evaluation for these important calf health traits using producer-recorded data from the National Cooperator Database. Analyses included 207,602 calf records for DIAR (age 3 to 60 d) and 681,741 records for RESP (age 3 to 365 d) from all breeds (97.

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Cameroon Blackbelly sheep are a domestic breed of hair sheep from West/Central Africa. They are popular with small-holder farmers in Cameroon as they are highly resilient to local environmental challenges and are prolific a-seasonal breeders. The aim of this study was to characterise the genetics of Cameroon Blackbelly sheep in relation to global sheep populations and to investigate their relationship to Caribbean hair sheep.

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DNA methylation is crucial in gene expression regulation and tissue differentiation in livestock. However, genome-wide methylation patterns among tissues remain underexplored in cattle, one of the world's most important farm animals. This study investigates sex- and tissue-specific DNA methylation in cattle using CpG site methylation data generated by an Infinium DNA Methylation array (HorvathMammalMethyl-Chip40) across seven tissues.

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Introduction: Most SV studies in livestock rely on short-read sequencing, posing challenges in accurately characterizing large genomic variants due to their limited read length.

Objectives: Our goal is to reveal structural variation and novel sequences specific to Holstein and Jersey cattle breeds using long-read and pan-genome analyses.

Methods: We sequenced 20 Holsteins and 8 Jersey cattle using PacBio HiFi to 20×, and integrated five read-based and one assembly-based SV caller to determine SVs.

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Indian desi cattle, known for their adaptability and phenotypic diversity, represent a valuable genetic resource. However, a single reference genome often fails to capture the full extent of their genetic variation. To address this, we construct a pangenome for desi cattle by identifying and characterizing non-reference novel sequences (NRNS).

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Genetic mutation and drift, coupled with natural and human-mediated selection and migration, have produced a wide variety of genotypes and phenotypes in farmed animals. We here introduce the Farm Animal Genotype-Tissue Expression (FarmGTEx) Project, which aims to elucidate the genetic determinants of gene expression across 16 terrestrial and aquatic domestic species under diverse biological and environmental contexts. For each species, we aim to collect multiomics data, particularly genomics and transcriptomics, from 50 tissues of 1,000 healthy adults and 200 additional animals representing a specific context.

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Background: India harbors the world's largest cattle population, encompassing over 50 distinct Bos indicus breeds. This rich genetic diversity underscores the inadequacy of a single reference genome to fully capture the genomic landscape of Indian cattle. To comprehensively characterize the genomic variation within Bos indicus and, specifically, dairy breeds, we aim to identify non-reference sequences and construct a comprehensive pangenome.

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Over the past decades, various methods have been proposed to estimate daily milk yields from partial yields. Many of these methods divide milking interval time into varied classes, assuming that the yield correction factors are constant within classes but vary between classes. The DeLorenzo and Wiggans (D-W) method has been widely used in the United States, typically following a 2-step process.

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Most genotypes in the National Cooperator Database now originate from cows, but most previous studies validating genomic predictions have primarily focused on bulls. This study paired official within-breed genomic PTA (GPTA) and parent average (PA) for genotyped heifer calves born between 2019 and 2021 using the August 2021 database with their corresponding performance deviations (PDEV) for 17 different traits. The PDEV data became available when the heifers completed their first lactation and were extracted from the August 2023 database in which at least one PDEV value for those 17 traits existed for each genotyped heifer record.

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Article Synopsis
  • The productive life of a cow is the time it spends in the milking herd, and researchers studied how genetics affects it using data from a lot of cows.
  • They analyzed over a million Holstein cows with genetic information to find out what genes are linked to how long they can produce milk.
  • The study found many important gene areas that influence not only milk production but also fertility and health, helping to identify which cows should be kept or removed from the herd.
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Telomere-to-telomere (T2T) assemblies reveal new insights into the structure and function of the previously 'invisible' parts of the genome and allow comparative analyses of complete genomes across entire clades. We present here an open collaborative effort, termed the 'Ruminant T2T Consortium' (RT2T), that aims to generate complete diploid assemblies for numerous species of the Artiodactyla suborder Ruminantia to examine chromosomal evolution in the context of natural selection and domestication of species used as livestock.

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Background: We recently identified ~ 10,000 correlated regions of systemic interindividual epigenetic variation (CoRSIVs) in the human genome. These methylation variants are amenable to population studies, as DNA methylation measurements in blood provide information on epigenetic regulation throughout the body. Moreover, establishment of DNA methylation at human CoRSIVs is labile to periconceptional influences such as nutrition.

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Presence-absence variations (PAVs) are important structural variations, wherein a genomic segment containing one or more genes is present in some individuals but absent in others. While PAVs have been extensively studied in plants, research in cattle remains limited. This study identified PAVs in 173 Holstein bulls using whole-genome sequencing data and assessed their associations with 46 economically important traits.

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A genome-wide association study of resistance to retained placenta (RETP) using 632,212 Holstein cows and 74,747 SNPs identified 200 additive effects with -values < 10 on thirteen chromosomes but no dominance effect was statistically significant. The regions of 87.61-88.

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Article Synopsis
  • A genome-wide association study (GWAS) analyzed fat percentage in over 1.2 million first lactation cows and confirmed significant inter-chromosome effects in a specific region on Chromosome 14.
  • The study identified two sub-regions within this area, Chr14a and Chr14b, with Chr14a showing the majority of additive × additive interactions.
  • Notably, the research highlights interactions between specific SNPs (genetic markers) linked to traits like milk production and fertility, enhancing the understanding of genetic influences on fat percentage in Holstein cows.
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The community-based breeding program (CBBP) is an innovative approach recommended for genetic improvement and sustainable use of animal genetic resources in extensive farming systems. Successful implementation of this approach requires an understanding of the characteristics of production systems, breeding objectives, and farmers' trait preference. This study aimed to identify the selection criteria of goat farmers in rural areas of Burkina Faso and their potential implications in establishing CBBP.

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Article Synopsis
  • The paper emphasizes the need for simultaneous advancements in genomics (measuring genetic variation) and phenomics (measuring trait variation) for agricultural populations to improve agricultural productivity.
  • It discusses the Agricultural Genome to Phenome Initiative (AG2PI) and its efforts to coordinate with government agencies and stakeholders to improve agricultural outcomes through research collaboration.
  • A workshop was held to identify challenges and innovation opportunities in AG2P research, resulting in a vision for future advancements and six specific goals for immediate implementation.
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Various methods have been proposed to estimate daily yield from partial yields, primarily to deal with unequal milking intervals. This paper offers an exhaustive review of daily milk yields, the foundation of lactation records. Seminal advancements in the late 20th century concentrated on two main adjustment metrics: additive additive correction factors (ACF) and multiplicative correction factors (MCF).

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The African Goat Improvement Network Image Collection Protocol (AGIN-ICP) is an accessible, easy to use, low-cost procedure to collect phenotypic data via digital images. The AGIN-ICP collects images to extract several phenotype measures including health status indicators (anemia status, age, and weight), body measurements, shapes, and coat color and pattern, from digital images taken with standard digital cameras or mobile devices. This strategy is to quickly survey, record, assess, analyze, and store these data for use in a wide variety of production and sampling conditions.

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This study compared 3 correlational (best prediction, linear regression, and feed-forward neural networks) and 2 causal models (recursive structural equation model and recurrent neural networks) for estimating lactation milk yields. The correlational models assumed associations between test-day milk yields (health conditions), while the casual models postulated unidirectional recursive effects between these test-day variables. Wood lactation curves were used to simulate the data and served as a benchmark model.

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The African Goat Improvement Network (AGIN) is a collaborative group of scientists focused on genetic improvement of goats in small holder communities across the African continent. The group emerged from a series of workshops focused on enhancing goat productivity and sustainability. Discussions began in 2011 at the inaugural workshop held in Nairobi, Kenya.

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Article Synopsis
  • In the U.S., milk yields are calculated from test-day yields, which are derived from partial yields from single milkings, with various methods developed to address issues from uneven milking intervals since the 70s and 80s.
  • The Wiggans model is a widely used method for estimating test-day yields, but it assumes a linear relationship that doesn't fit well with Holstein cows milked twice a day due to inconsistent milking intervals.
  • Recent studies highlight nonlinear models as more accurate alternatives to conventional methods, offering improved estimation of test-day milk yields by avoiding inaccuracies from simplified interval corrections and utilizing flexible modeling approaches.
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In Burkina Faso, goats are the second most numerous ruminant livestock population, with almost exclusively indigenous breeds being reared in extensive production systems in various agroecological zones. This study was carried out to understand the morphological variation of local goat breeds in the Sudano-Sahelian and Sudanian agroecological zones. A total of 511 adult female animals belonging to two presumed populations (Mossi breed in Sudano-Sahelian zone and Djallonké breed in Sudanian zone) were sampled and body weight as well as a range of linear body measurements, following FAO guidelines, were recorded.

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Cows are typically milked 2 or more times on a test-day, but not all these milkings are sampled and weighed. The initial approach estimated a test-day yield with doubled morning (AM) or evening (PM) yield in the AM-PM milking plans, assuming equal AM and PM milking intervals. However, AM and PM milking intervals can vary, and milk secretion rates may be different between day and night.

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The calculation of exact reliabilities involving the inversion of mixed model equations poses a heavy computational challenge when the system of equations is large. This has prompted the development of different approximation methods. We give an overview of the various methods and computational approaches in calculating reliability from the era before the animal model to the era of single-step genomic models.

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