Jul 2026· Schweizer Archiv für Tierheilkunde· Vol 168 7, pp.
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· 0 citations
Medicine
Abstract
INTRODUCTION
Suckler cow farming is a key part of Swiss beef production, representing extensive farming practices and high standards of animal welfare. Around 7 % of the country's cattle are registered with the relevant breeding association. Switzerland boasts a high degree of genetic diversity, with 38 beef and dual-purpose breeds. This study aimed to systematically catalogue known recessive genetic defects and selected inherited traits of the most common Swiss suckler cow breeds and determine their prevalence. Worldwide, 67 monogenic recessive genetic defects have been identified in beef cattle. Of these, 42 - caused by 45 known gene variants - affect the ten most commonly kept suckler cow breeds in Switzerland. Currently, 40 causative gene variants for 37 genetic defects are routinely tested in Switzerland. No carrier animals have yet been identified for 13 of these variants. In contrast, heterozygous carriers were rarely identified for a total of 27 variants. The breed-specific allele frequencies exceeded 1 % for 14 harmful alleles. The causal variant for retinitis pigmentosa 1 was particularly widespread in Charolais and Angus cattle, as was the causal variant for developmental duplication in Angus cattle. Additionally, single homozygous affected animals were confirmed for the first time in Switzerland: tibial hemimelia in Galloway cattle and progressive ataxia in Charolais cattle. In addition to genetic defects, breeding-relevant monogenic traits such as muscle hypertrophy and hornlessness are also examined. These traits sometimes occur with high allele frequencies in several breeds and can therefore be targeted specifically in breeding programs. SWISScow SNP array genotyping enables harmful recessive alleles to be monitored. Suspected cases should be reported and investigated. Digital breeding planning tools help to avoid risk matings of heterozygous carriers, thereby reducing reproductive losses and improving animal health and welfare in the long term.
Simple Summary Sheep play an important role in food production and rural livelihoods, especially in regions where locally adapted breeds have developed unique traits. Two key characteristics that influence sheep productivity are the number of lambs born per ewe (prolificacy) and coat color, which can affect adaptation and market value. This study evaluated genetic variations in 15 Brazilian sheep breeds using a set of 48 genetic markers related to these traits. Our findings suggest that a specific mutation in the GDF9 gene may be associated with increased lamb production in the Brazilian Blackbelly, in addition to Santa Inês and Morada Nova breeds where it has previously been associated with prolificacy. Other genes formerly linked with enhanced reproductive performance did not show relevant effects in these locally adapted breeds. Genetic differences were also identified in genes influencing coat color, helping to explain the diversity observed between hair and wool sheep. Importantly, the genetic material stored in the Brazilian Animal Germplasm Bank (BBGA) preserves much of the diversity found in populations conserved in situ. These findings contribute to the conservation and sustainable use of local sheep breeds, supporting genetic improvement programs and helping ensure food security and biodiversity for future generations.
Camila Souza Rodrigues, D. A. Faria, H. C. Azevedo et al.· Animals· 0 citations
This paper investigates different selection scenarios to reduce the prevalence of a genetic defect in a vulnerable breed, using simulations of selection against gonadal hypoplasia in Swedish Mountain Cattle as a case study. Gonadal hypoplasia (reduced size of ovaries/testes) that leads to reduced fertility has long been a problem in Swedish Mountain cattle (Fjällko). Despite breeding efforts that have reduced the frequency of the defect, it is still present in the breed. There are two translocations involving chromosomes 6 and 29 associated with desired colour phenotypes that segregates in several Swedish local cattle breeds. One of these is associated with gonadal hypoplasia although there is incomplete penetrance. With modern DNA methods it is possible to detect the carriers of this defect and tackle this old problem, but the key issue is to do this without harming genetic diversity. We performed simulations with allele frequencies and penetrance that have been estimated previously in the breed and different scenarios of marker-assisted selection. The simulated scenarios were: genetic testing of potential bulls prior to selection to exclude carriers or homozygotes for the deleterious allele; genetic testing of bulls used for artificial insemination to exclude carriers or homozygotes for the deleterious allele; and genetic testing of bulls used for artificial insemination but where 1 or 5 carrier sires were allowed to be used. Simulations showed that it is possible to reduce the frequency of the allele causing the genetic defect while maintaining the effective population size. This however comes with a cost of requiring many genetic tests. Based on these results, the most promising approach would be to pre-screen bull calves before selection of sires, maintaining the number of bulls that are used. These results suggest that efforts to genotype and phenotype cattle for validation and testing of the marker in Swedish Mountain cattle is warranted.
Ebba Gustafsson, Anna M. Johansson, M. Johnsson· PLoS ONE· 0 citations
Recommendations are formulated for building a genetic health management system in beef cattle breeding, based on mandatory DNA testing, inbreeding control, accounting for pleiotropic effects in selection, and the integration of advanced biotechnologies.
N. Bezborodova, O. Sokolova, O. S. Zaitseva et al.· International Journal of Vet...· 0 citations
The Brown Swiss (BS) cattle breed is one of the major Swiss dairy breeds. Intensive selection and the widespread use of few elite sires in artificial insemination have increased inbreeding and the occurrence of deleterious recessive alleles in the homozygous state. Analyzing life trajectories in large, genotyped cohorts can identify hidden recessive disorders that are difficult to detect using traditional case-control association testing. Long-read DNA sequencing enables precise detection of causal alleles, including structural variants. This study aimed to (1) identify cryptic recessive loci affecting rearing performance in Swiss BS cattle, (2) evaluate their impact on survival, (3) characterize the associated phenotype, (4) identify the causal variant using long-read whole-genome sequencing, and (5) assess its functional impact. Using Homozygous Haplotype Enrichment/Depletion (HHED) mapping, we identified a risk haplotype (BH39) on chromosome 15 spanning from 16,276,819 bp to 16,446,984 bp that was associated with increased juvenile mortality within the first 180 days of life when present in the homozygous state. The BH39 occurred at a frequency of approximately 4.5% in Swiss BS cattle and 5.3% in German and Austrian BS cattle, and homozygous carriers exhibited a significantly reduced first-year survival rate. Five females homozygous for BH39 underwent clinical examination. They all showed recurrent respiratory disease, impaired growth, poor body condition, rough hair coat, and brown-discolored teeth. Pathological examination revealed bronchopneumonia and eosinophilic enteritis. Clinicopathological findings indicated failure to thrive and immunodeficiency. Long-read WGS of two BH39 homozygous calves revealed a private homozygous coding variant that was in high linkage disequilibrium with BH39. The identified structural variant was an insertion of a large transposable element (10.4 kb ERVK[2-1-LTR]) into the third exon of ALKBH8 (NM_001080341.2 c.267_268indel). Full-length RNA sequencing of cerebellum and liver from a homozygous calf revealed that the endogenous retrovirus (ERV) insertion introduces a cryptic transcription termination signal, truncating ALKBH8 mRNA. This study demonstrates that exploring population-scale genomic data and mining thousands of life-history records, followed by veterinary follow-up evaluations and molecular genetic analyses, provides an effective strategy for identifying cryptic recessive disorders that shorten the lifespan of cattle. The findings provide strong evidence that the ERV insertion into the coding sequence of ALKBH8 represents a loss-of-function variant that causes a previously undescribed recessive disorder that results in increased rearing loss. Interpretive summary We identified a recessive disorder in Brown Swiss cattle that causes retarded growth, recurrent infections, immunodeficiency, and increased mortality during the first year of life. Using population-scale genomic data, clinical investigations, and long-read sequencing, we linked the disorder to an exonic transposable element insertion disrupting ALKBH8. The identification of the causal variant now enables direct genetic testing and the implementation of genome-based mating strategies to avoid carrier-by-carrier matings and, consequently, prevent the birth of affected homozygous offspring. We demonstrate the utility of integrating large-scale breeding records, veterinary phenotyping, and advanced genomics to identify hidden defects affecting livestock health and productivity.
S. Glatthard, N. Kadri, F. Seefried et al.· bioRxiv· 0 citations
Kazakhstan ruminant genomics is expanding through targeted diagnostic testing, SNP-array studies, whole-genome sequencing, runs of homozygosity, candidate-gene analyses, transcriptomic studies and pathogen molecular diagnostics. However, these evidence types differ substantially in their relevance for breeding decisions. This structured narrative review evaluates molecular evidence for inherited disorders, deleterious alleles, disease-resistance loci, reproductive genes and genomic-health indicators in Kazakhstan cattle, sheep and goats. We define actionable evidence as evidence that can directly inform breeding management because it involves a validated pathogenic variant, risk variant or fertility haplotype detected or excluded in breeding-relevant animals or germplasm. Under this definition, cattle currently provide the strongest immediately actionable evidence, mainly because targeted studies have screened validated defects and fertility-related loci in artificial-insemination bulls, imported germplasm or breed-relevant populations. Evidence includes Kazakhstan-associated screening for BLAD (Bovine leukocyte adhesion deficiency), DUMPS (Deficiency of uridine monophosphate synthase), hypotrichosis, OH1-associated achromatopsia, fertility haplotypes and several beef- or dairy-breed recessive defects. In sheep, evidence is broader but less directly actionable, consisting mainly of prion protein gene preparedness, MHC (Major histocompatibility complex)-related immune hypotheses, reproductive candidate loci, runs of homozygosity, genome wide associated data and pathogen-exposure context. In goats, current evidence is mostly population-genomic and adaptation-oriented, while hereditary-disease surveillance and phenotype-linked resistance studies remain sparse. We propose an author-defined staged genomic-health framework that separates validated carrier-screening evidence from candidate genomic signals and international evidence requiring local validation. Priority actions include carrier-aware management of high-impact cattle germplasm, representative prion protein gene and runs of homozygosity baselines in small ruminants, phenotype-first surveillance, biobanking and national genotype–phenotype databases.
A. Mussayeva, N. Malmakov, Berik Aringaziev et al.· International Journal of Mol...· 0 citations
The article presents the results of studies aimed at determining the effect of the main genetic and paratypic factors on the quality indicators of milk in order to develop scientifically grounded proposals for improving the quality of produced products. Among the studied livestock, 41.7-65.5% of animals have the desired genotype, heterozygous animals with one desired A2 allele – 30.0-45.8% and homozygous and heterozygous animals with two undesirable A1, B alleles from 4.4 to 15.0%, which is of practical importance for targeted breeding work in terms of the production of raw milk with specified technological properties for cheese making and other processing areas, which will increase the competitiveness of the products and their safety.
V. Timoshenko, N. I. Pyasotski, A. Muzyka et al.· Transactions of the educatio...· 0 citations