Identification of genomic regions associated with differences in fleece type in Huacaya and Suri alpacas (Vicugna pacos).

The difference in fleece type is the distinguishing trait between the two types of alpacas (Vicugna pacos), Huacaya and Suri. The Suri fleece type has been found to be inherited dominantly over the Huacaya type, resulting in offspring with the Suri phenotype. The aim of our study was to map genomic regions associated with the two different fleece types. In this study, 91 alpacas (54 Huacayas and 37 Suris) from Germany and Switzerland were genotyped using the 76k alpaca SNP array. Only 59k chromosome-localised markers map to the alpaca reference assembly VicPac3.1, and after quality control 49 866 SNPs, were retained for population structure assessment and to conduct a genome-wide association study. Both principal component and neighbour-joining tree analysis showed that the two fleece-type cohorts overlapped rather than forming two distinct clusters. Genome-wide significantly associated markers were observed in the scaffold region of chromosome 16 (NW_021964192.1), which contains a cluster of keratin genes. A haplotype predominantly found in Suri alpacas has been identified which supports dominant inheritance. Variant filtering of nine whole-genome sequenced alpacas from both fleece types in the critical interval of 0.4 Mb did not reveal perfect segregation of either fleece type for specific variants. To our knowledge, this is the first study to use the recently developed species-specific SNP array to identify genomic regions associated with differences in fleece type in alpacas. There are still some limitations, such as the preliminary status of the reference assembly and the incomplete annotation of the alpaca genome.

Ear type in sheep is associated with the MSRB3 locus.

Ear morphology is an important determinant of sheep breeds. It includes different variable traits such as ear size and erectness, suggesting a polygenic architecture. Here, we performed a comprehensive genome-wide analysis to identify regions under selection for ear morphology in 515 sheep from 17 breeds fixed for diverse ear phenotypes using 34k SNP genotyping data. GWASs for two ear type traits, size and erectness, revealed a single genome-wide significant association on ovine chromosome 3. The derived marker alleles were enriched in sheep with large and/or floppy ears. The GWAS signal harboured the MSRB3 gene encoding methionine sulphoxide reductase B3, which has already been found to be associated with different ear types in other species. We attempted whole-genome resequencing to identify causal variant(s) within a 1 Mb interval around MSRB3. This experiment excluded major copy number variants in the interval, but failed to identify a compelling candidate causal variant. Fine-mapping suggested that the causal variant for large floppy ears most likely resides in a 175 kb interval downstream of the MSRB3 coding region.

De novo stop-lost germline mutation in FGFR3 causes severe chondrodysplasia in the progeny of a Holstein bull.

Fifteen cases of chondrodysplasia characterized by disproportionate dwarfism occurred in the progeny of a single Holstein bull. A de novo mutation event in the germline of the sire was suspected as cause. Whole-genome sequencing revealed a single protein-changing variant in the stop codon of FGFR3 gene on chromosome 6. Sanger sequencing of EDTA blood proved that this variant occurred de novo and segregates perfectly with the observed phenotype in the affected cattle family. FGFR3 is an important regulator gene in bone formation owing to its key role in the bone elongation induced by FGFR3-dimers. The detected paternally inherited stop-lost variant in FGFR3 is predicted to add 93 additional amino acids to the protein's C-terminus. This study provides a second example of a dominant FGFR3 stop-lost variant as a pathogenic mutation of a severe form of chondrodysplasia. Even though FGFR3 is known to be associated with dwarfism and growth disorders in human and sheep, this study is the first to describe FGFR3-associated chondrodysplasia in cattle.

A de novo germline mutation of KIT in a white-spotted Brown Swiss cow.

White-spotting coat colour phenotypes in cattle are either fixed characteristics of specific cattle breeds or occur sporadically owing to germline genetic variation of solid-coloured parents. A Brown Swiss cow showing a piebald pattern resembling colour-sidedness was referred for genetic evaluation. Both parents were normal solid-brown-coloured cattle. The cow was tested negative for the three known DNA variants in KIT, MITF and TWIST2 associated with different depigmentation phenotypes in Brown Swiss cattle. Whole-genome sequencing of the cow was performed and a heterozygous variant affecting the coding sequence of the bovine KIT gene was identified on chromosome 6. The variant is a 40 bp deletion in exon 9, NM_001166484.1:c.1390_1429del, and leads to a frameshift that is predicted to produce a novel 50 amino acid-long C-terminus replacing almost 50% of the wt KIT protein, including the functionally important intracellular tyrosine kinase domain (NP_001159956.1:p.(Asn464AlafsTer50)). Interestingly, among three available offspring, two solid-coloured daughters were genotyped as homozygous wt whereas a single son showing a slightly milder but still obvious depigmentation phenotype inherited a copy of the novel variant allele. The genetic findings provide strong evidence that the identified loss-of-function KIT variant most likely represents a de novo germline mutation that is causative owing to haploinsufficiency.

A genome-wide significant association on chromosome 15 for congenital entropion in Swiss White Alpine sheep.

Entropion is a known congenital disorder in sheep presumed to be heritable but no causative genetic variant has been reported. Affected lambs show a variable inward rolling of the lower eyelids leading to blindness in severe cases. In Switzerland, the Swiss White Alpine (SWA) breed showed a significantly higher prevalence for entropion than other breeds. A GWAS using 150 SWA sheep (90 affected lambs and 60 controls), based on 600k SNP data, revealed a genome-wide significant signal on chromosome 15. The 0.2 Mb associated region contains functional candidate genes, SMTNL1 and CTNND1. Pathogenic variants in human CTNND1 cause blepharocheilodontic syndrome 2, a rare disorder including eyelid anomalies, and SMTNL1 regulates contraction and relaxation of skeletal and smooth muscle. WGS of a single entropion-affected lamb revealed two private missense variants in SMTNL1 and CTNND1. Subsequent genotyping of both variants in 231 phenotyped SWA sheep was performed. The SMTNL1 variant p.(Asp452Asn) affects an evolutionary conserved residue within an important domain and represents a rare allele, which occurred also in controls. The p.(Glu943Lys) variant in CTNND1 represents a common variant unlikely to cause entropion as the mutant allele occurred more frequently in non-affected sheep. Therefore, we propose that these protein-changing variants are unlikely to explain the phenotype. Additionally, WGS of three further disconcordant pairs of full siblings was carried out but revealed no obvious causative variant. Finally, we conclude that entropion represents a more complex disease caused by different non-coding regulatory variants.

A deletion spanning the promoter and first exon of the hair cycle-specific ASIP transcript isoform in black and tan rabbits.

Black and tan animals have tan-coloured ventral body surfaces separated by sharp boundaries from black-coloured dorsal body surfaces. In the at mouse mutant, a retroviral 6 kb insertion located in the hair cycle-specific promoter of the murine Asip gene encoding agouti signalling protein causes the black and tan phenotype. In rabbits, three ASIP alleles are thought to exist, including an at allele causing a black and tan coat colour that closely resembles the mouse black and tan phenotype. The goal of our study was to identify the functional genetic variant causing the rabbit at allele. We performed a WGS-based comparative analysis of the ASIP gene in one black and tan and three wt agouti-coloured rabbits. The analysis identified 75 at -associated variants including an 11 kb deletion. The deletion is located in the region of the hair cycle-specific ASIP promoter and thus in a region homologous to the site of the retroviral insertion causing the at allele in mice. We observed perfect association of the genotypes at this deletion with the coat colour phenotype in 49 rabbits. The comparative analysis and the previous knowledge about the regulation of ASIP expression suggest that the 11 kb deletion is the most likely causative variant for the black and tan phenotype in rabbits.

New genomic features of the polled intersex syndrome variant in goats unraveled by long-read whole-genome sequencing.

In domestic goats, the polled intersex syndrome (PIS) refers to XX female-to-male sex reversal associated with the absence of horn growth (polled). The causal variant was previously reported as a 11.7 kb deletion at approximately 129 Mb on chromosome 1 that affects the transcription of both FOXL2 and several long non-coding RNAs. In the meantime the presence of different versions of the PIS deletion was postulated and trials to establish genetic testing with the existing molecular genetic information failed. Therefore, we revisited this variant by long-read whole-genome sequencing of two genetically female (XX) goats, a PIS-affected and a horned control. This revealed the presence of a more complex structural variant consisting of a deletion with a total length of 10 159 bp and an inversely inserted approximately 480 kb-sized duplicated segment of a region located approximately 21 Mb further downstream on chromosome 1 containing two genes, KCNJ15 and ERG. Publicly available short-read whole-genome sequencing data, Sanger sequencing of the breakpoints and FISH using BAC clones corresponding to both involved genome regions confirmed this structural variant. A diagnostic PCR was developed for simultaneous genotyping of carriers for this variant and determination of their genetic sex. We showed that the variant allele was present in all 334 genotyped polled goats of diverse breeds and that all analyzed 15 PIS-affected XX goats were homozygous. Our findings enable for the first time a precise genetic diagnosis for polledness and PIS in goats and add a further genomic feature to the complexity of the PIS phenomenon.

Identification of small and large genomic candidate variants in bovine pulmonary hypoplasia and anasarca syndrome.

The pulmonary hypoplasia and anasarca syndrome (PHA) is a congenital lethal disorder, which until now has been reported in cattle and sheep. PHA is characterized by extensive subcutaneous fetal edema combined with hypoplasia or aplasia of the lungs and dysplasia of the lymphatic system. PHA is assumed to be of genetic etiology. This study presents the occurrence of PHA in two different cattle breeds and their genetic causation. Two PHA cases from one sire were observed in Slovenian Cika cattle. Under the assumption of monogenic inheritance, genome-wide homozygosity mapping scaled down the critical regions to 3% of the bovine genome including a 43.6 Mb-sized segment on chromosome 6. Whole-genome sequencing of one case, variant filtering against controls and genotyping of a larger cohort of Cika cattle led to the detection of a likely pathogenic protein-changing variant perfectly associated with the disease: a missense variant on chromosome 6 in ADAMTS3 (NM_001192797.1: c.1222C>T), which affects an evolutionary conserved residue (NP_001179726.1: p.(His408Tyr)). A single PHA case was found in Danish Holstein cattle and was whole-genome sequenced along with its parents. However, as there was no plausible private protein-changing variant, mining for structural variation revealed a likely pathogenic trisomy of the entire chromosome 20. The identified ADAMTS3 associated missense variant and the trisomy 20 are two different genetic causes, which shows a compelling genetic heterogeneity for bovine PHA.

A comprehensive biomedical variant catalogue based on whole genome sequences of 582 dogs and eight wolves.

The domestic dog serves as an excellent model to investigate the genetic basis of disease. More than 400 heritable traits analogous to human diseases have been described in dogs. To further canine medical genetics research, we established the Dog Biomedical Variant Database Consortium (DBVDC) and present a comprehensive list of functionally annotated genome variants that were identified with whole genome sequencing of 582 dogs from 126 breeds and eight wolves. The genomes used in the study have a minimum coverage of 10× and an average coverage of ~24×. In total, we identified 23 133 692 single-nucleotide variants (SNVs) and 10 048 038 short indels, including 93% undescribed variants. On average, each individual dog genome carried ∼4.1 million single-nucleotide and ~1.4 million short-indel variants with respect to the reference genome assembly. About 2% of the variants were located in coding regions of annotated genes and loci. Variant effect classification showed 247 141 SNVs and 99 562 short indels having moderate or high impact on 11 267 protein-coding genes. On average, each genome contained heterozygous loss-of-function variants in 30 potentially embryonic lethal genes and 97 genes associated with developmental disorders. More than 50 inherited disorders and traits have been unravelled using the DBVDC variant catalogue, enabling genetic testing for breeding and diagnostics. This resource of annotated variants and their corresponding genotype frequencies constitutes a highly useful tool for the identification of potential variants causative for rare inherited disorders in dogs.

Runs of homozygosity and signatures of selection: a comparison among eight local Swiss sheep breeds.

A dataset consisting of 787 animals with high-density SNP chip genotypes (346 774 SNPs) and 939 animals with medium-density SNP chip genotypes (33 828 SNPs) from eight indigenous Swiss sheep breeds was analyzed to characterize population structure, quantify genomic inbreeding based on runs of homozygosity and identify selection signatures. In concordance with the recent known history of these breeds, the highest genetic diversity was observed in Engadine Red sheep and the lowest in Valais Blacknose sheep. Correlation between FPED and FROH was around 0.50 and thereby lower than that found in similar studies in cattle. Mean FROH estimates from medium-density data and HD data were highly correlated (0.95). Signatures of selection and candidate gene analysis revealed that the most prominent signatures of selection were found in the proximity of genes associated with body size (NCAPG, LCORL, LAP3, SPP1, PLAG1, ALOX12, TP53), litter size (SPP1), milk production (ABCG2, SPP1), coat color (KIT, ASIP, TBX3) and horn status (RXFP2). For the Valais Blacknose sheep, the private signatures in proximity of genes/QTL influencing body size, coat color and fatty acid composition were confirmed based on runs of homozygosity analysis. These private signatures underline the genetic uniqueness of the Valais Blacknose sheep breed. In conclusion, we identified differences in the genetic make-up of Swiss sheep breeds, and we present relevant candidate genes responsible for breed differentiation in locally adapted breeds.

Identification of two TYRP1 loss-of-function alleles in Valais Red sheep.

The Valais Red sheep breed is a local breed of the Swiss canton Valais. Although the breed is characterised by its brown colour, black animals occasionally occur and the objective of this study was to identify the causative genetic variants responsible for the obvious difference. A GWAS using high-density SNP data to compare 51 brown and 38 black sheep showed a strong signal on chromosome 2 at the TYRP1 locus. Haplotype analyses revealed three different brown-associated alleles. The WGS of three sheep revealed four protein-changing variants within the TYRP1 gene. Three of these variants were associated with the recessively inherited brown coat colour. This includes the known missense variant TYRP1:c.869G>T designated as bS oay and two novel loss-of-function variants. We propose to designate the frame-shift variant TYRP1:c.86_87delGA as bVS 1 and the nonsense variant TYRP1:c.1066C>T as bVS 2 . Interestingly, the bVS 1 allele occurs only in local breeds of Switzerland whereas the bVS 2 allele seems to be more widespread across Europe.

Comprehensive characterization of horse genome variation by whole-genome sequencing of 88 horses.

Whole-genome sequencing studies are vital to gain a thorough understanding of genomic variation. Here, we summarize the results of a whole-genome sequencing study comprising 88 horses and ponies from diverse breeds at 19.1× average coverage. The paired-end reads were mapped to the current EquCab3.0 horse reference genome assembly, and we identified approximately 23.5 million single nucleotide variants and 2.3 million short indel variants. Our dataset included at least 7 million variants that were not previously reported. On average, each individual horse genome carried ∼5.7 million single nucleotides and 0.8 million small indel variants with respect to the reference genome assembly. The variants were functionally annotated. We provide two examples for potentially deleterious recessive alleles that were identified in a heterozygous state in individual genome sequences. Appropriate management of such deleterious recessive alleles in horse breeding programs should help to improve fertility and reduce the prevalence of heritable diseases. This comprehensive dataset has been made publicly available, will represent a valuable resource for future horse genetic studies and supports the goal of accelerating the rates of genetic gain in domestic horse.

A non-coding regulatory variant in the 5'-region of the MITF gene is associated with white-spotted coat in Brown Swiss cattle.

Recently, the Swiss breeding association reported an increasing number of white-spotted cattle in the Brown Swiss breed, which is normally solid brown coloured. A total of 60 Brown Swiss cattle with variably sized white abdominal spots, facial markings and depigmented claws were collected for this study. A genome-wide association study using 40k SNP genotypes of 20 cases and 1619 controls enabled us to identify an associated genome region on chromosome 22 containing the MITF gene, encoding the melanogenesis associated transcription factor. Variants at the MITF locus have been reported before to be associated with white or white-spotted phenotypes in other species such as horses, dogs and mice. Whole-genome sequencing of a single white-spotted cow and subsequent genotyping of 172 Brown Swiss cattle revealed two significantly associated completely linked single nucleotide variants (rs722765315 and rs719139527). Both variants are located in the 5'-regulatory region of the bovine MITF gene, and comparative sequence analysis showed that the variant rs722765315, located 139 kb upstream of the transcription start site of the bovine melanocyte-specific MITF transcript, is situated in a multi-species conserved sequence element which is supposed to be regulatory important. Therefore, we hypothesize that rs722765315 represents the most likely causative variant for the white-spotting phenotype observed in Brown Swiss cattle. Presence of the mutant allele in a heterozygous or homozygous state supports a dominant mode of inheritance with incomplete penetrance and results in a variable extent of coat colour depigmentation.

An ABCA12 missense variant in a Shorthorn calf with ichthyosis fetalis.

Two clinical forms of ichthyosis in cattle have been reported, ichthyosis fetalis and congenital ichthyosis. Ichthyosis poses animal welfare and economic issues and the more severe form, ichthyosis fetalis, is lethal. A Shorthorn calf with ichthyosis fetalis was investigated and a likely causal missense variant on chromosome 2 in the ABCA12 gene (NM_001191294.2:c.6776T>C) was identified by whole genome sequencing. Mutations in the ABCA12 gene are known to cause ichthyosis fetalis in cattle and Harlequin ichthyosis in humans. Sanger sequencing of the affected calf and the dam confirmed the variant was homozygous in the affected calf and heterozygous in the dam. Further genotyping of 130 Shorthorn animals from the same property revealed an estimated allele frequency of 3.8%. The presented findings enable genetic testing for breeding and diagnostics.

A complex structural variant at the KIT locus in cattle with the Pinzgauer spotting pattern.

A specific white spotting phenotype, termed finching or line-backed spotting, is known for all Pinzgauer cattle and occurs occasionally in Tux-Zillertaler cattle, two Austrian breeds. The so-called Pinzgauer spotting is inherited as an autosomal incompletely dominant trait. A genome-wide association study using 27 white spotted and 16 solid-coloured Tux-Zillertaler cattle, based on 777k SNP data, revealed a strong signal on chromosome 6 at the KIT locus. Haplotype analyses defined a critical interval of 122 kb downstream of the KIT coding region. Whole-genome sequencing of a Pinzgauer cattle and comparison to 338 control genomes revealed a complex structural variant consisting of a 9.4-kb deletion and an inversely inserted duplication of 1.5 kb fused to a 310-kb duplicated segment from chromosome 4. A diagnostic PCR was developed for straightforward genotyping of carriers for this structural variant (KITPINZ ) and confirmed that the variant allele was present in all Pinzgauer and most of the white spotted Tux-Zillertaler cattle. In addition, we detected the variant in all Slovenian Cika, British Gloucester and Spanish Berrenda en negro cattle with similar spotting patterns. Interestingly, the KITPINZ variant occurs in some white spotted animals of the Swiss breeds Evolèner and Eringer. The introgression of the KITPINZ variant confirms admixture and the reported historical relationship of these short-headed breeds with Austrian Tux-Zillertaler and suggests a mutation event, occurring before breed formation.

The APOB loss-of-function mutation of Holstein dairy cattle does not cause a deficiency of cholesterol but decreases the capacity for cholesterol transport in circulation.

The loss-of-function mutation of the apolipoprotein (APO) B gene (APOB) in Holstein cattle accounts for increased losses in calves that are homozygous for this mutation. Heterozygous carriers of the APOB mutation are clinically healthy but show decreased concentrations of plasma cholesterol and lipoproteins. So far, the metabolic effects of the mutation have only been investigated in heterozygous calves, bulls, and nonlactating females. In high-yielding dairy cows, a marked decrease in cholesterol concentration in plasma during early lactation is part of the usual metabolic changes. Given the essential role of cholesterol in fatty acid and lipid metabolism, a specific effect of the APOB mutation on metabolism and performance in dairy cows is expected. Therefore, the aim of the present study was to investigate the effects of different APOB genotypes on metabolic parameters, hepatic metabolism, and lactation and reproductive performance. Twenty pairs of full siblings with similar age, performance, and calving were investigated. Both animals of each pair were kept on the same farm and consisted of a heterozygous carrier (CDC) and a noncarrier (CDF) of the APOB mutation associated with cholesterol deficiency. Blood samples were taken in early (25.5 ± 4.7 d in milk) and mid lactation (158.2 ± 11.1 d in milk; mean ± SD), and analyzed for nonesterified fatty acids, ß-hydroxybutyrate, glucose, insulin-like growth factor-1, aspartate aminotransferase and gamma-glutamyltransferase activity, total cholesterol, free cholesterol, triacylglycerols, high density lipoprotein-cholesterol, and phospholipids. The evaluation of milk production, milk gross composition, and lactation persistency was based on official Dairy Herd Improvement Association recordings. Cholesterol and lipoprotein concentrations were lower in CDC cows than in CDF cows in early and mid lactation. Metabolic parameters, triacylglycerol concentration in plasma, and lactation and reproductive performance did not differ between CDC cows and CDF cows. The low cholesterol concentrations associated with the APOB mutation in heterozygous carriers are not because of a primary deficiency of cholesterol at a cellular level, as the term "cholesterol deficiency" suggests, but rather a consequence of reduced capacity for its transport in circulation. Overall, the data of the present study suggest that, despite the presence of the APOB mutation, cholesterol is not limiting for animals' metabolic adaptation and performance in heterozygous Holstein cows.

[Unilateral peromelia of the left pelvic limb in a Brown Swiss calf]. / Unilaterale Peromelie der linken Beckengliedmasse bei einem Brown Swiss Kalb.

INTRODUCTION: Congenital deformities of the limbs occur sporadically in various species, but the cause is often unclear. The clinically healthy female Brown Swiss calf presented here showed a congenital peromelia of the left hind limb. The affected limb is twisted, disproportional and the bones distally of the metatarsus are missing. Karyotyping and genome sequencing did not indicate on a genetic cause of the anomaly. An infection with the Schmallenberg virus could not be ruled out. Furthermore, there was no evidence of further adverse environmental effects during pregnancy.

INTRODUCTION: Des malformations congénitales des membres, dont la cause est souvent peu claire, surviennent sporadiquement chez diverses espèces. Le veau Brown Swiss femelle présenté ici, tout en étant cliniquement sain, présentait une péromélie congénitale du postérieur gauche. Le membre concerné été en rotation interne, disproportionné et les os distalement au métatarse étaient absents. La détermination du caryotype et le séquençage de l'ensemble du génome n'ont apporté aucun élément parlant pour une cause génétique de l'anomalie. Il n'a pas été possible d'exclure une infection par le virus de ­Schmallenberg. D'autre part il n'y avait aucun élément évoquant d'autres influences environnementales néfastes durant la gestation.

Evaluation of HOXC8 in crested Swiss chicken.

The crest in chicken consists of elongated and upraised feathers, as seen in various breeds such as the Silkie chicken. Recently, the still unknown causative mutation for the crest phenotype was assigned to chromosome 33 and an ectopic expression of HOXC8 was shown. The aim this study was to evaluate whether the crest phenotype in a local Swiss chicken breed, the Appenzeller Spitzhaubenhuhn, is associated with HOXC8. Three previously reported crest-associated flanking markers at the HOXC8 locus were genotyped in cohorts of this breed and two other local breeds without the crest phenotype. For the Appenzeller Spitzhaubenhuhn chicken showing the crest phenotype, no clear association of the reported markers could be revealed. Furthermore, the two exons of HOXC8 were sequenced in crested chicken of the Appenzeller Spitzhaubenhuhn and Silkie breeds and revealed no evidence of polymorphisms within the coding region of HOXC8. Therefore, the molecular genetic etiology for the crest phenotype in the investigated breeds remains unclear.

Genetic risk for squamous cell carcinoma of the nictitating membrane parallels that of the limbus in Haflinger horses.

Squamous cell carcinoma (SCC) is the most common cancer affecting the equine eye, with a higher incidence documented in Haflinger horses. Recently, a missense variant in the gene damage specific DNA binding protein 2 (DDB2, p.Thr338Met) on ECA12 was identified as a risk factor for the development of limbal SCC in Haflinger horses. SCC also occurs on the nictitating membrane; therefore, investigating the role of this missense variant in nictitating membrane SCC is warranted. In this study, a common ancestor was identified among Haflinger horses affected with limbal SCC or with nictitating membrane SCC, thus supporting a recessive risk factor for the development of cancer at both ocular locations. Analysis of genotype data from Haflinger horses with and without nictitating membrane SCC revealed that the same region on ECA12 associated with limbal SCC was also associated with nictitating membrane SCC (P < 2.04 × 10-5 ). Fine mapping of this locus using 25 cases and 49 controls supported the hypothesis that DDB2:c.1013C>T, p.Thr338Met, is a risk factor for nictitating membrane SCC, as 88% of our cases were homozygous for this variant and no other polymorphism was more strongly associated (P = 4.13 × 10-14 ). These data indicate that the genetic risk is the same for the development of both limbal and nictitating membrane SCC in Haflinger horses and validates utilization of genetic testing of the DDB2 variant for both clinical management and the guidance of mating decisions.

[Bovine dilated cardiomyopathy: Almost forgotten but still present]. / Bovine dilatative Kardiomyopathie: Altbekannt und dennoch gegenwärtig.

INTRODUCTION: Numerous cases of bovine dilatative cardiomyopathy (BDCMP) were registered in the nineteen-eighties, but the prevalence decreased steadily thanks to classical selection measures, i.e. excluding putative carrier animals from breeding. The cases described here show that the recessively inherited disease is still present in the Swiss cattle population. By use of a direct gene test developed a few years ago, a clinical tentative diagnosis can be confirmed. Since the end of the year 2016, carriers are officially labelled as such in Switzerland. Currently, about 2% of the insemination sires of the Holstein, Red Holstein and Swiss Fleckvieh breeds carry the causative mutation in the OPA3 gene. A combination of increased awareness of the disease and use of the gene test should allow for complete elimination of the disease from the Swiss cattle population.

INTRODUCTION: De nombreux cas de cardiomyopathie dilatative bovine (CMPDB) ont été rapportés dans les années 1980. Leur prévalence a ensuite fortement diminué grâce à des mesures classiques de sélection, à savoir l'exclusion de l'élevage des porteurs potentiels. Les cas décrits ici montrent que cette maladie héréditaire récessive, quoique rare, est toujours bien présente dans la population bovine suisse. Un test génétique direct développé il y a quelques années permet de confirmer définitivement un diagnostic de suspicion clinique. Depuis fin 2016, les porteurs de la mutation sont signalés officiellement en Suisse: environ 2% des taureaux d'insémination des races Holstein, Red Holstein et tachetée rouge sont porteurs de la mutation causative du gène OPA3. Une attention augmentée et un usage accru du test génétique rendent possible pour la première fois une éradication complète de la maladie du cheptel bovin suisse.