BackgroundCrossed beaks have been reported to occur in Appenzeller Barthuhn, a local Swiss chicken breed. The assumed causes for this beak deformity which are also seen in other bird species including domestic chickens, range from environmental influences to genetic factors. The aim of this project was to characterize the prevalence, the phenotype, and the underlying genetics of crossed beaks in Appenzeller Barthuhn chickens.ResultsThe estimated prevalence of 7% crossed beaks in Appenzeller Barthuhn was significantly higher compared to two other local Swiss chicken breeds. A breeding trial showed significantly higher prevalence of offspring with deformed beaks from mating of affected parents compared to mating of non-affected parents.Examination of 77 Appenzeller Barthuhn chickens with crossed beaks showed a variable phenotype presentation. The deviation of the beak from the median plane through the head ranged from 1° to 61°. In more than 60% of the cases, the upper and lower beak were bent in the same direction, whereas the remaining cases showed different forms of crossed beaks. Computed tomographic scans and bone maceration of the head of two chickens with crossed beaks revealed that the maxilla and the mandibula were affected, while other parts of the skull appeared to be normal.The gene LOC426217, a member of the keratin family, was postulated as a candidate gene for beak deformity in domestic chickens. Sequencing of the coding region revealed two significantly associated synonymous variants for crossed beaks in Appenzeller Barthuhn chickens. A genome-wide association study and a comparative analysis of runs of homozygosity based on high-density SNP array genotyping data of 53 cases and 102 controls showed no evidence of association.ConclusionsThe findings suggest a hereditary cause of crossed beaks in Appenzeller Barthuhn chickens. However, the observed variation in the phenotype, together with the inconclusive molecular genetic results indicates the need for additional research to unravel the genetic architecture of this beak deformity.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1398-z) contains supplementary material, which is available to authorized users.

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 (KIT PINZ ) 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 KIT PINZ variant occurs in some white spotted animals of the Swiss breeds Evol ener and Eringer. The introgression of the KIT PINZ 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.

This case report describes a new genetic disease of the Braunvieh breed in Switzerland. The bovine disorder also occurs in German Fleckvieh, and corresponds to human Fanconi-Bickel syndrome which is an inherited glycogen storage disease caused by mutations of the SLC2A2 gene encoding the glucose transporter GLUT2. This case report describes a single affected Original Braunvieh calf genotyped as homozygous for the FH2-associated SLC2A2 frame shift mutation. The clinical examination showed stunted growth, polyuria and polydipsia, as well as poor claw horn and coat quality. Necropsy revealed a pale cortex of the kidneys and a unilateral renal hypoplasia. Histology showed tubulonephrosis of the proximal tubules with protein- and glucose-rich contents. Glycogen accumulation was not evident in any organ. This finding is different from the reported lesions in two previously described GLUT2-deficient Fleckvieh heifers. In the presented case, growth retardation mainly seems to be associated with renal dysfunction. A direct gene test is available to eliminate the mutant allele from the population.

Background: Thrombocytopenia is an immune-mediated disease, which affects suckling piglets. Piglets are pale and inactive, show multiple hemorrhages and often die within days. Pathological examination reveals severe haemorrhages and oedema in several organs. Severe thrombocytopenia and elongated bleeding time characterize the disease haematologically. The sow produces antibodies against the thrombocyte antigens of the boar, which are present in the blood of the piglets. These isoimmune antibodies attack the platelets and megakaryocytes of the piglets, causing thrombocytopenia in succeeding matings of the same boar and sow. There is no known therapy against this condition. In the last few decades, the disease has become rare due to the increase of artificial insemination. Case presentation: On an organic breeding farm in Switzerland with a high percentage of natural pen matings, piglets of three litters showed haemorrhages on the skin, prolonged bleeding time and were generally in a reduced general state. A pathological examination revealed multifocal haemorrhages in the stomach, kidneys, dermis, mesenterium and spinal cord. Haematology showed a massive thrombocytopenia and regenerative anaemia. Due to these findings the diagnosis of thrombocytopenic purpura was established. To avoid further matings of the same boar and sow and thus more affected piglets, out of three possible boars the responsible sire had to be determined. This was achieved through array genotyping and subsequent computation of identity by descent and calculation of Mendelian errors for parentage verification. Thereby the responsible boar was identified and as a consequence removed from the farm. Further preventive measures, that had been established, included the recording of all matings and regular exchange of boars. Conclusion: The decreased number of natural matings with the surge of artificial insemination has probably reduced the number of cases of thrombocytopenic purpura and thus the disease awareness of farmers and veterinarians. However, as consumers wish for better animal welfare and higher ecological standards we may see a rise in natural matings and thus a return of the disease. In case of affected litters, genetic testing was proven a valid method for investigation and prevention of more cases and may be used more in the future.

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.