[Outcome of selective mating in the Entlebucher Mountain Dog for reduction of ureteral ectopia]. / Ergebnis der selektiven Verpaarung beim Entlebucher Sennenhund zur Reduktion der ureteralen Ektopie.

INTRODUCTION: The Entlebucher Mountain Dog is predisposed to ureteral ectopia and associated diseases of the urinary tract as well as the kidneys, which can have severe to lethal consequences. Due to the clustered occurrence of clinical signs in 11 % of Entlebucher Mountain dogs in the absence of a genetic test for ureteral ectopia, screening was introduced in 2008 to allow phenotype-based breeding selection. The ureteral orifices of the dogs are visualized by ultrasound and existing urinary retention or urinary incontinence is documented. The diagnostic findings were evaluated centrally with assignment to one of five phenotypes depending on the localization of the ureteral orifices and the renal and ureteral shape. Breeding approval and mating restrictions are the responsibility of the respective breeding associations and predominantly Entlebucher Mountain Dogs with extravesical ectopic ureters and/or clinical signs were excluded from breeding. The effect of phenotype-based selective mating on the incidence of ureteral ectopia and its clinical signs, as well as possible factors influencing the expression of the phenotype, were determined in the birth cohorts after the introduction of screening. Analysis of the data set of 1456 phenotyped Entlebucher Mountain Dogs showed, that at 11 % versus 5 %, males were more frequently assigned to the extravesical phenotype than females. The effect of phenotype-based breeding selection was examined in a subpopulation consisting of phenotyped parents and their offspring (n = 876). The prevalence of the extravesical phenotype decreased from 24 % in the 2005 to 2007 birth cohorts to 1,4 % in the 2015 to 2017 birth cohorts. Since 2015 almost no Entlebucher Mountain Dogs with incontinence, hydroureter or hydronephrosis have been recorded. It was feared that the additional selection measures to control ureteral ectopia in the small Entlebucher Mountain Dog population would intensify the inbreeding increase. However, this has so far remained absent. Therefore, as long as no genetic test is available, it is recommended to continue phenotype-based breeding selection with exclusion of dogs with extravesical ureteral ectopia and/or hydroureter/hydronephrosis/urinary incontinence, while keeping an eye on the development of the inbreeding coefficient.

INTRODUCTION: Le Bouvier de l'Entlebuch est prédisposé à l'ectopie urétérale et aux maladies associées des voies urinaires ainsi que des reins, ce qui peut entraîner des conséquences fatales. En raison de l'apparition de signes cliniques chez 11 % des chiens et en l'absence d'un test génétique pour l'ectopie urétérale, un dépistage a été introduit en 2008 pour permettre une sélection d'élevage basée sur le phénotype. Les orifices urétraux des chiens ont été visualisés par échographie et la rétention ou l'incontinence urinaire existante documentée. Les résultats du diagnostic ont été évalués de manière centralisée avec attribution à l'un des cinq phénotypes en fonction de la localisation des orifices urétéraux ainsi que de la forme des reins et des uretères. L'approbation pour la reproduction et les restrictions d'accouplement relèvent de la responsabilité des associations d'élevage respectives et les bouviers de l'Entlebuch présentant des uretères ectopiques extravésicaux et/ou des signes cliniques ont majoritairement été exclus de la reproduction. L'effet de cet accouplement sélectif basé sur le phénotype sur l'incidence de l'ectopie urétérale et de ses signes cliniques ainsi que les facteurs possibles influençant l'expression du phénotype ont été déterminés dans les cohortes de naissance après l'introduction du dépistage. L'analyse de l'ensemble des données de 1456 Bouviers de l'Entlebuch phénotypés a montré que, à 11 % contre 5 %, les mâles étaient plus fréquemment affectés au phénotype extravésical que les femelles. L'effet de la sélection d'élevage basée sur le phénotype a été examiné dans une sous-population composée de parents phénotypés et de leur progéniture (n = 876). La prévalence du phénotype extravésical est passée de 24 % dans les cohortes de naissance de 2005 à 2007 à 1,4 % dans les cohortes de naissance de 2015 à 2017. Depuis 2015, presque aucun bouvier d'Entlebuch présentant une incontinence, un hydrouretère ou une hydronéphrose n'a été enregistré. Une possible augmentation de la consanguinité due aux mesures de sélection supplémentaires visant à contrôler l'ectopie urétérale ne s'est pas produite. Par conséquent, tant qu'aucun test génétique n'est disponible, il est recommandé de poursuivre la sélection d'élevage basée sur le phénotype avec exclusion des chiens présentant une ectopie urétérale extravésicale et/ou une hydrouretère/hydronéphrose/incontinence urinaire, tout en surveillant l'évolution du coefficient de consanguinité.

[Prevalence of health problems in midlife Swiss warm-blooded horses]. / Auftreten gesundheitlicher Probleme beim Schweizer Warmblutpferd ­mittleren Alters.

INTRODUCTION: The breeding of a healthy horse is the basic requirement for optimal performance. This is also specifically stated in the breeding goal of the Swiss warmblood horse and should be achieved through a strict selection of the stallions. The aim of this retrospective study was to assess the current state of the population to optimize breeding. Data on the health status of Swiss warmblood horses in the age between 6 and 16 years (midlife) were collected by a telephone survey and analyzed descriptively. Following the heritability of the most common health problems were estimated. Data on 1,861 horses were collected between 2016 and 2018. Lameness (34%), colic (22%), sarcoids (19%), and pastern dermatitis (16%) were among the most common health problems, followed by back problems (13%), cough (10%), urticaria (10%), free fecal water syndrome (9%), nasal discharge (8%) and sweet itch (4%). Lameness was observed in 49% of the cases in the forelimbs, in 25% in the hindlimbs and in 26% in both. 27% of horses with colic have been hospitalized once and 8% have undergone colic surgery. Sarcoids became fewer or smaller in 89% of the treated and in 58% of the untreated horses. A significant relationship between treatment and the status of the sarcoids was demonstrated (p .

INTRODUCTION: L'élevage d'un cheval en bonne santé représente une condition de base pour une performance optimale. Ceci est également spécifiquement mentionné dans l'objectif d'élevage du cheval de sang suisse et doit être atteint par une sélection stricte des étalons. Afin d'optimiser l'élevage, il faut connaître l'état actuel de la population, ce qui était le but de cette étude rétrospective. Au moyen d'une enquête téléphonique, des données sur l'état de santé des chevaux de sang suisses âgés de 6 à 16 ans (âge moyen) ont été collectées et traitées de manière descriptive. Les héritabilités des problèmes de santé les plus courants ont ensuite été estimées. Au total, les données de1861 chevaux ont été collectés entre 2016 et 2018. Les boiteries (34%), les coliques (22%), les sarcoïdes (19%) et les crevasses (16%) figuraient parmi les problèmes de santé les plus courants, suivis des problèmes de dos (13%), de la toux (10%), des urticaires (10%), d'écoulements anaux (« Kotwasser ¼) (9%), d'écoulements nasaux (8%) et de dermite estivale (4%). Chez 49% des chevaux boiteux, il s'agissait d'une boiterie antérieure, chez 25% d'une boiterie postérieure et chez 26% d'une boiterie impliquant antérieurs et postérieurs. 27% des chevaux présentant des coliques avaient été hospitalisés et 8% avaient subi une chirurgie de coliques. Les sarcoïdes sont devenus moins nombreux ou plus petits chez 89% des chevaux traités mais également chez 58% des chevaux non traités. Une relation significative entre le traitement et l'état des sarcoïdes a pu être démontrée (p .

Association of missense variants in GDF9 with litter size in Entlebucher Mountain dogs.

In the past two decades, average litter size (ALS) in Entlebucher Mountain dogs decreased by approximately 0.8 puppies. We conducted a GWAS for ALS using the single-step methodology to take advantage of 1632 pedigree records, 892 phenotypes and 372 genotypes (173 662 markers) for which only 12% of the dogs had both phenotypes and genotypes available. Our analysis revealed associations towards the growth differentiation factor 9 gene (GDF9), which is known to regulate oocyte maturation. The trait heritability was estimated at 43.1%, from which approximately 15% was accountable by the GDF9 locus alone. Therefore, markers flanking GDF9 explained approximately 6.5% of the variance in ALS. Analysis of WGSs revealed two missense substitutions in GDF9, one of which (g.11:21147009G>A) affected a highly conserved nucleotide in vertebrates. The derived allele A was validated in 111 dogs and shown to be associated with decreased ALS (-0.75 ± 0.22 puppies per litter). The variant was further predicted to cause a proline to serine substitution. The affected residue was immediately followed by a six-residue deletion that is fixed in the canine species but absent in non-canids. We further confirmed that the deletion is prevalent in the Canidae family by sequencing three species of wild canids. Since canids uniquely ovulate oocytes at the prophase stage of the first meiotic division, requiring maturation in the oviduct, we conjecture that the amino acid substitution and the six-residue deletion of GDF9 may serve as a model for insights into the dynamics of oocyte maturation in canids.

Genome-wide association study and heritability estimate for ectopic ureters in Entlebucher mountain dogs.

An ectopic ureter is a congenital anomaly which may lead to urinary incontinence and without a surgical intervention even to end-stage kidney disease. A genetic component contributes to the development of this anomaly in Entlebucher mountain dogs (EMD); however, its nature remains unclear. Using the Illumina CanineHD bead chip, a case-control genome-wide association study was performed to identify SNPs associated with the trait. Six loci on canine chromosomes 3, 17, 27 and 30 were identified with 16 significantly associated SNPs. There was no single outstanding SNP associated with the phenotype, and the association signals were not close to known genes involved in human congenital anomalies of the kidney or lower urinary tract. Additional research will be necessary to elucidate the potential role of the associated genes in the development of ectopic ureters in the EMD breed.

Factors influencing litter size and puppy losses in the Entlebucher Mountain dog.

A good reproductive performance is a central element of animal breeding. The breeders of Entlebucher Mountain dogs observed a decrease of the mean litter size and an increase of the number of unsuccessful matings in the past years. The aim of the present study was to identify factors with an influence on fertility in this breed. In total, 915 litters from 202 sires and 348 dams from 1986 to 2013 entered the analyses. The total puppy losses (7.4%) reduced the mean litter size at birth of 5.49 ± 2.13 to a mean litter size at registration of 5.08 ± 2.05. There was no deviation from the expected equal sex distribution for puppies at birth and at registration, as well as for puppy losses consisting of stillborn puppies and puppies which died or had to be euthanized before registration. The mean annual litter inbreeding coefficient increased from 0.37 in 1986 to 0.40 in 2013 and was correlated with the year of birth of the litter (Kendall's tau b = 0.46). The age of the dam and parental inbreeding were identified as significant predictors with a negative effect on litter size at birth. For the litter size at registration the age and inbreeding of the dam had a significant negative effect and a 1% increase of dam inbreeding is expected to decrease the litter size at birth and registration by 0.1 and 0.09 puppies, respectively. The occurrence of total puppy losses decreased during the years and was more frequent in larger litters. In addition, in litters of older parents the occurrence of puppy losses was more frequent than in litters from younger parents. The final generalized linear mixed-effects models for litter size at birth, litter size at registration and for total puppy losses explained 36%, 33% and 22% of the total variance, respectively. The impact of inbreeding and parental age on fertility of the Entlebucher Mountain dog was small and the influence of the dam was much bigger than the one of the sire. Other factors must be responsible for the variability of litter sizes not explained by the models. Without changes of breeding circumstances, a further increase of inbreeding must be expected. Therefore, a close monitoring and minimizing of inbreeding must be followed up by the breeding community.

Heritabilities of health traits in Swiss Warmblood horses.

REASONS FOR PERFORMING STUDY: There is a lack of evidence regarding genetic parameters of health traits in Swiss Warmblood horses. OBJECTIVES: To estimate heritabilities of equine sarcoid disease, horn quality of hooves, prognathism and increased filling of talocrural joints as a possible indicator for osteochondrosis in Swiss Warmblood horses examined at the field tests for 3-year-olds between 2005 and 2013. STUDY DESIGN: Retrospective analysis of breed society database. METHODS: Swiss Warmblood horses were examined clinically by 13 veterinarians at field tests in Switzerland between 2005 and 2013. The presence of sarcoids, horn quality of the hooves, incisor occlusion and increased joint filling were assessed and recorded. Records of 3715 horses were integrated in a pedigree comprising 217,282 horses. Variance components and heritabilities were estimated on the liability scale using multiple-trait Gibbs sampler for animal models (MTGSAM). RESULTS: The prevalences of the examined traits were rather low ranging from 2.4 to 13.0%. Heritabilities estimated were 0.21 ± 0.07 for the occurrence of sarcoids, 0.04 ± 0.02 for hooves with markedly brittle and friable horn quality, 0.03 ± 0.01 for hooves with marked growth ring formation, 0.06 ± 0.03 for prognathism and 0.08 ± 0.04 for increased filling of the talocrural joint (an indicator of possible osteochondrosis). The influence of the examiner on the variance of these observations was considerable. CONCLUSIONS: With the exception of equine sarcoid disease, estimates for the heritabilities for the traits examined here were low. A standardised examination protocol may reduce the variance due to the examiner.

A single prolonged milking interval of 24h compromises the well-being and health of dairy Holstein cows.

Cows are often shown at dairy shows with overfilled udders to achieve a better show placing. However, it is unclear to what degree "over-bagging" affects the health and well-being of show cows. The goal of this study was to assess the effect of a single prolonged milking interval (PMI) of 24h on the measurable signs of health and well-being in dairy cows in early and mid-lactation and to assess the effect of a nonsteroidal anti-inflammatory drug (NSAID) on well-being during a PMI. Fifteen Holstein cows were studied in early lactation (89.5±2.7d in milk) and were given an NSAID or physiological saline in a crossover design. Ten cows were studied again in mid-lactation (151.6±4.0d in milk). Data on clinical signs of cows' health, behavior, and well-being were collected at 1 or 2h intervals before and during a PMI of 24h. Data from the last 6h of a 12h milking interval were compared with the last 6h of the PMI. Compared with that of a cow in the last 6h of a 12-h milking interval, the behavior of cows in early lactation (saline group) changed during the last 6h of the PMI: we observed decreased eating time (22.4 vs. 16.2min/h), increased ruminating time (13.3 vs. 25.0min/h), and increased hind limb abduction while walking (score 41.7 vs. 62.6) and standing (31.2 vs. 38.9cm). Udder firmness was increased (2.9 vs. 4.5kg) during this period and more weight was placed on the hind limbs (46.4 vs. 47.0%). We also found pathological signs at the end of the PMI: all cows showed milk leaking, and 10 of 15 cows developed edema in the subcutaneous udder tissue. Somatic cell count was significantly increased from 12h to 72h after the PMI. Administration of an NSAID had no influence on measured variables, except that the occurrence of edema was not significantly increased during PMI in the flunixin group (10 of 15 and 6 of 15 cows for the saline and flunixin groups, respectively). In the cows in mid-lactation, different variables were not significantly changed in the PMI compared with baseline values (e.g., eating and ruminating time, occurrence of edema, and abduction). We conclude that the cows' health and well-being were compromised by a single PMI of 24h, because their behavior changed and pathological signs were recorded. Administration of an NSAID had a slight effect on cows' well-being during a PMI. The stage of lactation had more effect on the cows' health and well-being, because fewer variables were changed in mid-lactation.

Increased FOXP3 expression in tumour-associated tissues of horses affected with equine sarcoid disease.

Recent studies suggest that regulatory T cells (Tregs) are associated with disease severity and progression in papilloma virus induced neoplasia. Bovine papilloma virus (BPV) is recognised as the most important aetiological factor in equine sarcoid (ES) disease. The aim of this study was to compare expression levels of Treg markers and associated cytokines in tissue samples of ES-affected equids with skin samples of healthy control horses. Eleven ES-affected, and 12 healthy horses were included in the study. Expression levels of forkhead box protein 3 (FOXP3), interleukin 10 (IL10), interleukin 4 (IL4) and interferon gamma (IFNG) mRNA in lesional and tumour-distant samples from ES-affected horses, as well as in dermal samples of healthy control horses were measured using quantitative reverse transcription polymerase chain reaction (PCR). Expression levels were compared between lesional and tumour-distant as well as between tumour-distant and control samples. Furthermore, BPV-1 E5 DNA in samples of ES-affected horses was quantified using quantitative PCR, and possible associations of viral load, disease severity and gene expression levels were evaluated. Expression levels of FOXP3, IL10 and IFNG mRNA and BPV-1 E5 copy numbers were significantly increased in lesional compared to tumour-distant samples. There was no difference in FOXP3 and cytokine expression in tumour-distant samples from ES- compared with control horses. In tumour-distant samples viral load was positively correlated with IL10 expression and severity score. The increased expression of Treg markers in tumour-associated tissues of ES-affected equids indicates a local, Treg-induced immune suppression.

Inheritance of porcine receptors for enterotoxigenic Escherichia coli with fimbriae F4ad and their relation to other F4 receptors.

Enteric Escherichia coli infections are a highly relevant cause of disease and death in young pigs. Breeding genetically resistant pigs is an economical and sustainable method of prevention. Resistant pigs are protected against colonization of the intestine through the absence of receptors for the bacterial fimbriae, which mediate adhesion to the intestinal surface. The present work aimed at elucidation of the mode of inheritance of the F4ad receptor which according to former investigations appeared quite confusing. Intestines of 489 pigs of an experimental herd were examined by a microscopic adhesion test modified in such a manner that four small intestinal sites instead of one were tested for adhesion of the fimbrial variant F4ad. Segregation analysis revealed that the mixed inheritance model explained our data best. The heritability of the F4ad phenotype was estimated to be 0.7±0.1. There are no relations to the strong receptors for variants F4ab and F4ac. Targeted matings allowed the discrimination between two F4ad receptors, that is, a fully adhesive receptor (F4adRFA) expressed on all enterocytes and at all small intestinal sites, and a partially adhesive receptor (F4adRPA) variably expressed at different sites and often leading to partial bacterial adhesion. In pigs with both F4ad receptors, the F4adRPA receptor is masked by the F4adRFA. The hypothesis that F4adRFA must be encoded by at least two complementary or epistatic dominant genes is supported by the Hardy-Weinberg equilibrium statistics. The F4adRPA receptor is inherited as a monogenetic dominant trait. A comparable partially adhesive receptor for variant F4ab (F4abRPA) was also observed but the limited data did not allow a prediction of the mode of inheritance. Pigs were therefore classified into one of eight receptor phenotypes: A1 (F4abRFA/F4acR+/F4adRFA); A2 (F4abRFA/F4acR+/F4adRPA); B (F4abRFA/F4acR+/F4adR-); C1 (F4abRPA/F4acR-/F4adRFA); C2 (F4abRPA/F4acR-/F4adRPA); D1 (F4abR-/F4acR-/F4adRFA); D2 (F4abR-/F4acR-/F4adRPA); E (F4abR-/F4acR-/F4adR-).

Inheritance of ectopic ureters in Entlebucher Mountain Dogs.

To test the hypothesis of a heritable base of ectopic ureters (EU) in Entlebucher Mountain Dogs (EMD) and to elucidate associated risk factors and mode of inheritance of the disease, 565 EMD were clinically investigated and population genetic analyses performed. Based on the location of the most caudal termination of the ureteral openings, 552 EMD were classified into three phenotype groups trigone, intravesically and extravesically ectopic based on results of abdominal sonography, urethra-cystoscopy and/or contrast-enhanced computed tomography. One-third (32.9%) of the phenotyped animals had normal terminations of both ureters in the bladder trigone, 47.3% had at least one intravesicular ectopic termination and 19.8% had at least one extravesicular ectopic termination. Multivariate mixed logistic regression revealed gender as a risk factor associated with EU as males were more often affected than females. Complex segregation analysis indicated a hereditary basis for EU in EMD and the involvement of a major gene in the occurrence of the extravesicular EU phenotype.

Genetic evidence of subaortic stenosis in the Newfoundland dog.

Subaortic stenosis (SAS) is a cardiac disorder with a narrowing of the descending aorta below the left ventricular outflow tract of the heart. It occurs in several species and breeds. The Newfoundland is one of the dog breeds where it is more common and usually leads to death at early adulthood. It is still discussed to which extent SAS has a genetic background and what its mode of inheritance could be. Extensive pedigree data comprising more than 230,000 Newfoundland dogs from the European and North American population reaching back to the 19th century including 6023 dogs with a SAS diagnosis were analysed for genetic factors influencing SAS affection. The incidence and prevalence of SAS in the analysed Newfoundland population sample were much higher than those reported in previous studies on smaller population samples. Assuming that some SAS-affected dogs remained undiscovered or were not reported, these figures may even be underestimated. SAS-affected Newfoundland dogs were more often inbred and closer related to each other than unaffected dogs, which is an indicator for a genetic background of SAS. The sex had no significant impact on SAS affectedness, pointing at an autosomal inheritance. The only simple mode of inheritance that fitted the data well was autosomal codominant with lethal homozygosity and a penetrance of 1/3 in the heterozygotes.

The interleukin 4 receptor gene and its role in recurrent airway obstruction in Swiss Warmblood horses.

Recurrent airway obstruction (RAO) in horses is the result of an interaction of genetic and environmental factors and shares many characteristics with human asthma. Many studies have suggested that the interleukin-4 receptor gene (IL4R) is associated with this disease, and a QTL region on chromosome 13 containing IL4R was previously detected in one of the two Swiss Warmblood families. We sequenced the entire IL4R gene in this family and detected 93 variants including five non-synonymous protein-coding variants. The allele distribution at these SNPs supported the previously detected QTL signal. Subsequently, we investigated IL4R mRNA expression in bronchoalveolar lavage fluid cells. During exacerbation, IL4R expression was increased in RAO-affected offspring in the implicated family, but not in the other family. These findings support that IL4R plays a role in some cases of RAO.

Replication and fine-mapping of a QTL for recurrent airway obstruction in European Warmblood horses.

Recurrent airway obstruction (RAO), or 'heaves', is a common performance-limiting allergic respiratory disease of mature horses. It is related to sensitization and exposure to mouldy hay and has a familial basis with a complex mode of inheritance. In a previous study, we detected a QTL for RAO on ECA 13 in a half-sib family of European Warmblood horses. In this study, we genotyped additional markers in the family and narrowed the QTL down to about 1.5 Mb (23.7-25.2 Mb). We detected the strongest association with SNP BIEC2-224511 (24,309,405 bp). We also obtained SNP genotypes in an independent cohort of 646 unrelated Warmblood horses. There was no genome-wide significant association with RAO in these unrelated horses. However, we performed a genotypic association study of the SNPs on ECA 13 in these unrelated horses, and the SNP BIEC2-224511 also showed the strongest association with RAO in the unrelated horses (p(raw) = 0.00037). The T allele at this SNP was associated with RAO both in the family and the unrelated horses. Thus, the association study in the unrelated animals provides independent support for the previously detected QTL. The association study allows further narrowing of the QTL interval to about 0.5 Mb (24.0-24.5 Mb). We sequenced the coding regions of the genes in the critical region but did not find any associated coding variants. Therefore, the causative variant underlying this QTL is likely to be a regulatory mutation.

Whole genome scan identifies several chromosomal regions linked to equine sarcoids.

Despite the evidence for a genetic predisposition to develop equine sarcoids (ES), no whole genome scan for ES has been performed to date. The objective of this explorative study was to identify chromosome regions associated with ES. The studied population was comprised of two half-sibling sire families, involving a total of 222 horses. Twenty-six of these horses were affected with ES. All horses had been previously genotyped with 315 microsatellite markers. Quantitative trait locus (QTL) signals were suggested where the F statistic exceeded chromosome-wide significance at P < 0.05. The QTL analyses revealed significant signals reaching P < 0.05 on equine chromosome (ECA) 20, 23 and 25, suggesting a polygenic character for this trait. The candidate regions identified on ECA 20, 23 and 25 include genes regulating virus replication and host immune response. Further investigation of the chromosome regions associated with ES and of genes potentially responsible for the development of ES could form the basis for early identification of susceptible animals, breeding selection or the development of new therapeutic targets.

Characterization of the porcine transferrin gene (TF) and its association with disease severity following an experimental Actinobacillus pleuropneumoniae infection.

Transferrin (TF)-mediated provision of iron is essential for a productive infection by many bacterial pathogens, and iron-depletion of TF is a first line defence against bacterial infections. Therefore, the transferrin (TF) gene can be considered a candidate gene for disease resistance. We obtained the complete DNA sequence of the porcine TF gene, which spans 40 kb and contains 17 exons. We identified polymorphisms on a panel of 10 different pig breeds. Comparative intra- and interbreed sequence analysis revealed 62 polymorphisms in the TF gene including one microsatellite. Ten polymorphisms were located in the coding sequence of the TF gene. Four SNPs (c.902A>T, c.980G>A, c.1417A>G, c.1810A>C) were predicted to cause amino acid exchanges (p.Lys301Ile, p.Arg327Lys, p.Lys473Glu, p.Asn604His). We performed association analyses using six selected TF markers and 116 pigs experimentally infected with Actinobacillus pleuropneumoniae serotype 7. The analysis showed breed-specific TF allele frequencies. In German Landrace, we found evidence for a possible association of the severity of A. pleuropneumoniae infection with TF genotypes.

Mixed inheritance of equine recurrent airway obstruction.

BACKGROUND: Mode of inheritance of equine recurrent airway obstruction (RAO) is unknown. HYPOTHESIS: Major genes are responsible for RAO. ANIMALS: Direct offspring of 2 RAO-affected Warmblood stallions (n = 197; n = 163) and a representative sample of Swiss Warmbloods (n = 401). METHODS: One environmental and 4 genetic models (general, mixed inheritance, major gene, and polygene) were tested for Horse Owner Assessed Respiratory Signs Index (1-4, unaffected to severely affected) by segregation analyses of the 2 half-sib sire families, both combined and separately, using prevalences estimated in a representative sample. RESULTS: In all data sets the mixed inheritance model was most likely to explain the pattern of inheritance. In all 3 datasets the mixed inheritance model did not differ significantly from the general model (P= .62, P= 1.00, and P= .27) but was always better than the major gene model (P < .01) and the polygene model (P < .01). The frequency of the deleterious allele differed considerably between the 2 sire families (P= .23 and P= .06). In both sire families the displacement was large (t= 17.52 and t= 12.24) and the heritability extremely large (h(2)= 1). CONCLUSIONS AND CLINICAL RELEVANCE: Segregation analyses clearly reveal the presence of a major gene playing a role in RAO. In 1 family, the mode of inheritance was autosomal dominant, whereas in the other family it was autosomal recessive. Although the expression of RAO is influenced by exposure to hay, these findings suggest a strong, complex genetic background for RAO.

[Genetics of recurrent airway obstruction (RAO)]. / Genetik der rezidivierenden Atemwegsobstruktion (RAO).

Recurrent airway obstruction (RAO) is a multifactorial and polygenic disease. Affected horses are typically 7 years of age or older and show exercise intolerance, increased breathing effort, coughing, airway neutrophilia, mucus accumulation and hyperreactivity as well as cholinergic bronchospasm. The environmental factors responsible are predominantly allergens and irritants in haydust, but the immunological mechanisms underlying RAO are still unclear. Several studies have demonstrated a familiar predisposition for RAO and it is now proven that the disease has a genetic basis. In offspring, the risk of developing RAO is 3-fold increased when one parent is affected and increases to almost 5-fold when both parents have RAO. Segregation analysis in two high-prevalence families demonstrated a high heritability and a complex inheritance with several major genes. A whole genomescan showed chromosome-wide significant linkage of seven chromosomal regions with RAO. Of the microsatellites, which were located near atopy candidate genes, those in a region of chromosome 13 harboring the IL4R gene were strongly associated with the RAO phenotype in the offspring of one RAO-affected stallion. Furthermore, IgE-levels are influenced by hereditary factors in the horse, and we have evidence that RAO-affected offspring of the same stallion have increased levels of specific IgE against moldspore allergens. The identification of genetic markers and ultimately of the responsible genes will not only allow for an improved prophylaxis, i.e. early identification of susceptible individuals and avoidance of high-risk matings, but also improve our ability to find new therapeutic targets and to optimize existing treatments.

Cryptorchidism and sex ratio are associated in dogs and pigs.

The objective of this study was to investigate whether the occurrence of cryptorchidism in a litter is associated with the sex ratio in this litter. The analysis included for dog 1,339 litters of 4 different breeds, of which 12.8% had 1 and 3.1% had 2 cryptorchids, and for pig 119,920 litters of 14 different populations, of which 2.2% had 1 and 0.2% had 2 cryptorchids. The data were analyzed using the GLIMMIX procedure of SAS. In dog, the presence of cryptorchids in a litter does not affect litter size or the stillborn rate. In pig, litter size increases significantly with an increasing number of cryptorchids in a litter. The stillborn rate in pig is larger in litters with cryptorchids than in litters without cryptorchids. To characterize the imbalance of the sexes in a litter, the sex ratio, defined as the number of live males divided by the number of live offspring, and the sex difference, defined as the number of live males minus the number of live females, were used as dependent variables in the analyses. In both dog and pig, the presence of 1 or 2 cryptorchids in a litter clearly goes together with a shift in both the sex ratio and the sex difference in a litter, in favor of male offspring. Our results in dog and pig suggest a common underlying mechanism affecting both cryptorchidism and sex ratio, which may hold true in other mammals as well.

Evaluation of the CTSL2 gene as a candidate gene for alopecia X in Pomeranians and Keeshonden.

Alopecia X is a noninflammatory, progressive, bilateral symmetric alopecia in dogs. The disease is mainly found in Nordic breeds. The breed predisposition and a strong familial accumulation suggest a hereditary background. We analyzed the cathepsin L2 gene (CTSL2) as a candidate for alopecia X. The comparative sequencing of 14 affected and 18 control animals revealed ten polymorphisms; however, none of these polymorphisms affected the coding sequence. Haplotype analysis did not reveal an association of one particular CTSL2 haplotype with the disease phenotype; therefore, we conclude that the CTSL2 gene is probably not the causative gene for alopecia X.