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Canine elbow dysplasia encompasses four developmental diseases: ununited anconeal process, osteochondrosis of the medial part of the humeral condyle, fragmented medial coronoid process (FCP), and incongruity of the elbow joint. Four radiographic views per joint were used to evaluate 2693 Labrador Retrievers (LRs), 1213 Golden Retrievers (GRs), and 974 Bernese Mountain Dogs (BMDs) for the presence of elbow dysplasia between 2002 and 2009 in the Netherlands. The views were also graded for signs of osteoarthritis and sclerosis. FCP was diagnosed most frequently in LRs, GRs and BMDs, with an incidence of 6%, 5%, and 15%, and a heritability of 0.17, 0.24, and 0.06, respectively. Heritabilities were estimated using a sire model and all available ancestors. Sclerosis at the base of the medial coronoid process was the radiographic sign most strongly correlated with FCP (r = 0.95, 0.92, and 0.95 in LRs, GRs and BMDs, respectively). The sex of the dog was significantly correlated with the presence of osteoarthritis in LRs, but not in GRs and BMDs. Male LRs were 1.7-fold more frequently, but not more severely, affected by osteoarthritis than female dogs. Age at radiographic examination was significantly associated with osteoarthritis in all three breeds. The heritability estimates in Retrievers were high enough to warrant including FCP findings in the breeding policy, but until the biomechanical and genetic background of elbow dysplasia are better understood, correct phenotyping with a sensitive technique is essential. [ABSTRACT FROM AUTHOR]

Background: The etiogenesis of congenital portosystemic shunt in dogs is not understood. In Irish Wolfhounds, intrahepatic portosystemic shunt (IHPSS) is thought to be hereditary, but the mode of inheritance is unknown. Objectives: To document the genetic background and investigate the potential mode of inheritance of IHPSS in Irish Wolfhounds. Animals: Three mature, privately owned, affected siblings and their progeny produced in 2 litters. Methods: Prospective, observational study. Two test matings of 1 affected sire with 2 of his affected sisters were used to determine the inheritance pattern. Affection status was determined by measuring venous blood ammonia concentrations, detection of the shunt by ultrasonography and confirmation during surgical attenuation of the intrahepatic shunting vessel. Results: In 1 litter of 5 pups all had an IHPSS. In the other litter 5 of 11 pups were affected. Both left- and right-sided shunts occurred in both litters. No sex predisposition was evident among affected dogs. Conclusions and Clinical Importance: Our results show that IHPSS in Irish Wolfhounds is a familial disorder that is likely genetic. It is unlikely that the mode of inheritance is monogenic. A digenic, triallelic trait could explain the observed occurrence of IHPSS but other modes of inheritance cannot be excluded. [ABSTRACT FROM AUTHOR]

To improve the health status (resilience) of dairy cows, levels of natural antibodies (NAb) might be useful. The objective of the present study was to compare levels and to estimate genetic parameters for NAb measured in milk and plasma samples. Titers of NAb IgM and IgG isotype-binding keyhole limpet hemocyanin of 2,919 cows, in both plasma and milk, were measured using ELISA. Analysis revealed that NAb levels in milk significantly increased with parity, whereas they remained constant in plasma. Moderate positive phenotypic correlations were found between NAb levels in milk and in plasma: 0.18 for IgG and 0.40 for IgM. This indicates that NAb from milk and plasma might reflect different aspects of dairy cow health status. However, high genetic correlations were found for NAb in milk and plasma: 0.81 for IgG and 0.79 for IgM. Heritabilities (SE in parentheses) for NAb measured in plasma [0.15 (0.05) for IgG and 0.25 (0.06) for IgM] were higher than heritabilities of NAb measured in milk [0.08 (0.03) for IgG and 0.23 (0.05) for IgM]. Our results indicate that NAb measured in milk and plasma are heritable and likely have a common genetic background, suggesting that NAb levels measured in milk might be useful for genetic improvement of disease resistance. [ABSTRACT FROM AUTHOR]

The objective of this study was to model genetic selection for Johne's disease resistance and to study the effect of different selection strategies on the prevalence in the dairy cattle population. In the Netherlands, a certification-and-surveillance program is in use to reduce prevalence and presence of sources of infection in milk by culling ELISA-positive dairy cows in infected herds. To investigate the additional genetic effect of this program, a genetic-epidemiological model was developed to assess the effect of selection of cows that test negative for Johne's disease (dam selection). The genetic effect of selection at the sire level was also considered (sire selection), assuming selection of 80% of sires producing the most resistant offspring based on their breeding values, as well as the combined effect. Parameters assumed to be affected by genetic selection were the length of the latent period, susceptibility (i.e., the number of infectious doses needed to become infected), or the length of susceptible period as a calf. The effect of selection was measured by the time in years required to eliminate infection. Sensitivity analysis was performed for heritability, accuracy of selection, and intensity of selection. For dam selection, responses to selection were small, requiring 379 to 702 yr for elimination. For sire selection, responses were much larger, although elimination still required 147 to 223 yr. The response to selection was largest if genetic selection affected the length of the susceptible period, followed by the susceptibility, and finally the length of the latent period. Genetic selection for Johne's disease resistance by certification and surveillance is too slow for practical purpose, but that selection on the sire level is able to contribute to the control of Johne's disease in the long run. [ABSTRACT FROM AUTHOR]

Classical control strategies based on management restrictions to reduce transmission, culling of infected goats, and vaccination have not been able to eradicate Johne's disease from infected herds. Selective breeding for less susceptibility to disease may be a useful additional tool to contribute to control of the disease. The aim of this study was to estimate genetic variation and heritability for infection status as determined by a specific antibody response against Mycobacterium avium subspecies paratuberculosis in milk of Dutch dairy goats. Milk samples from 950 goats were tested for antibodies specific to Johne's disease by ELISA on 5 consecutive test days, with a time interval of around 3 mo. Test results were coded as infected or not infected according to the instructions of the manufacturer. Heritability of infection status was estimated for 3 data sets to determine the effect of repeated sampling: only test results obtained on the first test day (first-test); the maximum test result of each animal obtained on 1 of the 5 test days (max-test); and all test results per animal, with a maximum of 5 consecutive samplings (alltest). Data sets first-test and max-test were analyzed with a sire model with fixed effects for year of birth and stage of lactation, and random effects for sire and error. For data set all-test, an additional permanent environment effect was included in the model. The estimated heritability on the underlying scale ranged from 0.12 in data set first-test, to 0.09 in data set max-test, to 0.07 in data set all-test. [ABSTRACT FROM AUTHOR]

Heritability of susceptibility to Johne's disease in cattle has been shown to vary from 0.041 to 0.159. Although the presence of genetic variation involved in susceptibility to Johne's disease has been demonstrated, the understanding of genes contributing to the genetic variance is far from complete. The objective of this study was to contribute to further understanding of genetic variation involved in susceptibility to Johne's disease by identifying associated chromosomal regions using a genome-wide association approach. Log-transformed ELISA test results of 265,290 individual Holstein-Friesian cows from 3,927 herds from the Netherlands were analyzed to obtain sire estimated breeding values for Mycobacterium avium subspecies paratuberculosis (MAP)-specific antibody response in milk using a sire-maternal grandsire model with fixed effects for parity, year of birth, lactation stage, and herd; a covariate for milk yield on test day; and random effects for sire, maternal grandsire, and error. For 192 sires with estimated breeding values with a minimum reliability of 70%, single nucleotide polymorphism (SNP) typing was conducted by a multiple SNP analysis with a random polygenic effect fitting 37,869 SNP simultaneously. Five SNP associated with MAP-specific antibody response in milk were identified distributed over 4 chromosomal regions (chromosome 4, 15, 18, and 28). Thirteen putative SNP associated with MAP-specific antibody response in milk were identified distributed over 10 chromosomes (chromosome 4, 14, 16, 18, 19, 20, 21, 26, 27, and 29). This knowledge contributes to the current understanding of genetic variation involved in Johne's disease susceptibility and facilitates control of Johne's disease and improvement of health status by breeding. [ABSTRACT FROM AUTHOR]

Patellar luxation (PL) is one of the major hereditary orthopaedic abnormalities observed in a variety of dog breeds. When the patellae move sideways out of the trochlear groove, this is called PL. The PL score varies between dogs from normal to very severe. Reducing the prevalence of PL by breeding could prevent surgery, thereby improve welfare. Orthopaedic specialists differentiate between normal and loose patellae, where the patellae can be moved to the edge of the trochlear groove, considering scoring loose patellae as normal in the future. Loose patellae are considered acceptable for breeding so far by the breeding organization. The aim of this study was to analyse the genetic background of PL to decide on the importance of loose patellae when breeding for healthy dogs. Data are available from two dog breeds, that is Flat-coated Retrievers (n = 3808) and Kooiker dogs (n = 794), with a total of 4602 dogs. Results show that loose patellae indicate that dogs are genetically more susceptible to develop PL because family members of the dogs with loose patellae showed more severe PL. In addition, the estimated breeding values for dogs with loose patellae indicate that breeding values of dogs with loose patellae were worse than breeding values obtained for dogs with a normal score. Given these results, it is advised to orthopaedic specialists to continue to score loose patellae as a separate class and to dog breeders to minimize the use of dogs in breeding with a genetically higher susceptibility for PL., (© 2015 Blackwell Verlag GmbH.)

The prevalence of patellar luxation (PL) and genetic factors potentially involved in the disorder were investigated in Dutch Kooiker dogs. A cohort of 842 Kooiker dogs, the offspring of 195 sires and 318 dams, was screened for PL from 1994 to 2011. The cohort was included in a pedigree of 1737 Kooiker dogs comprising nine generations. PL was present in 24% of screened dogs, with unilateral and bilateral luxation being observed equally frequently. Medial PL was more common (61%) than lateral PL (32%) or bidirectional PL (7%). The frequency of PL was similar in male and female dogs, with a female:male relative risk of 1.15 (95% confidence interval, CI, 0.90-1.48). The heritability of PL in the screened population was 0.27 ± 0.07. Since the start of the screening programme, the prevalence of PL decreased from 28% to 19%. A genome-wide association study of PL with 48 cases and 42 controls suggested the possible involvement of a region on chromosome 3 (Praw = 1.32 × 10(-)(5), Pgenome = 0.142), but the involvement of this region could not be confirmed in a validation group. Breeding programmes for complex diseases, such as PL, would benefit from combining pedigrees, phenotypes and genotypes, i.e. from genomic selection, as is currently the method of choice for breeding of production animals., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Hip as well as elbow dysplasia (HD, ED) are developmental disorders leading to malformation of their respective joints. For a long time both disorders have been scored and targeted for improvement using selective breeding in several Dutch dog populations. In this paper all scores for both HD and ED, given to pure bred dogs in the Netherlands from 2002 to 2010, were analyzed. Heritabilities and correlations between HD and ED were calculated for the 4 most frequently scored breeds. Heritabilities ranged from 0.0 to 0.37 for HD related traits (FCI-score, osteoarthritis, congruity, shape and laxity (Norberg angle); FCI: Fédération Cynologique Internationale) and from 0.0 to 0.39 for ED related traits (IEWG score, osteoarthritis, sclerosis and indentation; IEWG: International Elbow Working Group). HD related traits showed high genetic and residual correlations among each other but were only to a minor extent correlated with ED related traits, which also showed high correlations among each other. Genetic correlations were higher than residual correlations. Phenotypic and genetic trends since 2001 for the four most scored breeds were slightly positive but decreasing over time, indicating that selection over the past decade has not been effective., (Copyright © 2014. Published by Elsevier B.V.)

Failure of the timely expulsion of the fetal membranes, called retained placenta, leads to reduced fertility, increased veterinary costs and reduced milk yields. The objectives of this study were to concurrently look at the heritable and non-heritable genetic effects on retained placenta and test the hypothesis that a greater coefficient of relationship between dam and calf increases the risk of retained placenta in the dam. The average incidence of retained placenta in 43,661 calvings of Meuse-Rhine-Yssel cattle was 4.5%, ranging from 0% to 29.6% among half-sib groups. The average pedigree based relationship between the sire and the maternal grandsire was 0.05 and ranged from 0 to 1.04. Using a sire-maternal grandsire model the heritability was estimated at 0.22 (SEM=0.07) which is comparable with estimates for other dual purpose breeds. The coefficient of relationship between the sire and the maternal grandsire had an effect on retained placenta. The coefficient of relationship between the sire and the maternal grandsire was used as a proxy for the coefficient of relationship between dam and calf, which is correlated with the probability of major histocompatibility complex (MHC) class I compatibility between dam and calf. MHC class I compatibility is an important risk factor for retained placenta. Although the MHC class I haplotype is genetically determined, MHC class I compatibility is not heritable. This study shows that selection against retained placenta is possible and indicates that preventing the mating of related parents may play a role in the prevention of retained placenta., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A better understanding of the biodiversity of Mycobacterium avium subsp. paratuberculosis (MAP) offers more insight in the epidemiology of paratuberculosis and therefore may contribute to the control of the disease. The aim of this study was to investigate the genetic diversity in bovine MAP isolates using PCR-based methods detecting genetic elements called Variable-Number Tandem Repeats (VNTRs) and Mycobacterial Interspersed Repetitive Units (MIRUs) to determine if multiple MAP strains can coexist on farms with endemic MAP infection. For 52 temporal isolates originating from infected cattle from 32 commercial dairy herds with known trading history, MIRU-VNTR analysis was applied at 10 loci of which six showed variation. Within the group of 52 isolates, 17 different MIRU-VNTR patterns were detected. One MIRU-VNTR pattern was found in 29 isolates, one pattern in four isolates, one pattern in three isolates, two times one MIRU-VNTR pattern was found occurring in two isolates, and 12 patterns were found only once. Eleven herds provided multiple isolates. In five herds a single MIRU-VNTR pattern was detected among multiple isolates whereas in six herds more than one pattern was found. This study confirms that between dairy farms as well as within dairy farms, infected animals shed MAP with different MIRU-VNTR patterns. Analysis of trading history and age within herds indicated that cows born within the same birth cohort can be infected with MAP strains exhibiting variations in the number of MIRU-VNTR repeats. These data indicate that such multiple genotypes of MAP can coexist within one herd., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Worldwide, classical control strategies based on hygiene and culling of infected animals have been implemented to eradicate Johne's disease. Breeding for disease resistance may be a useful additional tool to control the disease. The aim of this study was to estimate genetic parameters for the presence of a Mycobacterium avium ssp. paratuberculosis specific antibody response in milk of Dutch Holstein-Friesian cows using subsets of data based on within-herd test prevalence. The analyzed data set consisted of milk samples of 684,364 animals from 12,077 herds collected during the routine milk production scheme. Milk samples were tested for antibodies specific for Johne's disease by an ELISA test. Heritability estimates were calculated for 4 different subsets of data to determine the sensitivity of heritability for within-herd test prevalence. Results expressed as percentage of the sample to positive ratio were analyzed with a sire-maternal grandsire model with fixed effects for parity, year of birth, lactation stage, and herd; a covariate for milk yield at test day; and random effects for sire, maternal grandsire, and error. The estimated heritability ranged from 0.031 for the complete data set to 0.097 for herds with a test prevalence of at least 10%. Cross-validation was applied to determine which of the subsets of data produced the most accurate estimated breeding values. Results showed that for genetic selection to contribute to disease control, breeding values were estimated most accurately from herds with at least 2 animals that tested positive. In this subset the heritability was 0.041., (Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Reasons for Performing Study: It is expected that climate and habitat factors influence the prevalence of culicoides and, therefore, the prevalence of insect bite hypersensitivity (IBH), but very little is described in the literature to prove the association of these factors. Prevalence varies widely from 3% in certain areas of Great Britain to 60% in certain parts of Australia., Objectives: To describe the influence of environmental factors on the prevalence of IBH in Shetland ponies and Friesian horses in The Netherlands., Methods: Data on 3284 Shetland and 2824 Friesian mares (n = 6108) were collected in The Netherlands, based on 90 regions, according to postal codes. The climate components, amount of rainfall, number of warm days, number of cold days, and habitat components of soil type and type of vegetation were collected for each region., Results: Prevalence of IBH varied widely from 0-71.4% per region. The results showed that the environment with low IBH-prevalence had high rainfall, many cold days and few warm days per year. Habitats with a low IBH-prevalence were based along the coast line. Habitats with increasing prevalence of IBH had soils of clay with heather and woody vegetation. Friesian mares had a higher IBH prevalence than Shetland mares, which could indicate an effect of genetic background or an effect of year., Conclusions: There is an environmental effect on IBH prevalence within The Netherlands, which is caused by climate and habitat factors., Potential Relevance: The results provide a more accurate description of environmental factors and their impact on development of IBH; and should help better to understand habitat and climate effects, and to distinguish these from other effects, such as animal factors (genetics, age or sex).