How and why dog owners select a specific breed may impact upon the health of the dog they acquire, and upon the wider health of the breed they select. Brachycephalic breeds are rapidly increasing in popularity despite increasing evidence linking brachycephalism with chronic and severe health conditions. This study used a questionnaire to explore pre-, during and post-purchase behaviours and attitudes of dog-owners who own popular brachycephalic dog breeds (n = 3 breeds) compared to popular non-brachycephalic dog breeds (n = 7 breeds). The survey received 1,427 valid responses. Brachycephalic breed owners were younger, more likely to live with children, and to be buying their chosen breed for the first time. The factor that most highly influenced brachycephalic owners’ decisions to buy their breed was appearance, followed by breed size suited to lifestyle, good dog breed for children and good companion breed. Perceived health of the breed was less influential in decision-making for brachycephalic owners compared to non-brachycephalic owners. The way in which owners acquired their dog differed by breed type, with brachycephalic owners more likely to use puppyselling websites to find their dog, less likely to see either parent of their puppy, and less likely to ask to see any health records. Despite many brachycephalic breed health issues being directly related to conformation, appearance remains the most significant determinant in why people desire these breeds. More targeted educational interventions are needed to change buyer attitudes and, if ineffective, other more direct mechanisms (eg legislation) may be required to protect canine welfare.

Selection for brachycephalic (foreshortened muzzle) phenotypes in dogs is a major risk factor for brachycephalic obstructive airway syndrome (BOAS). Clinical signs include respiratory distress, exercise intolerance, upper respiratory noise and collapse. Efforts to combat BOAS may be constrained by a perception that it is ‘normal’ in brachycephalic dogs. This study aimed to quantify owner-perception of the clinical signs of BOAS as a veterinary problem. A questionnaire-based study was carried out over five months on the owners of dogs referred to the Queen Mother Hospital for Animals (QMHA) for all clinical services, except for Emergency and Critical Care. Owners reported the frequency of respiratory difficulty and characteristics of respiratory noise in their dogs in four scenarios, summarised as an ‘owner-reported breathing’ (ORB) score. Owners then reported whether their dog currently has, or has a history of, ‘breathing problems’. Dogs (n = 285) representing 68 breeds were included, 31 of which were classed as ‘affected’ by BOAS either following diagnostics, or by fitting case criteria based on their ORB score, skull morphology and presence of stenotic nares. The median ORB score given by affected dogs’ owners was 20/40 (range 8-30). Over half (58%) of owners of affected dogs reported that their dog did not have a breathing problem. This marked disparity between owners’ reports of frequent, severe clinical signs and their perceived lack of a ‘breathing problem’ in their dogs is of concern. Without appreciation of the welfare implications of BOAS, affected but undiagnosed dogs may be negatively affected indefinitely through lack of treatment. Furthermore, affected dogs may continue to be selected in breeding programmes, perpetuating this disorder.

Reproductive traits have a major influence on the economic effectiveness of horse breeding. However, there is little information available. We evaluated the use of reproductive traits as selection criteria in official breeding programs to increase the reproductive efficiency of breeding studs, analysing 696 690 records from the pedigree data of eight Spanish horse populations, with different breeding purposes. The reproductive parameters studied in both sexes were age at first foaling (AFF), age at last foaling, average reproductive life and generational interval. In the females, the average interval between foaling (AIF) and interval between first and second foaling were also studied. There were clear differences between sexes and breeds, which may be due to management practices, breeding purposes and the status of the populations, rather than to differences in actual physiological conditions. Riding mares were the most precocious (AFF, 1937.64 to 2255.69 days) and had a more intensive reproductive use (AIF, 625.83 to 760.07 days), whereas sires used for meat production were the most precocious males (AFF, 1789.93 to 1999.75 days), although they had a shorter reproductive life (1564.34 to 1797.32 days). Heritabilities (0.02 to 0.42 in females and 0.04 to 0.28 in males) evidenced the genetic component of the reproductive traits, with Sport Horses having the higher average values. These results support the selection by AFF to improve reproductive aspects because of its medium–high heritability and its positive correlations with other important reproductive traits. The inclusion of the AIF is also recommended in sport populations, because this determines the length of the breaks between foaling and conditions the reproductive performance of the dams, as well as their selective intensity, genetic gain and genetic improvement. It is therefore an important economic parameter in breeding studs.

Conservation of animal genetic resources requires regular monitoring and interventions to maintain population size and manage genetic variability. This study uses genealogical information to evaluate the impact of conservation measures in Europe, using (i) data from the Domestic Animal Diversity Information System (DAD-IS) and (ii) a posteriori assessment of the impact of various conservation measures on the genetic variability of 17 at-risk breeds with a wide range of interventions. Analysis of data from DAD-IS showed that 68% of national breed populations reported to receive financial support showed increasing demographic trends, v. 51% for those that did not. The majority of the 17 at-risk breeds have increased their numbers of registered animals over the last 20 years, but the changes in genetic variability per breed have not always matched the trend in population size. These differences in trends observed in the different metrics might be explained by the tensions between interventions to maintain genetic variability, and development initiatives which lead to intensification of selection.

There are no estimates of the heritability of phenotypic udder traits in suckler sheep, which produce meat lambs, and whether these are associated with resilience to mastitis. Mastitis is a common disease which damages the mammary gland and reduces productivity. The aims of this study were to investigate the feasibility of collecting udder phenotypes, their heritability and their association with mastitis in suckler ewes. Udder and teat conformation, teat lesions, intramammary masses (IMM) and litter size were recorded from 10 Texel flocks in Great Britain between 2012 and 2014; 968 records were collected. Pedigree data were obtained from an online pedigree recording system. Univariate quantitative genetic parameters were estimated using animal and sire models. Linear mixed models were used to analyse continuous traits and generalised linear mixed models were used to analyse binary traits. Continuous traits had higher heritabilities than binary with teat placement and teat length heritability (h2) highest at 0.35 (SD 0.04) and 0.42 (SD 0.04), respectively. Udder width, drop and separation heritabilities were lower and varied with udder volume. The heritabilities of IMM and teat lesions (sire model) were 0.18 (SD 0.12) and 0.17 (SD 0.11), respectively. All heritabilities were sufficiently high to be in a selection programme to increase resilience to mastitis in the population of Texel sheep. Further studies are required to investigate genetic relationships between traits and to determine whether udder traits predict IMM, and the potential benefits from including traits in a selection programme to increase resilience to chronic mastitis.

A family history of dementia is associated with an increased risk of developing Alzheimer's disease (AD) late in life (LOAD). This study marked the first attempt to assess the familial contribution to differences in cognitive performance in a large family-based group in the Chinese community. We enrolled 168 participants without dementia from a single pedigree with 9 probable AD patients diagnosed after age 65. These participants were evaluated with a comprehensive neuropsychological battery, the Chinese version of the Mini Mental State Examination, and the Alzheimer Disease Assessment Scale–Cognitive Subscale. Analyses found that extended family members of the LOAD pedigree showed similar performance on measures of global cognitive function and semantic memory compared to controls, but lower scores on episodic memory, attention, and executive function measures. These results indicate that the genetic influences on certain sub-cognitive domains are more detectable despite normal global cognitive function, and that family members with the LOAD pedigree are at risk for developing LOAD by virtue of their family history with an additive risk due to increased age. The findings in this study support the importance of documenting if there is a positive family history of AD in clinical evaluations. (JINS, 2013, 19, 1–11)

Pedigree data from 11 267 animals born between 1960 and 2004 were used to analyse population structure and genetic variability of the Holstein–Friesian population in Kenya. Parameters estimated were the pedigree completeness index, average inbreeding coefficient, number of founders, effective number of founders and ancestors, and genetically important herds. The hierarchy of registered herds and concentration of origin of individuals was also assessed. Pedigree completeness of the reference population was 67.1 percent. Average inbreeding level for the entire population was 0.09 and 1.7 percent among individuals with three complete generations, and 9.2 percent among inbred individuals. Inbreeding level increased with generation from 0.8 to 2.5 percent in the most recent generation among individuals with three complete generations. Effective number of founders and ancestors were 156 and 108, respectively. The ten ancestors with the largest marginal genetic contribution accounted for 19.52 percent of the total variation. The effective number of genetically important herds that contributed breeding males to the population was 5.2. Higher levels of inbreeding were detected among individuals with at least three complete generations. Few herds contributed breeding males, causing structural weakness to the breeding programme. Recruitment of herds into the breeding tier is needed to strengthen the breeding structure and pedigree recording enhanced to enable long-term management of genetic variability.

The aim of this study was to explore genetic mechanisms of congenital heart disease by analysing family data. Families with two or more affected members were studied, and information on family history and risk factors was collected. A total of 25 families with congenital heart disease were identified, and among them the condition was confirmed in 57. The prevalence of congenital heart disease in first-degree relatives was 43.0%, that is 46 out of 107, significantly higher than that in second-degree relatives, that is, 4.4%, 11 out of 252) (χ2 = 83.897, P < 0.01). The prevalence difference between twins (90%) and siblings (62.2%) (χ2 = 4.983, P < 0.05) was also significant among first-degree relatives. Eleven families were found to have the same phenotype (44%), including ventricular septal defect in six families, atrial septal defect in two families, conotruncal defects in two families, and hypoplastic left heart syndrome in one family. Both twins were diagnosed with congenital heart disease in 8 out of 10 twin families – all eight twins were monozygotic. The cardiac phenotype of the twins was consistent in three families (37.5%). The cardiac phenotype of first- and second-degree relatives was not fully consistent with their probands. There was an increased incidence of threatened abortion in early pregnancy in patients with familial congenital heart disease when compared with sporadic congenital heart disease (χ2 = 8.704, P < 0.05). Morbidity in relatives was related to blood relationship, with a closer relationship increasing the risk of congenital heart disease. Genetic factors appear to play an important role in congenital heart disease.

An objective and accountable method is needed for deducing the number of registered animals in a breed from registration data. By following the principle that individual breeders register sufficient young females to be certain of having enough replacements for their current breeding stock, the ratios were calculated of the number of adult females in a breed to the number of female registrations, in a given year. Number of breeds considered were 8 cattle, 16 sheep, 8 pigs, 1 goat and 2 equines, all in the United Kingdom or Ireland. This yielded multipliers (4.4 for cattle, 3.3 for sheep, 3.1 for pigs, with confidence limits; and a point estimate of 5.2 for goats) enabling total adult female population to be predicted from a single year's registration data. There was considerable variation between breeds in values of the multiplier, apparently for reasons of breed history and function. This was particularly evident for equines where the two breeds yielded multipliers of 3.8 and 13.9. Multipliers, using registration data that are already in the public domain, can provide an estimate of breed numerical size, which a breed society can either accept or replace with an audited census.

Regulation of insurers' use of genetic information means actuaries are interested in age-at-onset of genetic disorders. Arjas & Haara (1984) suggested marked point processes (MPPs) as useful models for life history data with complex covariates. Age-at-onset distributions (or equivalently, hazard rates) in respect of inherited disorders are often estimated from pedigrees, which are life histories with unusually complex covariates, as well as strong dependencies induced by shared genes. Since Elston (1973) parametric models have often been used, conditioning the likelihood on known genotypes. However, a genotype identii ed by a presymptomatic genetic test is a form of internal covariate (Kalbfleisch & Prentice, 2002). We propose a very general MPP model of a pedigree, including presymptomatic genetic testing, (‘the full model’) and show under what circumstances the partial model leading to Elston's likelihood is valid. In practice, pedigrees are often ascertained retrospectively. Many such events can be modelled by augmenting the natural filtration of the MPP. We show that, except in simple special cases, the partial model is no longer valid, and the resulting likelihoods appear to be intractable. In particular, ascertainment interacts even with independent censoring so that likelihoods no longer factorize. For one simple special case — studies of sibships — we generalise a classical result to age-at-onset data. We conclude that the study of genetic conditions with variable age at onset gains insights from the underlying principles of survival analysis in their modern form, but that great care is needed in translating epidemiological studies into actuarial models.

A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27 families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since 1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. A total of 155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging between 0% and 48% (P<0·01). Significantly different infection frequencies with T. gondii were also observed for different families and ranged between 0% and 100% (P<0·01). Although the actual cause of each abortion was not verified, a highly significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection in the same families (P<0·01). The data presented here raise further questions regarding the significance of congenital transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods in the future.

An experimental herd of Large White pigs was established in 1931 and maintained as a closed population until 1992. The complete -pedigree (410 boars and 916 sows) has been analysed to measure along the succesive cohorts of breeding animals: thefounder representation and allele survival, the evolution ofcoancestry and inbreeding and the components of inbreeding due to each founder. Inferences about genetic and phenotypic parameters and effects of dam and litter inbreeding on litter size were obtained, using Bayesian techniques, from 2612 litter records. A significant mean reduction of 0·27 piglets born and 0·39 live born for each 10% of litter inbreeding was found but also evidence of variation among founder lineages in inbreeding depression. Alleles contributing to inbreeding depression were descendent from specific founder lineages.

Parameters based on probabilities of gene origin were used to evaluate the genetic variability of four Austrian cattle breeds. Effective numbers of founders, ancestors and remaining founder genomes showed that all four populations investigated are rather small genetically. Effective numbers of remaining founder genomes were 94 for Simmental, 41 for Braunvieh (Brown Swiss), 32 for Pinzgauer and 21 for Grauvieh (Grey cattle, a small mountain breed). As the value of 94 for Simmental was rather large in comparison with estimates from other populations in previous studies, the effect of population structure was investigated. A cosine measure of similarity based on differences in individual founder contributions to different subpopulations was defined and used for analysis. Subpopulations defined by regions were clearly more distinct for Simmental than for Braunvieh. The size of the cosine values depended on the method of calculating founder contributions and was overestimated when choosing the method not accounting for drift and bottlenecks (effective number of founders).

The calculation of probabilities on pedigrees of arbitrary complexity is discussed for a basic model of transmission and penetrance (encompassing Mendelian inheritance, and certain environmental influences).

The structure of pedigrees, and the types of loops occurring, is discussed. Some results in graph theory are obtained and, using these, a recurrence relation derived for certain probabilities. The recursive procedure enables the successive peeling off of certain members of the pedigree, and the condensation of the information on those individuals into a function on a subset of those remaining. The underlying theory is set out, and examples given of the utilization of the resulting algorithm.