Selective breeding for desirable traits in strictly controlled populations has generated an extraordinary diversity in canine morphology and behaviour, but has also led to loss of genetic variation and random entrapment of disease alleles. As a consequence, specific diseases are now prevalent in certain breeds, but whether the recent breeding practice led to an overall increase in genetic load remains unclear. Here we generate whole genome sequencing (WGS) data from 20 dogs per breed from eight breeds and document a ~10% rise in the number of derived alleles per genome at evolutionarily conserved sites in the heavily bottlenecked cavalier King Charles spaniel breed (cKCs) relative to in most breeds studied here. Our finding represents the first clear indication of a relative increase in levels of deleterious genetic variation in a specific breed, arguing that recent breeding practices probably were associated with an accumulation of genetic load in dogs. We then use the WGS data to identify candidate risk alleles for the most common cause for veterinary care in cKCs–the heart disease myxomatous mitral valve disease (MMVD). We verify a potential link to MMVD for candidate variants near the heart specific NEBL gene in a dachshund population and show that two of the NEBL candidate variants have regulatory potential in heart-derived cell lines and are associated with reduced NEBL isoform nebulette expression in papillary muscle (but not in mitral valve, nor in left ventricular wall). Alleles linked to reduced nebulette expression may hence predispose cKCs and other breeds to MMVD via loss of papillary muscle integrity.

Objectives The aim of this study was to describe the characteristics and long-term outcome of surgically and conservatively treated cats with cranial cruciate ligament disease (CCLD). Methods A retrospective cohort study of cats with CCLD, diagnosed at two university animal hospitals between January 2011 and December 2016, was performed. Signalment, history, treatment and follow-up information were retrieved. Cat owners were contacted for additional long-term follow-up information. The cases were divided into two groups: one conservatively managed and one surgically treated with the lateral fabellotibial suture technique. A quality of life questionnaire, the Feline Musculoskeletal Pain Index (FMPI), was distributed to the owners of cats alive at follow-up for assessment of chronic pain as a long-term outcome. Univariable statistical methods were used to evaluate the data. Results Fifty cats were identified and were followed for a median of 41 months after diagnosis of CCLD. Seven cats (14%) developed bilateral CCLD. Twenty-eight cats (56%) were treated conservatively and 22 (44%) surgically. All surgically treated cats in which arthrotomy was performed (19/22) had total cranial cruciate ligament rupture and 9/19 (47%) had meniscal injuries. Postoperative surgical complications were recorded in 6/22 cats (27%). Owners of 24/29 (83%) cats still alive at follow-up completed the FMPI questionnaire. The conservatively treated cats had a lower FMPI score, indicating less chronic pain, than those cats treated surgically ( P = 0.017). Conclusions and relevance Conservatively treated cats with CCLD experienced less chronic pain at long-term follow-up than surgically treated cats. Bilateral disease is not uncommon in cats with CCLD.

Cruciate ligament rupture (CLR) is a common orthopedic disorder in dogs. The study objectives were to evaluate incidence rate (IR), cause-specific mortality rate (CSMR) and risk factors for CLR in insured dogs. A single cohort study of dogs insured in Agria Pet Insurance in Sweden (2011–2016) was performed. Age at diagnosis, IR, CSMR and relative risk (RR) for CLR was calculated overall and per breed. The cohort included just over 600,000 dogs. The IR of CLR was 23.8 (95% confidence interval, 23.1–24.6) cases per 10,000 DYAR. The breeds with highest RR of CLR were Boerboel and Dogo Canario, while the breeds with lowest RR were Standard Dachshund and Miniature Pinscher. Dogue de Bordeaux had highest RR of euthanasia due to CLR. The median age at veterinary care claim for CLR was 7.1 (range 0.3–16.0) years and 6.6 (0.3–12) years at life insurance settlement. Large and giant breeds were generally diagnosed and euthanized due to CLR at a younger age compared to smaller breeds. The majority of the breeds with increased RR of CLR diagnosis and CLR-related euthanasia were large or giant. A pattern of increasing size and decreasing age at diagnosis/CLR-related euthanasia was observed.

Background: Stifle joint diseases (SJD) are common in dogs and include a variety of diagnoses. The objective of the study was to provide an overview of the epidemiology of SJD in insured dogs. Methods: An historical single cohort study of dogs insured in Agria Pet Insurance (2011-2016) in Sweden was performed. Incidence and relative risk (RR) of SJD was calculated for the whole dog population and for subgroups divided by breed, breed group and sex. Results: The study population included almost 600,000 insured dogs (>1.7 million dog-years). Ninety-three different stifle joint diagnoses were reported in 9624 dogs, and the most common were cruciate ligament rupture and patellar luxation. The incidence of SJD was 55.4 cases per 10,000 dog-years at risk. Bulldog and boerboel had the highest RR of SJD. The breeds that accounted for the highest proportion of all SJD claimed dogs were mixed breed and Labrador retriever. Female dogs had a slightly increased RR compared with male dogs (RR 1.06, p = 0.006). The incidence increased yearly during the observation period. Conclusion: The study demonstrates breed-specific differences in incidence of SJD in dogs, which may be of importance for breeders, dog owners and veterinarians.

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