Emotion in dogs: Translational and transformative aspects

Kujala (2017) provides an excellent overview of most aspects of emotion in dogs; however, she does not cover a few fields of research that I think are also relevant to the topic. In this commentary, I discuss the current state of our knowledge regarding cognitive decline and behavioral disorders in dogs as potential models for human neurodegenerative disease and mental illness; how emotion and cognition in dogs interact with sex, gonadectomy, and sexual behavior; as well as the transformative potential of functional MRI imaging of the conscious dog brain in the study of comparative neurophysiology

Demographic factors associated with joint supplement use in dogs from the Dog Aging Project

Osteoarthritis (OA) is one of the most prevalent age-related chronic conditions that afflict companion dogs, and multiple joint supplements are available to prevent or treat OA, though the efficacy of these treatments is controversial. While the demographic factors that are associated with OA diagnosis are well established, the factors that are associated with joint supplement use are not as well studied. Using data collected from the Dog Aging Project, we analyzed owner survey responses regarding joint supplement administration and OA diagnosis for 26,951 adult dogs. In this cross-sectional analysis, logistic regression models and odds-ratios (OR) were employed to determine demographic factors of dogs and their owners that were associated with joint supplement administration. Forty percent of adult dogs in our population were given some type of joint supplement. Perhaps not surprisingly, dogs of older age, larger size, and those that were ever overweight were more likely to receive a joint supplement. Younger owner age, urban living, owner education, and feeding commercial dry food were associated with a reduced likelihood of administration of joint supplements to dogs. Interestingly, mixed breed dogs were also less likely to be administered a joint supplement (OR: 0.73). Dogs with a clinical diagnosis of OA were more likely to receive a joint supplement than those without a reported OA diagnosis (OR: 3.82). Neutered dogs were more likely to have a diagnosis of OA, even after controlling for other demographic factors, yet their prevalence of joint supplement administration was the same as intact dogs. Overall, joint supplement use appears to be high in our large population of dogs in the United States. Prospective studies are needed to determine if joint supplements are more commonly administered as a preventative for OA or after an OA clinical diagnosis

Inbreeding and fertility in Irish Wolfhounds in Sweden: 1976 to 2007

<p>Abstract</p> <p>Background</p> <p>Given that no influence of inbreeding on life expectancy could be demonstrated in Irish Wolfhounds in a previous study, it was decided to test the influence of inbreeding and other parameters on fertility in this breed.</p> <p>Methods</p> <p>The study was based on all Irish Wolfhound litters registered in Sweden between 1976 and 2007 (n = 822 litters) as provided by the Swedish Kennel Club (SKK) and combined with a pedigree database going back to 1862. Analyses were performed using linear regression in a Generalised Linear Model and other tests in the SAS system^®.</p> <p>Results</p> <p>Mean number of pups per litter was 6.01 ± 2.65, with a maximum of 13. There were no significant differences in either the number of litters or the number of pups between years of birth. Males were used for breeding at a significantly earlier age than females. Mean number of litters per parent was 2.96 ± 3.14 for males and 1.59 ± 0.87 for females. No influence of Wright's inbreeding coefficients over 5, 10, 20 and 30 generations and/or Meuwissen's inbreeding coefficients on litter size was detected. In the Generalised Linear Model, highly significant, but weak (coefficient of determination (R²) = 0.0341) influences were found for maternal age at mating as well as maternal inbreeding measured by Wright's inbreeding coefficient over 30 generations and Meuwissen's inbreeding coefficient. Paternal inbreeding coefficients over 5, 10, 20 and 30 generations and calculated after Meuwissen, as well as maternal inbreeding coefficients over 5, 10 and 20 generations did not have significant effects on litter size.</p> <p>Conclusion</p> <p>The low coefficient of determination (R²) value of the Generalised Linear Model indicates that inbreeding does not have a strong influence on fertility in Irish Wolfhounds, which is consistent with earlier results and the breed's genetic history. These results likely reflect the aforementioned genetic history and should not be extrapolated to other breeds without prior breed-specific research.</p

Lifespan of companion dogs seen in three independent primary care veterinary clinics in the United States

Abstract Background The privately owned companion dog is an emerging model in comparative medicine, notably because it shares the human environment including its risk factors, is affected by many analogous age-related diseases, receives comparable medical care, and has excellent veterinary medical data available. Past studies of dog lifespan have used academic, corporate or insurance data. While independent primary care data exist for the UK, none have as of yet been published for the US. This study analyzed data from three independent primary care US veterinary hospitals and identified factors that influence lifespan and mortality in a cohort of n = 20,970 privately owned dogs using Kaplan-Meier survival estimators and Cox Proportional Hazards modelling, including body size as a covariate. Results As previously reported, body size was negatively correlated with lifespan. Gonadectomy was associated with a longer lifespan, with the effect being stronger in females than in males. This lifespan advantage was conserved in gonadectomized female dogs that lived to at least ages 5 and 8 years. We did not find significant differences in lifespan between purebred and mixed breed dogs; however, breeds with larger effective population sizes and/or lower inbreeding coefficients had median survival times 3–6 months longer than breeds with smaller effective population sizes or higher inbreeding coefficients, indicating that these measures of genetic diversity may be affecting breed lifespans. We also found that dog breeds belonging to the “Mountain” ancestral group had median survival times that were 3.5–4.6 years shorter than other purebred dog groups, which remained significant even when correcting for body size. Conclusions Our findings show that it is possible to obtain and analyze data from independent veterinary clinics in the US, an approach that could be useful for studies of comparative epidemiology under the One Health and One Welfare paradigms. We also show that the lifespan effects of gonadectomy are not identical between the sexes and should be investigated separately by sex in future analyses. More research is needed to further clarify the influence of age at gonadectomy, as well as the factors leading to the observed differences in lifespan in the “Mountain” ancestral group and in dog breeds of varying inbreeding coefficients and effective population sizes