The effect of inbreeding, body size and morphology on health in dog breeds

Danika Bannasch; Thomas Famula; Jonas Donner; Heidi Anderson; Leena Honkanen; Kevin Batcher; Noa Safra; Sara Thomasy; Robert Rebhun

doi:10.1186/s40575-021-00111-4

The effect of inbreeding, body size and morphology on health in dog breeds

Canine Med Genet. 2021 Dec 2;8(1):12. doi: 10.1186/s40575-021-00111-4.

Authors

Danika Bannasch¹, Thomas Famula², Jonas Donner³, Heidi Anderson³, Leena Honkanen³, Kevin Batcher⁴, Noa Safra^{4

5}, Sara Thomasy^{6

7}, Robert Rebhun⁶

Affiliations

¹ Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA. dlbannasch@ucdavis.edu.
² Department of Animal Science, University of California-Davis, Davis, CA, 95616, USA.
³ Wisdom Health Genetics, Kinship, FI-00290, Helsinki, Finland.
⁴ Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.
⁵ Zoetis, Parsippany, NJ, USA.
⁶ Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.
⁷ Department of Ophthalmology & Vision Science, School of Medicine, University of California-Davis, Davis, CA, 95616, USA.

Abstract

Background: Dog breeds are known for their distinctive body shape, size, coat color, head type and behaviors, features that are relatively similar across members of a breed. Unfortunately, dog breeds are also characterized by distinct predispositions to disease. We explored the relationships between inbreeding, morphology and health using genotype based inbreeding estimates, body weight and insurance data for morbidity.

Results: The average inbreeding based on genotype across 227 breeds was F_adj = 0.249 (95% CI 0.235-0.263). There were significant differences in morbidity between breeds with low and high inbreeding (H = 16.49, P = 0.0004). There was also a significant difference in morbidity between brachycephalic breeds and non-brachycephalic breeds (P = 0.0048) and between functionally distinct groups of breeds (H = 14.95 P < 0.0001). Morbidity was modeled using robust regression analysis and both body weight (P < 0.0001) and inbreeding (P = 0.013) were significant (r² = 0.77). Smaller less inbred breeds were healthier than larger more inbred breeds.

Conclusions: In this study, body size and inbreeding along with deleterious morphologies contributed to increases in necessary health care in dogs.

Keywords: Canine; Genetic; Inherited; Morbidity; Mortality.