Science Round-Up

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196 – March, 2022

By Caroline Coile

The Effect of Inbreeding, Body Size and Morphology on Health in Dog Breeds

Dannika Bannasch’s lab at UC Davis is one of the most active canine genetic research labs in the world. In this study they examined the relationships between inbreeding, morphology and health using genotype-based inbreeding estimates, body weight and insurance data for morbidity. They examined genetic data from 49,378 dogs representing 227 breeds, obtained through commercial DNA testing. Some breeds were represented by as few as 30 individuals, others with as many as 4728; the average number per breed was 217. They determined the coefficient of inbreeding (COI) in 19 breeds using the genotypes of 8 to 20 individuals within each of these breeds.

The average COI was 0.25, equivalent to the progeny of a parent X offspring or sibling X sibling breeding. Only 12 breeds had COIs less than 0.10 (for comparison, the progeny of two first cousins breeding would have a COI of 0.06). These were mostly landrace breeds (such as Danish-Swedish Farm Dog, Mudi and Koolie) or breeds with recent cross-breeding (such as the Tamaskan Dog, Barbet and Australian Labradoodle).

To investigate the effect of inbreeding on health, morbidity (disease) records were obtained from Agria pet insurance for 162 of the breeds. The mean morbidity across all breeds was 1574 per 10,000 DYAR (Dog Year at Risk) for purebreds and 1265 per 10,000 DYAR for mix breeds (Note: a lower number is better). Morbidity values for 11 breeds with a mean COI less than 0.12 was 1282; for 66 breeds with a COI between 0.12 and 0.25 the morbidity was 1537; and for 85 breeds with COI over 0.25 the morbidity was 1626. In other words, morbidity rose as inbreeding rose.

In general, the higher the inbreeding the higher the morbidity, but there were some exceptions. The Border Terrier, Basenji, Collie, and English Setter breeds have high inbreeding but low morbidity. Likewise, the Malinois, Pomeranian and Russian Toy have lower inbreeding and high morbidity.

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196 – March, 2022

Short URL: https://caninechronicle.com/?p=225479

Posted by AnthonyA on Mar 19 2022. Filed under Current Articles, Featured. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.