By Carol Beuchat PhD
The United Kingdom Kennel Club has just published a substantial study that documents the recent history of the purebred (pedigree) dogs in its registry (Ilska et al. 2015). It is based on 11,159,418 pedigree records for 222 breeds in its digital archives between 1990 and 2021.
The previous analysis of the registered populations in the UK Kennel Club database is from a decade ago (Lewis et al 2015), so this study is a timely update. They use the same data (with the data in the Lewis study including dogs only up to 2015), so these two studies can be taken together to assess many different aspects of the populations of the breeds and how they have changed over time. The earlier study focused more on genetics, including things like inbreeding, popular sires, and estimates of effective population size (Ne). This new study does more with demographics - population size, fraction of dogs that are bred, numbers of imports and their use in breeding, andthe populations of "purpose bred" dogs (field, conformation, and other activities). The summarized data for all of the analyses are provided in Supplemental Tables.
The previous analysis of the registered populations in the UK Kennel Club database is from a decade ago (Lewis et al 2015), so this study is a timely update. They use the same data (with the data in the Lewis study including dogs only up to 2015), so these two studies can be taken together to assess many different aspects of the populations of the breeds and how they have changed over time. The earlier study focused more on genetics, including things like inbreeding, popular sires, and estimates of effective population size (Ne). This new study does more with demographics - population size, fraction of dogs that are bred, numbers of imports and their use in breeding, andthe populations of "purpose bred" dogs (field, conformation, and other activities). The summarized data for all of the analyses are provided in Supplemental Tables.
The results of this study should be no surprise for those that have been following the fancy for the last decade. Only a small fraction of the purebred dogs produced are bred, and the resulting loss of genetic diversity is a persistent force driving up inbreeding coefficients. The size of the pedigreed dog population is declining in the UK, for reasons that are not clear, but importation of dogs and their popularity for breeding is beneficial both to support population sizes and mitigate loss of genetic diversity.
While much information is summarized in the Results and you should review that material yourself, I'm always interested gaining a broader vew of things, and especially to see how breeds compare to each other. Which breed uses the most dogs for breeding? Which breeds are currently increasing in size, and which have declining numbers? Which breeds should be careful about overly-popular sires?
These types of questions are cumbersome to answer using tables of data. After much fussing and fiddling with the information in the various supplemental tables, I finally decided to create graphs of the data that would make breed comparisons easy. It was a bit of a task, but I found the graphs to be very useful so I have provided them on the ICB website where they are accessible to everyone (see he link below). A graph with 220 breeds will have labels too small to read, so for each of the charts I have also provided a large copy you can open that should be easily readable. I didn't do plots of everything but focused on the ones that were of most immediate interest to me. I might add a few more at my leisure if it looks like people are benefitting from the ones already done.
These types of questions are cumbersome to answer using tables of data. After much fussing and fiddling with the information in the various supplemental tables, I finally decided to create graphs of the data that would make breed comparisons easy. It was a bit of a task, but I found the graphs to be very useful so I have provided them on the ICB website where they are accessible to everyone (see he link below). A graph with 220 breeds will have labels too small to read, so for each of the charts I have also provided a large copy you can open that should be easily readable. I didn't do plots of everything but focused on the ones that were of most immediate interest to me. I might add a few more at my leisure if it looks like people are benefitting from the ones already done.
ACCESS THE PAPER, SUPPLEMENTAL TABLES, AND MY GRAPHS
You can access the graphs I created, as well as download a copy of the paper and a zip file of the supplemental tables from the ICB website under the "Projects" tab ("Ilska et al 2025 Figures"). (https://www.instituteofcaninebiology.org/ilska_figures-551693.html)
I was swimming in chart chaos putting these together, so if you spot any errors, please let me know. I hope these are useful to you.
You can access the graphs I created, as well as download a copy of the paper and a zip file of the supplemental tables from the ICB website under the "Projects" tab ("Ilska et al 2025 Figures"). (https://www.instituteofcaninebiology.org/ilska_figures-551693.html)
I was swimming in chart chaos putting these together, so if you spot any errors, please let me know. I hope these are useful to you.
REFERENCES
Ilska, J.J., Ryan, P.B. & Tolhurst, D.J. Modern pedigree dogs in the United Kingdom Kennel Club: a journey through shifting population landscapes and demography.Companion Anim. Health Genet. 12, 3 (2025). https://doi.org/10.1186/s40575-025-00142-1.(pdf)
(https://cgejournal.biomedcentral.com/articles/10.1186/s40575-025-00142-1#citeas)
Lewis et al., 2015. Trends in genetic diversity for all Kennel Club registered pedigree dogs breeds. Canine Genetics and Epidemiology 2:13. DOI 10.1186/s40575-015-0027-4
(https://cgejournal.biomedcentral.com/articles/10.1186/s40575-015-0027-4)
Ilska, J.J., Ryan, P.B. & Tolhurst, D.J. Modern pedigree dogs in the United Kingdom Kennel Club: a journey through shifting population landscapes and demography.Companion Anim. Health Genet. 12, 3 (2025). https://doi.org/10.1186/s40575-025-00142-1.(pdf)
(https://cgejournal.biomedcentral.com/articles/10.1186/s40575-025-00142-1#citeas)
Lewis et al., 2015. Trends in genetic diversity for all Kennel Club registered pedigree dogs breeds. Canine Genetics and Epidemiology 2:13. DOI 10.1186/s40575-015-0027-4
(https://cgejournal.biomedcentral.com/articles/10.1186/s40575-015-0027-4)
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Visit our Facebook Groups
ICB Institute of Canine Biology
...the latest canine news and research
ICB Breeding for the Future
...resouces for breeders
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