1. Miniature Bull Terriers: Breeding Strategies for Health Dr Sarah Blott Animal Health Trust The science behind animal welfare

2. TOOLS to aid breeding decisions Single gene diseases DNA tests Complex diseases Estimated Breeding Values (EBVs) Genomic BVs (based on DNA) Mate selection program BREEDING PROGRAMMES for long-term health General health Management of genetic diversity Optimised breeding programmes Reduce or eradicate known disease and maintain long-term health

3. Overview Gene pool and genetic diversity Inbreeding Approaches to minimising diversity loss Current situation in the MBT Future breeding strategies

4. Gene pool and genetic diversity

6. Inbreeding Inbreeding coefficient Coancestry/kinship

7. Inbreeding coefficient 1/2 (1/2) 6 = 0.0156

8. Genetic bottlenecks

9. Diversity loss High risk factor for emergence of new inherited disease Long-term health means managing the loss of diversity Controlling the rate of increase of inbreeding

10. Control of inbreeding What is the end goal? Constrain rate of inbreeding (ΔF) to no more than 0.5% per generation Effective population size (N e )= 100 At least! If below this, fitness of the population will steadily decrease and population will become unviable in the long-term

11. Possible approaches Minimising coancestry (kinship) of matings Increasing numbers of animals used for breeding Equalising the use of males and females Optimising genetic contributions Inter-breeding

12. Miniature Bull Terrier

13. Number of KC registrations 4,110 dogs354 sires797 dams

14. Number of sires and dams used Mean no. sires = 18.7 Mean no. dams = 33.2 Ratio = 1.72 dams/sire

15. Ratio of dams/sires 1981 1993

16. Percentage dogs used for breeding 15% males become sires 40% females become dams

17. Observed and expected inbreeding

18. Effective population size (N e ) % per generationN e Registered/year MBT1.148203 IRWS1.828133 CKCS0.412311,903 Labrador0.510326,757

19. Number of offspring per sire/dam Sires Mean no. offspring = 13.7 Dams Mean no. offspring = 5.6 4 sires > 100 offspring 15 dams > 20 offspring

20. Population relationships MBT born between 2006-2008

21. Conclusions scope for improvement minimising coancestry (kinship) of matings optimum contributions (no. of offspring)

22. PLL approx. 1200 dogs of breeding age in UK genotype all possible dogs and re-select breeding individuals? breed with carriers for one further generation and select unaffected homozygote (normal) replacements further analysis based on pedigree and genotyping results

23. Inbreeding coefficientKinship coefficients Rosedawn Delilah0.04 Ballymore Delight0.02 Ballymore Samson0.01 Legend of Kilkenny0.02 Rosedawn Diamond0.12 Lordswood Romancer0.08 Recommended http://www.the-kennel-club.org.uk/services/public/health/search/Default.aspx

24. Acknowledgements Dr Tom Lewis (KCGC at the AHT) Dr Jeff Sampson (The Kennel Club)