The biggest challenge facing purebred dog breeders now and in the future is the management of genetic disorders. Over the last few decades, inbreeding and loss of genetic diversity have resulted in an increase in the expression of recessive alleles as well as inbreeding depression, which affects things like fertility, puppy mortality, and lifespan. Producing healthy dogs in the future will require management of a breed's most precious resource, its gene pool, so that breeders have options for controlling inbreeding and minimizing loss of genetic diversity.

The problems of inbreeding and loss of genetic diversity are common to any closed population of animals, whether wild or captive,. (Purebred dog breeds are considered to be "closed" populations because a closed studbook prevents introduction of new animals.). Tools have been developed that can explore the consequences of particular breeding strategies to the genetic status of the population for many generations in the future. These allow breeders and population managers to make decisions that can be based on data instead of untested assumptions and "gut" feelings. Software for genetic management  is used to design breeding programs for endangered species as well as domestic animals, and it can be used to develop genetic management strategies for dog breeds as well.

A program specifically designed for purebred dog populations has been used to explore various strategies for controlling the rate of inbreeding in Golden Retrievers in The Netherlands (Fig. 1; Windig & Oldenbroek 2015). The designers tested a variety of strategies, including restrictions on the use of popular sires similar to those that have been implemented in some European countries. They could vary the population size and the number of breeding animals of both sexes, the timing and number of litters produced by popular sires, the selection of breeding animals based on their relatedness to the rest of the population, the age structure of breeding animals, and other parameters.

The simulation also showed that, while restricting the number of litters sired per year by popular sires could reduce the rate of inbreeding, lifetime restrictions on the number of litters had less of an effect on inbreeding, and in some cases it could paradoxically be less effective. This was because sires were removed from the population sooner and replaced with new males, which shortened the generation interval. Of all the variations in breeding strategies, the most effective at reducing the rate of inbreeding over the long term in this particular simulated population was to restrict breeding to the animals with the lowest average genetic relatedness to the other animals in the population

Because the simulated population was based on the actual population of Dutch Golden Retrievers, those breeders were able to evaluate the effectiveness of a variety of possible strategies and select one that was most practical for their breed. Simulations like this can be done for any breed or population of animals, and they can take much of the guesswork out of designing strategies that will meet the goals of breeders and also manage inbreeding of the population as a whole. There are a number of programs available now that are useful for population genetic modeling, and whichone is most useful will depend on the features of the specific population of animals and the goals of the breeders. Information from DNA testing and genotyping can also be incorporated into a simulation, so for example a strategy can be designed to reduce the frequency of a recessive mutation without damage to the gene pool.

A variety of tools developed for genetic management of populations are now available through ICB and can help breeders improve and protect the health of their gene pool. Although they have not been routinely used for dog breeding in the past, they could make it much easier for breeders to lessen the burden of genetic disorders and manage inbreeding and loss of genetic diversity. Genetic management of their breed should be a core commitment of responsible breeders, and now we have tools that make this possible.

Windig JJ & K Oldenbroek. 2015. Genetic management of Dutch Golden Retriever dogs with a simulation tool. J Anim Breeding and Genetics 2015: 1-13. doi:10.1111/jbg.12149

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