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The ISSA Outcrossing Plan - Reasons to Outcross and Existing Breed Management Programs

Our next step was to utilize all of the information we had gathered to examine our reasons for outcrossing and determine if they were still compelling. We also defined the ways that our breed was already attempting to solve or work with our known limitations and issues.

Below you'll another excerpt from the actual report we contructed for our first outcrossing project.

Outcross Planning Checklist

International Shiloh Shepherd Alliance

April 2017

PART ONE, SECTION THREE: DEFINE REASONS TO OUTCROSS AND CURRENT NON-OUTCROSS EFFORTS MADE TO IMPROVE THE BREED’S CIRCUMSTANCES

❖ Define specific reasons why an outcross is necessary / desirable.

The Shiloh Shepherd as developed by Tina Barber in the ISSR and carried through into the ISSA comes down from only 20 founders. In addition, all those founders are related to some extent, as all descend from German Shepherd dogs, even if taken from isolated populations with (sometimes) an additional breed mixed in. Added to that, several of these founders are behind dogs which had only one descendant pass on, sometimes for more than one generation, making the likelihood of retaining any genetic diversity they possessed quite slim.

From pedigree study, we know that the percentage of flock guardian (Sarplaninac or similar) in the current representatives of our breed is barely 2-3% by pedigree, all coming from one dog who is being linebred on continuously as she was a popular founder. We have an additional founder who was around 40% Malamute, also appearing multiple times behind all Shilohs now. This makes the % of Malamute genes by pedigree only 2-4% in the average ISSA Shiloh.

The Czechoslovaky Vlcak outcross has been utilized by very few of our breeders, and where it appears now, it is most often in the third or fourth generation, making its contribution by pedigree % quite low. In addition, the genetic diversity added to the Vlcak breed by the wolves added during the breed’s creation may have been largely overwhelmed by linebreeding back to German shepherds in the following generations. We hope to understand how much diversity the Vlcak line really added when we get the results from our genetic diversity testing with UC-Davis.

In summary, the vast majority of our Shiloh Shepherd genetic diversity comes from the German Shepherd dog gene pool, with its own bottlenecks and relatively low number of founders. Recently, Carol Beuchat of the Institute of Canine Biology posted an estimate of COI for several breeds which used SNP DNA analysis to see how much diversity the breeds actually still possessed. The study found that the average COI of the German shepherd dog gene pool was equivalent to a very high 35% when diversity was factored by DNA instead of pedigree. What this likely means is that any diversity that the Shiloh might have gained from the past outcrossing to GSD’s or their derived breeds is, at best, quite small.

In conclusion, we are a breed with rising COI (coefficient of inbreeding) numbers, based over 90% on another “purebred” with a lack of genetic diversity itself, and a breeding gene pool of less than 150 dogs, all of which are quite related to each other because of the small number of dogs used to create our breed. This, and the rising incidence of genetic disease including reproductive and immune system weakness, are the reason we feel that an outcrossing program to several different breeds in the coming decade is necessary to restore diversity and keep our breed from destroying itself.

❖ State any efforts already being undertaken by the breed club to overcome the problems (other than outcrossing).

Temperament:

All litters are temperament-tested at eight weeks and an effort is made to encourage the most confident temperaments to move forward. Temperament is also assessed at around one to two years of age to see how the dogs have developed. Every breeding dog must have passed a Canine Good Citizen with additional gun-sureness test, or the ISSA customized temperament testing, or have submitted a temperament video to the Breed Wardens for assessment and must pass, before being granted breeding rights.

Health:

We have implemented the following programs:

- Genetic Diversity testing with UC-Davis: We have finalized our initial round of analysis and gotten our preliminary results. This study is enabling us to act to preserve the diversity we currently have, and it should be an excellent tool to guide us in retaining the diversity that we acquire through outcrossing.

- COI calculation: In order to breed less-related dogs, a 30-generation COI report is run on every potential litter. We strive to stay as low as we can, seeking to approve litters under 17.5% COI.

- Health Tracking Database: Our health tracking database utilizes the results of the 2001 Shiloh Shepherd Breed-Wide Health Survey as its baseline, and we have attempted to note every reported genetic health issue since then. We combine this analysis with our COI numbers in considering whether a given breeding should be done (essentially, we create an EBV—-Estimated Breeding Value—-report for each litter proposed). We track issues as they appear, apply the risks to related dogs, and calculate the probabilities of each litter producing an affected pup. The database covers over 20 different disorders reported within the last 15 years. In ISSA, all breeders report incidences of diseases coming from their litters to the Breed Wardens who track this information, so that the risk calculation can be as accurate as possible. We also recently completed a Health Survey of litters born within the last five years.

- Holter Program for GSDIVA Detection: All potential breeding pups must wear a Holter (EKG) for 24-48 hours. It is strongly encouraged to get this done between the ages of five and eight months. It is also strongly encouraged to Holter as many of the pets from each litter as possible, to help determine where the disease lurks and to hopefully gain information pertaining to mode of inheritance (currently unknown). A clear Holter is a necessity for breeding dogs.

- We currently do mandate the following additional health testing for potential breeding dogs: passing hip and elbow x-rays; heart auscultation with follow-up echocardiogram if anything abnormal is heard; and DNA testing for degenerative myelopathy. In the case of the x-rays we also attempt to get this information on as many pet litter mates as possible.

Conformation:

Unfortunately, we are at the point where it is almost impossible to correct the issues with cow hocks or the receding lower jaw on any large-scale basis. We simply do not have enough dogs who are correct (and certainly everyone can’t breed to those dogs who exist). Otherwise, pups are assessed at eight weeks for conformation and reviewed again when they apply for their breeding certificate, and an effort is made to improve on the issues we most often see.


ADDENDUM, POST UC-DAVIS STUDY AUGUST 2017:

Once again, the study has added additional information and clarity to the above. It has verified that, though the Czechoslovaky Vlcak outcross did appear to add an amount of diversity, specifically in the DLA haplotypes (based on analysis of our remaining F2 dog from that outcross), it was not nearly as much overall as we might have expected. Also, being based on an F2 rather than an F1 outcross dog, we cannot be sure that one of the haplotypes didn't come from the other side of the pedigree, which also is linked to (different) outcross blood.

Likewise, we are finding that dogs from unique or double F3 (two past outcrosses in the third generation) lines are often not any more diverse than dogs which are four or more generations removed from past outcross blood. In fact, some of our rare haplotypes and alleles are possessed by dogs with relatively high COI.

Given all of this information, we will be very interested to track the different alleles and haplotypes we hope to gain from our upcoming crossbreeding, to see if the F2 and F3 generations show markedly more diversity on average than that gained from past GSD-related outcrosses.


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© 2016 International Shiloh Shepherd Alliance, Inc.