Managing Inbreeding

Breed Conservation for the English Shepherd

By Carolyn Christman and Rebecca Wingler

This is an update and expansion an essay written September 21, 2003 by Carolyn Christman.

Part Four.   How to Manage Inbreeding

Ann Cassidy 2013_kitchi_bibi_twende_

Submitted by Ann Cassidy

Domestic animal breeds have been created through selective breeding. Each generation was selected for a certain combination of traits and for basically the same job. When this works, breeders’ efforts are able to balance uniformity and predictability and create healthy, sound animals that have enough genetic diversity in the population to adapt to changing conditions.

All purebred dogs and other animals with closed studbooks descend from a set of common ancestors known as founders.  Founders establish the base of diversity. In some breeds, there are successive waves of founders that join the breed and become a part of its base of genetic diversity. Diversity is then able to be maintained or reduced by natural selection and by breeder selection, along with environmental events that may create a bottleneck.

English Shepherd history has a few more twists and turns than do some other breeds. It has a long history in a big place (North America), unlike many other landraces that evolved in a small geographic area. Though well known, the ES was not very well documented as the recorded history was divided among a variety of clubs and registries.

The ESCR, supported by the research and efforts of many breeders and owners, is pulling together the breed’s full history one pedigree at a time to build the database. This tool will give us a much greater opportunity to see the breed’s development more clearly. For example, it now appears that there was a genetic bottleneck during the late 1990s and some of the genetic diversity of the breed was most likely lost during that time. This would have been at the same time that the small-scale diversified farming began to decline. Perhaps the loss of this niche contributed to the genetic bottleneck.

Another twist, and not unexpected, is that the ES breed has had some introduction of outside stocks, as is the case of other domestic breeds.   In the case of the ES, these introductions were peripheral to the main breed population and do not seem to have a long-term impact.

For example, one instance of outside introductions to the ES breed occurred in Tom Stodghill’s breeding program and was reported in his magazine Stodghill’s Animal Research Magazine. One of his breed types – the Advanced English Shepherd – was produced through crossing the ES with Beauceron. One of the sires used was Acuman, an Advanced English Shepherd who was from the old Bozo line, plus new blood, mentioned in issue #44. In issue #46, Stodghill stated the Advanced English Shepherd carried 12 ½ to 25% of the Beauceron blood. In future issues of ARF, talk about the Advanced English Shepherd disappeared. There were just a handful of ES breeders who owned an Advanced English Shepherd for use within their breeding program, so these dogs became a part of the ES history.

Another example is the presence of Border Collie ancestry within the pedigree of Shininger’s Brandy. Fred Shininger purchased Brandy from Dalton Sommers, after seeing Brandy’s dam working livestock at the Sommer farm. It wasn’t until years later that it was discovered that one of Brandy’s grandparents was an imported and registered Border Collie from New Zealand.   Brandy was registered through IESR as an English Shepherd.

Breeding as a Balancing Act

Barbara Brown 2014 Gyp & Sandra Dee

Submitted by Barbara Brown

The stewardship of every breed requires a group effort to maintain predictability and diversity. One of the challenges breeders worry about is the management of inbreeding so that it does not damage their herds or their breeds. How can English Shepherd breeders successfully manage the inevitable challenges that may be created with inbreeding? In other words, will our breed still be around and healthy in the future? An overarching concern is what kind of conservation strategies to use and what kinds of role models exist for us in the dog breed world.

Inbreeding may occur at the level of the individual breeder’s animals or at the entire breed level. Inbreeding at the herd level is a relatively low threat to the entire breed as long as breeders are willing to share and bring in stocks that are genetically different enough to be a meaningful outcross.

Inbreeding that occurs across the entire breed is much more of a problem. One comfort or caution is that individual breeds vary in the tolerance for inbreeding based on their own genetic history, so this may be more or less of a problem depending on the breed’s circumstances and its historic selection and breadth.

Another worry is how to recognize that inbreeding is occurring. It can be measured by the Coefficient of Inbreeding, or COI. The COI is a quantitative measure of the number of common ancestors in one or more pedigrees. The higher the number means the more ancestors in common; the lower the number means fewer ancestors in common. For example, a zero COI comes from two completely unrelated parents, while a 25% COI results from the mating of full siblings. There is a complex formula used to make the calculation, but basically it is measure of the relatedness of two individuals.

To be truly useful, the COI must be given in its historical context.   How many generations does it include? How do these generations fit the breed’s history? Are all of the founders known, or are there other waves of founders that have contributed to the breed? The COI should always be defined by the number of generations used to arrive at the number.  This last statement is very important to understanding COIs and its usage when evaluating a pedigree. For example, dogs showing a COI of zero at three generations most likely will show a higher COI the more generations that can be added to the pedigree, because there is a greater likelihood of duplicate ancestors appearing in the pedigree.

A keen eye can also see beyond the COI to the diversity and uniformity in a pedigree by knowing the lines and families across the breed as well as the relationship between these. It is important to know which lines are out of fashion and under-represented as well as those which are the most popular. This is another way to evaluate the breed’s status and figure out how to manage inbreeding.

Signs of inbreeding

Signs of inbreeding may be seen through observation. The assumption is that inbreeding increases the expression of deleterious recessive genes which may give rise to health problems. The deleterious recessive genes are always there, but they become more obvious through close inbreeding when animals receive two copies of recessive genes which are otherwise hidden.   Yet the other impact may be a subtle but real loss of breed qualities, especially those related to survival and reproduction, such as longevity and soundness.

Inbreeding may occur at the herd / flock / pack level. In livestock, where animals are kept in larger herds and flocks, and where they are bred regularly, the presence of inbreeding is more obvious. Its signs may be seen in changes generation to generation – for example, reduced fertility and reproductive fitness, shorter lifespans (especially working lifespans), and less ability to do the job as well. Inbreeding at this level is not a huge concern since the remedy lies in other parts of the breed. For example, if a livestock breeder encounters these problems, the remedy can be made by introducing a male or female from other bloodlines in the breed. For dog breeders, the signs may be more subtle. It is especially challenging for breeders given that pups will be sold over a large geographical area without the chance to see them mature to see if problems are perhaps on the horizon.

Inbreeding that occurs at the breed level is a concern for its possible impact on breed health and conservation. The likely cause is the overuse of the same sires and bloodlines and the same selection criteria. It occurs when everyone is trying for the same look or the same market. It also occurs, ironically, when everyone strives to avoid inbreeding by seeking to breed the most distantly related animals to one another. The result is casting aside out-of-fashion animals and bloodlines, which then may be lost. If this occurs, the breed may become inbred all in the same direction.

In these cases, each and every generation will have less genetic distance than the one that came before: the breed becomes slowly inbred all in the same direction, leaving no outcrosses available within the breed.

There are two overall approaches for the challenge of inbreeding and small population size. One is to introduce animals from another breed. On the mild end of this general approach would be something like a “grading up” program in livestock. Grading up has the basic goal of creating more females for the breed, and ideally females that are somewhat less related to one another. Grading up uses females of a closely related breed, which are then bred to purebred sires of the rare breed. The female offspring are then bred to different purebred sires. After two generations of breeding, the offspring are 75% purebred and their own offspring are registerable as pure stock. This was done historically with the Dutch Belted dairy cattle breed (used Holstein cows) and the Suffolk Punch draft horse (used Belgian mares) to save these breeds from extinction.

On the dramatic end of the spectrum is to throw open the studbook to animals of another breed with the goal of bringing in outside genetics – usually done not in response to a genetic need but more for a financial need, to make the breed more marketable and fashionable. An example is the transformation of the European warmblood breeds, previously multi-purpose driving and hunting horses, into “sport horses” for the show ring through the widespread introduction of Thoroughbred blood. Another would be the introduction of Saddlebreds into the Morgan horse breed to create a show type. This crossbreeding does create genetic dilution and, if done on a broad scale, ultimately the loss of the breed’s unique genetic character.

Purposefully Managing Inbreeding through Linebreeding within the Breed

Blankenship's Duke of Winsor

Blankenship’s Duke of Winsor

A different strategy drawn from livestock conservation is to purposefully manage inbreeding before it is a problem. The goal is to work at the breed level to maintain all of the diversity that is currently present in the breed and thus to never need an emergency genetic transfusion from outside.

Phil Sponenberg of The Livestock Conservancy has written about the use of linebreeding as a way to manage inbreeding in rare livestock breeds. It comes from his observation of how some landraces survived despite very low population sizes. For example, early this century, the Texas Longhorn breed was found in only nine small family herds in Texas. These herds were geographically isolated and, though inbred, were distinct from one another. [It also helped that these cattle were very long-lived and the older females were quite capable of calving into their late teens.]

We can use the idea of the Texas Longhorn lines to see the pattern of linebreeding to manage inbreeding. Draw a circle that represents the whole breed, and then draw some small circles inside it, with some of the circles overlapping a little and some not. The smaller inner circles represent the historic lines of within the breed. They act as spacers, keeping the circle from collapsing. Another view is that they are spokes which hold the wheel in shape. Most of the animals in the circle, in the breed, will be line-crossed individuals but a few, in the circles or spokes, are line-bred.

The historic lines (the circles / spokes) are distinct genetic sub-categories within the breed. Each of these is being linebred on purpose and in a different direction, each with slightly different and complementary priorities. Thus, the potential inbreeding problem for the entire breed is managed through the judicious use of linebreeding in smaller groups going in different directions. If and when any of the historic lines need an outcross, a male or female can be brought in from another line – because there is always an outcross available within the breed.   [Bringing in a male from another line will have a significant impact, while bringing in a female and then using her male offspring as a sire creates a more modest impact.]

The value of historic lines to the breed was first articulated in 1996 for horse breeders at a meeting called “Preserving Your Part of the Global Herd” hosted by The Livestock Conservancy and the Kentucky Horse Park in Lexington, Kentucky. Part of the discussion focused on the conservation of horse breeds such as the Morgan which had multiple and distinct historic lines as well as large populations of line-crossed horses and show-ring selected animals. It was at this discussion that the concept of the lines as spokes of the wheel was first considered and seemed to make sense.

Why the idea of spokes? The Tao Te Ching, one of the classics of the Asian religion Taoism, says it this way: “we join spokes together in a wheel, but it is the inner space that makes the wagon move.” Holding space within the breed is another way to imagine conserving genetic distance and diversity.

The Challenge of Linebreeding

closeup+of+1951+UKC+ES

Early Stodghill Black & Tan

Linebreeding is not for everyone. It requires breeder skill and attention. Breeders have to be alert for any signs of loss of vigor, loss of reproductive fitness, or unsoundness. Then they must be willing to cull their breeding stock via neutering and to bring in an outcross from another line or a linecross. They have to know the strengths and weaknesses of their lines, and they know where their line fits into the history and current status of the breed.

For these reasons, only a few breeders in a breed will take on this responsibility. As is true now, most breeders will be producing line-cross animals – which often have nice bloom and presence from the hybrid vigor of the cross. Linecross animals will always predominate in the breed. Linebred animals will always be a smaller percentage of the breed. Yet these groups of distinct, well managed stocks may be the key to the ES’s long term health. The retention of more sires, including out-of-fashion sires, is an important contribution to the breed’s future.

There are many fine historical ES breeders, most of whom judiciously crossed a variety of lines to produce pups.  A few of the breeders used linebreeding as a primary strategy, and therefore their dogs may more correctly be considered historical lines because they are relatively distinct from the majority of the population    This is a start to the discussion.  Keep in mind that many pedigree records remain inaccessible at other organizations.  There may be others, though we think these are a starting point to the discussion of historic lines.

  • Harold Mohns and his wife in WI bred black and white ES. There were four generations of the Elmer (Harold Mohns great grandfather) and Mohns family ES. Their work covered a time period from around 1880 through the late 1980’s. Mohns rarely acquired dogs from other breeders.
  • Sheryl Chesney and her family in South Carolina raised ES for over 100 years.
  • Tom Stodghill is best known for his black and tan ES, developed and maintained through a “clockwise” breeding program in Texas. He was breeding ES from the mid 1940’s until his death in 1989.
  • John and Polly Blankenship in TN were also known for their black and tan ES. They were a part of the shift from ARF to IESR. Their breeding program started around the early 1950’s. People today still inquire about the Blankenship line.
  • Guy Wilson in GA began with two females (one from his mom and one from an aunt) and bought Wilson’s Ozark Tim. He raised ES from the late 1960’s/early 1970’s, through the early 1980’s. He retired due to health issues. His kennel was given to his neighbor Theron Ward, who continued the Guy Wilson linebreeding. This is still a very vital and prospering line, especially well represented in the UKC registry.
  • De Butcher in Oklahoma based her line on her foundation male Augie, who was registered through IESR. Augie was purchased from Dorothy Anderson and born in 1982. The Butcher line is alive and well today.
  • Sagan

    Jarratt’s Sagan

    Ed Lynn Jarratt in North Carolina grew up with unregistered ES. He bought his first registered dog Kip around 1964 and only bred when needing the next generation, plus kept most of his pups. His line was based off of Sagan, the son of Kip. He owned ES from the mid 1960’s until his death in 2008.

  • Connie McCain in TN developed a line of clear sable and white ES with black noses. Mrs. McCain and her neighbor, Mr. Baker were known for their Three Oaks Kennel dogs. Ralph Morris in MS continued this line from the 1980’s through the 1990’s, by adding Anderson dogs to the mix, therefore creating a larger, clear sable and white ES with black noses
  • Sandra Ransom in GA was breeding during the 1970’s and possibly the 1980’s. She was known for having some unusual colors in her breeding program.
  • The Piper line was bred in VA and is being continued by Joe and Genevives Piper. The line was started in 1963 and was selected for a smaller height.

For historic lines to be conserved, today’s breeders must recognize the need for them to be protected and maintained as distinctive populations and not used up in line-crossing.

Using historic lines in a mixture does not preserve them; some of each line must be kept in pure form. Even if breeders are primarily focused on line-crossed individuals, the parent foundation lines must be preserved by someone as they are. A few new breeders are needed to get interested in their survival.

This goes back to the concept of a philosophy of breeding and of conservation by the community. Ask: What is my distinctive contribution to the English Shepherd? Who is breeding the outcross I will need in five years or ten years?   Keep an eye on the breed as a whole and its well-being. Have confidence in the English Shepherd breed and continue to work for its future and to create a sound and healthy legacy.

References

Phillip Sponenberg and Carolyn Christman. 1995. A Conservation Breeding Handbook. Pittsboro, NC: The Livestock Conservancy.   (This is the precursor book to the other references.)

Phillip Sponenberg and Donald E. Bixby, 2007. Managing Breeds for a Secure Future. Pittsboro, NC: The Livestock Conservancy. 919-542-5704. http://www.livestockconservancy.org/

D. Phillip Sponenberg, Jeanette Bergenger, and Allison Martin, 2014. An Introduction to Heritage Breeds. Pittsboro, NC: The Livestock Conservancy. http://www.livestockconservancy.org/