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Breeding, Health & Genetics

Small Population Breeds and Issues of Genetic Diversity

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bell-jerold-1520260577 By Jerold s Bell DVM, Clinical Associate Professor of Genetics, Tufts Cummings School of Veterinary Medicine.  Reprinted by permission of the author.

(This article was originally published in the March 2007 AKC Perspectives Delegates Newsletter.)

Issues of genetic diversity are a concern to dog breeders, and this can be especially so for breeds with small populations. The concern is whether there is enough genetic variation within a breed’s gene pool to maintain health and vitality. Breeders should be concerned about genetic diversity, because there are examples where damage has been done to a breed due to breeding practices. Restriction of genetic diversity can also occur in large population breeds.

All genes come in pairs: one from the sire and one from the dam. Each gene in the pair is called an allele. If both alleles in a pair are of the same type, the gene pair is homozygous. If the two alleles are different, the gene pair is heterozygous. While each dog can have a maximum of two different alleles at a gene pair, many different alleles are potentially available to be part of the gene pair. The greater the number of alleles that are available at each gene pair (called genetic polymorphism), the greater the genetic diversity of the breed.

If there is no breed diversity in a gene pair, but the particular homozygous gene that is present is not detrimental, there is no negative effect on breed health. The characteristics that make a breed reproduce true to its standard are, in fact, based on non-variable (that is, homozygous) gene pairs.

The origins of the breeds have a lot to do with genetic diversity. A breed established with a working phenotype tends to have diverse founder origins, and significant diversity. Even with substantial population bottlenecks, the breed can maintain considerable amounts of genetic diversity. This was shown in a molecular genetic study of the Chinook breed, which was reduced to 11 modern founders in 1981. Breeds established by inbreeding on a limited number of related founder individuals could have a reduced diversity. Many breeds have also gone through diversity reducing bottlenecks; such as occurred during World War II. For most of these breeds, their gene pools have expanded through breeding for many generations, resulting in a stable population of healthy dogs.

There are two factors that must be considered when evaluating genetic diversity and health issues in a breed; the average level of inbreeding, and detrimental recessive genes. With a small population, there is a tendency to find higher average inbreeding coefficients due to the relatedness between dogs from common ancestors. There is, however, no specific level or percentage of inbreeding that causes impaired health or vigor. The problems that inbreeding depression cause in purebred populations stem from the effects of deleterious recessive genes. If the founding population of a breed produces a high frequency of a deleterious recessive gene, then the breed will have issues with that disorder. This can be seen as smaller litter size, increased neonatal death, high frequency genetic disease, or impaired immunity. If these issues are present then the breed needs to seriously consider limited genetic diversity.

The issue of high average inbreeding coefficients is one that all breeds go through during their foundation. As the population increases and the average relatedness of dogs goes down (based on a fixed number of generations), the average inbreeding coefficient for the breed will go down. The effect of initially higher inbreeding coefficients in small population breeds will depend on the presence of deleterious recessive genes that will be expressed when homozygous.

Some breeders discourage linebreeding and promote outbreeding in an attempt to protect genetic diversity in their breed. It is not the type of matings utilized (linebreeding or outbreeding) that causes the loss of genes from a breed gene pool. Rather, loss of genes occurs through selection: the use and non-use of offspring. If a breed starts limiting their focus to breeding stock from a limited number of lines, then a loss of genetic diversity will occur.

The process of maintaining healthy lines, with many breeders crossing between lines and breeding back as they see fit, maintains diversity in the gene pool. If some breeders outbreed, and some linebreed to certain dogs that they favor while others linebreed to other dogs that they favor, then breedwide genetic diversity is maintained. It is the varied opinion of breeders as to what constitutes the ideal dog, and their selection of breeeding stock based on their opinions, that maintains breed diversity.

The most important factor for diminished genetic diversity in dog breeds is the popular sire syndrome. The overuse of a popular sire beyond a reasonable contribution through frequent breedings significantly skews the gene pool in this direction, and reduces the diversity of the gene pool. Any genes that he possesses – whether positive or negative – will increase in frequency. Through this founder’s effect, breed related genetic disease can occur. Another insidious effect of the popular sire syndrome is the loss of genetic contribution from quality, unrelated males who are not used for breeding. There is a finite number of quality bitches bred each year. If one male is used in an inordinate amount of matings, there will be fewer females left for these quality males that should be contributing to the gene pool. The popular sire syndrome is a significant factor in both populous breeds and breeds with small populations.

The best methods for ensuring the health and diversity of a breed’s gene pool are to:

  1. Avoid the popular sire syndrome.
  2. Utilize quality dogs from the breadth of your population to expand the gene pool.
  3. Monitor genetic health issues through regular health surveys.
  4. Do genetic testing for breed-related disorders.
  5. Participate in open health registries, such as CHIC (www.caninehealthinfo.org) to manage genetic disorders.

 

(This article can be reprinted with the written permission from the author: jerold.bell@tufts.edu)

Related article – Outcrossing Does Not Equal Gene Pool Diversity

Photograph courtesy of Susan Roy Nelson is not intended to illustrate any point in the article, it is presented for your viewing pleasure only.

 

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Breeding, Health & Genetics

Outcrossing Does Not Equal Gene Pool Diversity

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In previous articles we’ve talked about the shrinking population of the purebred dog and specifically about how much smaller the Gordon Setter population is today – over 70% fewer Gordons than twenty years ago. The current bottleneck in the number of Gordon Setters available for breeding calls for us, as responsible breeders, to evaluate each mating more carefully to determine if it will accomplish our own goals while also considering the impact our mating will have on the breed gene pool. As breeders in today’s world we are not only charged with improving the breed, we are also called upon to ensure that our breeding activity has a positive impact on the preservation of the breed gene pool.  The good news my friends, is that all of this can be less painful to accomplish than you might have thought.

For topics like this I call on experts for advice, and I am grateful to Jerold S. Bell DVM, Clinical Associate Professor of Genetics, Tufts Cummings School of Veterinary Medicine for the guidance he’s offering. Jerry’s article “Small Population Breeds & Issues of Genetic Diversity“ is the resource used for this article and is quoted here, and reprinted entirely elsewhere on the blog with his permission. (Click the title above to link to that article.)

Has the Gordon Setter population reached a level where we should consider it a “small population breed”? Perhaps not, yet..who’s to say? The point here is that the population of the Gordon Setter has shrunk dramatically (Honey, I Shrunk the Kids!) and as it is now substantially smaller, breeders must be aware of how important our breeding choices become when viewed in terms of the health of our breed gene pool. Just as there are fewer Gordon Setters, so too are there far fewer breeders bearing the responsibility for their preservation. With fewer breeders we find that many of the older lines are harder if not impossible to find today.

Jerold S. Bell DVM –  *Issues of genetic diversity are a concern to dog breeders, and this can be especially so for breeds with small populations. The concern is whether there is enough genetic variation within a breed’s gene pool to maintain health and vitality. Breeders should be concerned about genetic diversity, because there are examples where damage has been done to a breed due to breeding practices. Restriction of genetic diversity can also occur in large population breeds.

Putting a lesson in genetics aside for another time, let’s talk today about genetic diversity in our breed gene pool.  Quoting Jerold S. Bell DVM  * There are two factors that must be considered when evaluating genetic diversity and health issues in a breed; the average level of inbreeding, and detrimental recessive genes. With a small population, there is a tendency to find higher average inbreeding coefficients due to the relatedness between dogs from common ancestors. There is, however, no specific level or percentage of inbreeding that causes impaired health or vigor. The problems that inbreeding depression cause in purebred populations stem from the effects of deleterious recessive genes. If the founding population of a breed produces a high frequency of a deleterious recessive gene, then the breed will have issues with that disorder. This can be seen as smaller litter size, increased neonatal death, high frequency genetic disease, or impaired immunity. If these issues are present then the breed needs to seriously consider limited genetic diversity. 

In this statement then, as a group of dedicated breeders, we find a key to issues or symptoms, whose frequency of expression within the breed need monitoring. An increase or spike in these symptoms throughout the breed population, that goes beyond normal expectations, should be a cue that breeders need to seriously consider if we are experiencing limited genetic diversity in our breed gene pool. As a group we must be willing to share our breeding experiences with a wide audience of our peers. Additionally, we must understand that GSCA Health and Genetics committee surveys are also a vital indicator of the breed health, especially as it pertains to breed gene pool diversity.

As we talk about gene pool diversity, we may find some breeders who discourage linebreeding and promote outcrossing (outbreeding) as the way to protect genetic diversity in the breed. While this does sound like an easy, and maybe even an obvious answer, outbreeding would not provide the complete solution.

Jerold S. Bell DVM – *It is not the type of matings utilized (linebreeding or outbreeding) that causes the loss of genes from a breed gene pool. Rather, loss of genes occurs through selection: the use and non-use of offspring. If a breed starts limiting their focus to breeding stock from a limited number of lines, then a loss of genetic diversity will occur.

The process of maintaining healthy lines, with many breeders crossing between lines and breeding back as they see fit, maintains diversity in the gene pool. If some breeders outbreed, and some linebreed to certain dogs that they favor while others linebreed to other dogs that they favor, then breedwide genetic diversity is maintained. It is the varied opinion of breeders as to what constitutes the ideal dog, and their selection of breeeding stock based on their opinions, that maintains breed diversity.

The most important factor for diminished genetic diversity in dog breeds is the popular sire syndrome. The overuse of a popular sire beyond a reasonable contribution through frequent breedings significantly skews the gene pool in this direction, and reduces the diversity of the gene pool. Any genes that he possesses – whether positive or negative – will increase in frequency. Through this founder’s effect, breed related genetic disease can occur. Another insidious effect of the popular sire syndrome is the loss of genetic contribution from quality, unrelated males who are not used for breeding. There is a finite number of quality bitches bred each year. If one male is used in an inordinate amount of matings, there will be fewer females left for these quality males that should be contributing to the gene pool. The popular sire syndrome is a significant factor in both populous breeds and breeds with small populations.

I believe as a whole, that Gordon Setter stud dog owners have worked hard to manage stud dogs properly to avoid the “popular sire syndrome”. This is not an easy task to manage as so many variables, including emotions come into play. Hats off to all who have kept a diligent and watchful eye on our breed through proper stud dog management.

As I look back at what Dr. Bell has written, I realize that our breed is fortunate to have had many breeders, both past and present, who have contributed much to preserve the Gordon Setter; sometimes they contributed matings that improved specific aspects of the breed and sometimes they contributed by using breeding practices that preserved genetic diversity. Moving forward, our breed needs us to continue to attract and mentor a diverse group of breeders who also possess an understanding of the principles of gene pool diversity. As we have seen, there is simply not one step or one action to preserve diversity, instead there is a collection of various actions, that when understood and followed by the individual breeder, with each breeder working alongside the many other breeders – it is when we work as a collective group that we accomplish that one common goal – preservation of the purebred Gordon Setter…oh, and don’t forget there is still improvement of the breed to consider!

Jerold S. Bell DVM writes:  *The best methods for ensuring the health and diversity of a breed’s gene pool are to:

  1. Avoid the popular sire syndrome.
  2. Utilize quality dogs from the breadth of your population to expand the gene pool. (as new genes cannot be added to a closed registry this refers to preserving genes that might otherwise be lost by selection of only a few sires out of the many available)
  3. Monitor genetic health issues through regular health surveys.
  4. Do genetic testing for breed-related disorders.
  5. Participate in open health registries, such as CHIC (www.caninehealthinfo.org) to manage genetic disorders.

*  Small Population Breeds & Issues of Genetic Diversity by Jerold S. Bell DVM

Photograph by Susan Roy Nelson shared for your viewing pleasure, is not intended to illustrate any point in the article.

 

 

 

 

Breed Standard, Breeding, Care, Dog Shows, Field Events, Performance Events, Training, Whelping

NEWS FLASH – Gordon Setter Students & Mentors

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I started a new discussion group that you may find totally useful if you’re seriously into breeding and/or competing with your Gordon Setter. Now, I realize that many of you are not on Facebook and may well have sworn never to go there BUT you don’t have to turn into a Facebook junkie, nor do you need to accumulate a slathering of friends, but you will need to set up a Facebook account in order to view and post to the group.  There are already fabulous discussions starting, questions being posed, and pictures being shared of dogs from way back, all things educational can be shared here.

Here is the link Gordon Setter Students & Mentors click here if you’d care to check it out or join the group.

Gordon Setter Students & Mentors

Description

Welcome Gordon Setter students and mentors! This group is meant to serve as a resource and learning tool for Gordon Setter fanciers who are serious students or experienced breeder/exhibitors willing to join forces where everyone can learn about and mentor the art of breeding better Gordon Setters. A place also to fine tune our skill and expertise when competing in conformation, performance or field events. Topics might include such things as genetics, structure, pedigrees, ancestors, health, and proper care, grooming, as well as training tips pertaining to competition in conformation, performance and field events. To make the most of this forum you are encouraged to submit questions, content and photos to provide examples as well as actively participate in discussions with helpful answers and guiding principles.

Things to keep in mind:

No personal attacks, ridicule, or harassment on or about another member’s post. You will be removed from the group and blocked. We don’t always need to agree and various opinions on a topic are encouraged to promote a learning environment, however remember when you are expressing an opinion to please do so in a tactful and polite manner.

Since this group is meant to serve educational purposes only, please do not submit your win photos and brags, we do love to see those and are very happy for you, but let’s post them on other forums to maintain focus here. The same would be true of those happy Gordon photos we post just for fun.

Please focus on the positive traits of any dog pictured. If you have constructive criticism always be considerate and tactful in your comments to ensure you are providing encouragement as well as an educational experience for the student. Please do share educational articles and links to other sites that will educate and promote better breeding and competition practices.

No SPAM or ads to promote the sale of merchandise or dogs. Spammers will be removed.

No personal attacks on other members! We are here to help each other learn and we will respect everyone and treat each other with dignity because of our differences, a different view could be where a new learning begins.

Enjoy!
Sally Gift, Mesa AZ
Photo by Bob Segal – 2015 GSCA National Specialty
Breeding, Health & Genetics

…and the survey said? Or – what were the results of the breeder surveys?

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You know what? There are Gordon Setter breeders everywhere and I’ve found that you love to find ways to share experience and information with each other! At least, that’s what our surveys told me about you, our readers.  A while back I put a couple of short questionnaires out on Gordon Setter Expert to see what readers were experiencing on the breeding front, you know, to get some idea of what you folks might want to hear about based on your experience.

Photo by Bob Segal
Photo by Bob Segal

The surveys gathered information from 146 matings, and geographically the majority, about 95% were from the United States, 3 were from Canada and 3 from Australia, while 2 other responders were from European countries. Other than that, our survey tool does not disclose any other information about the people who answered the survey. I am not drawing any conclusions from the information that was collected here, I am simply sharing that information with you so you can gain insight into how frequently, or maybe not so frequently, other breeders may be encountering a similar issue. This is by no means a scientific survey, it is information gathering and sharing only.

Several of the comments that readers posted on the survey concerned the use of Artificial Insemination (AI):

“Seems there are fewer and fewer breeders who breed naturally, even when both dogs are present, or can be present. When faced with a breeder who wants to do a natural breeding, some breeders can’t read dogs or don’t have a clue how to accomplish a natural breeding. How do we gauge natural breeding ability if we don’t allow our dogs to breed naturally? What has happened to survival of the fittest? Seems to me there were issues when we were all doing natural breeding!

Photo by Bob Segal
Photo by Bob Segal

“I’m concerned with breeding “vigor” for lack of another term, and the loss of desire and ability for natural breeding by our dogs. I have witnessed a lack of desire in bitches who are testing out on progesterone. I have witnessed related bitches who would flirt and play, but at standing, would do anything to avoid being bred. No medical reasons were found. These bitches are successfully bred via AI, then carry and whelp healthy puppies. Some breeders say that is enough. But what about the survival of the fittest, should breeding vigor not be included? I am concerned that breeders use AI far to frequently and have lost an interest in knowing how to manage a natural breeding stud dog and brood bitch. I realize natural breeding requires a great deal of planning and expense and some consider flying their dogs to be putting them in danger.”

“When I am breeding a bitch here, I always do an “insurance” AI just prior to the bitch being “ready”. I get a litter on the ground that is nice sized and with a good split.”

Photo by Bob Segal
Photo by Bob Segal

So what did the Gordon Setter survey responders tell us about the frequency of Artificial Insemination (AI) and other similar topics?

76% said their preference is to do natural matings assuming both the dog and bitch were ready, willing and able while 24% said that their preference is to do the mating by AI. (So while for some the preference is to do an AI some of those same breeders will agree to do a natural breeding if the other owner insists.) There were 12% of the responders who said they would not do a natural mating, they will only perform an AI using their dog or bitch. On the whole 88% of the Gordon Setter breeders who responded are willing to do natural matings even if that is not their personal preference.

When we look at the results then, as to the number of matings that were actually completed by AI as compared to the number that were completed by a natural breeding we find that the poll seems to be split almost 50/50 with just over half of the actual matings that were reported having been done by natural means.  From the answers given, when all was said and done and the mating was complete, 58% of the matings were reported to have been accomplished by natural means which allows that the other 42% of the matings taking place were completed by AI. Now, assuming that more of us are taking advantage of the opportunity to use stud dogs from different geographic regions by use of fresh chilled and frozen semen I do not find that number surprising, do you?

We asked those who only perform matings by AI to share their reasons as to why this is their preference. To prevent the spread of infectious agents between dog and bitch was the reason 16% of those breeders gave. Another 37% told us that it is more convenient than a natural breeding and the other 47% did not specify their reason for using AI only.

On the question of Gordon Setter Health Clearances

Stud Dog Owners – the percentage of Gordon Setter stud dog owners who require proof or documentation from the bitch owner on each particular test or clearance before agreeing to or completing a breeding:

90% – require bitch is clear of Hip Dysplasia

78% – require bitch DNA tested rcd4 (clear or carrier)

78% – bitche tested clear of Brucellosis

53% – bitch x-rayed elbows normal

50% – progesterone tested for ovulation timing

48% – CERF – current exam

38% – physical exam including proof of vaccinations and      clear of parasites

30% – bitch tested CA clear

25% – bitch tested thyroid normal

18% – vaginal culture

13% – vaginal smear to determine timing of ovulation

Brood Bitch Owners – the percentage of Gordon Setter brood bitch owners who require proof or documentation from the stud dog owner on each particular test or clearance before the breeding occurs.

93% – dog must be clear of Hip Dysplasia

76% – dog DNA tested rcd4 (clear or carrier)

70% – dog tested clear of Brucellosis

54% – dog x-rayed elbows normal

52% – dog is CERF – current exam

33% – dog tested CA clear

33% – thyroid test

Comments that were posted by Gordon Setter breeders who participated regarding additional exams or clearances that are in use by them, along with some other miscellaneous items that you wrote to us about.

“I don’t believe in vaginal cultures but I do put my own bitches on Baytril as soon as they come in season and stop the day of the first breeding. I discuss this with any potential bitch owners as well. I do sperm analysis on my boys prior to any breeding.”

“Vaginal culture for my bitch and of course Progesterone testing.”

“SLO”

“Superchem CBC Urinalysis”

“You listed thyroid for the stud, but thyroid normal for the dam, there is a difference. I want to see that the testing is done but don’t rule out breeding to dogs with abnormal results. Same thing with CA carriers”  (Note:  that is right and a good catch thank you. I did list the questions this way and it was done in error as I meant to use thyroid normal for both.)

“My bitch gets an exam to make sure she can have a natural breeding. It was determined through this exam that she could not and we did the AI.”

“Using frozen semen and a surgical implant presents its own set of possible complications.”

“If the stud dog has passed away and have only frozen semen I will not breed to a maiden bitch. I will not be told by their vet how many straws are needed, will go by history of prior breeding of the stud dog and by what the company says who has the frozen semen storage (from now on).”

“Using chilled and frozen semen more (often) because there is a wider gene pool available for breeding.”

“I am assuming you are referring to AI as fresh/chilled only. Don’t have the same option when located in remote places or with tight quarantine rules – frozen may be the only option…”  (Note:  the intent of the survey was to try to determine how often matings are being done by AI no matter what the reason (fresh, chilled or frozen) and then to find out how many times breeders are making an actual choice to do an AI when it would have been possible to do a natural breeding with both the dog and bitch available. I expected to find that the number of AI matings would be higher than they were, say 20 years ago, because of the use of fresh chilled and frozen semen to accomplish long distance matings.)

Gordon Setter breeding complications, how often, what are they? How did breeders respond?

Breeders responded to the survey regarding 80 Gordon Setter matings where it was known that the breeding included only properly deposited and viable sperm and it was indicated that 61% of those matings resulted in conception. That means in 39% of the matings the Gordon Setter bitch failed to conceive. Breeders weren’t always able to identify why their bitch failed to conceive, when they did we were told that 25% failed for various hormonal reasons, 17% identified a bacterial or viral infection, 8% found thyroid abnormalities, 8% had structural problems and the remaining 42% fell under “other” or unknown causes.

Of the live litters that were born breeders told us that 79% of the time there were at least 3 or more live puppies in those litters. When asked the question regarding the frequency of stillbirths in litters breeders reported that about 14% of the time the number of stillbirths was higher than they would have expected. In another 10% of the litters that were born breeders reported that there were an abnormal number of puppy deaths in the first 3 weeks of life.

Some breeders did share information regarding the causes puppy deaths during those first 3 weeks. Their comments follow along with other questions and observations:

“Undiagnosed Mastitis”

“Herpes Virus”

“C-Section, dam’s incision dehised,  6 out of 9 puppies died after being removed from the dam and bottle feeding started. (note – “incision dehised” sounds like a wound dehiscence which is a surgical complication where the wound ruptures along the surgical suture).

“mother laid on pup 2 days after birth”

“one puppy #12 came out without a sack and could not revive him, #13 came out with no problems and this was the last puppy of the litter”

“one to respiratory infection (aspiration of fluid) passed at about 10 days, another from extremely low birth weight passed away at 12 days”

“Previously (before the last 5 years) I had a bitch that reabsorbed part and all of her litters. This was due to low progesterone after conceiving. I was able to maintain a litter with progesterone injections. I kept and bred a puppy from this litter and eventually bred her. She also had the same problem, when I kept one of her pups, it too carried the same problem. All were spayed and I started over with an unrelated female. The other problem with the injections is that the bitch will not go into labor, therefore a C-section is a must. A friend had the same problems with one of her Standard Poodle bitches, and the same results with breeding offspring. She had bred Standards for 40 years, her bitch was from her own line, she had never had this problem before, but once it appeared, it seems it is passed on to the female offspring. Neither of us tried breeding a male from one of these bitches, so don’t know if there was any effect on them.”

“No bitch or stud dog failed here, I give vaccinations or medications like Drontal or others to pregnant bitches. Only before mating she’s on the top of health…when the bitch starting her season she received worm cure, vaginal culture and is not allowed to swim in natural rivers…”

“I did have a bitch who conceived but then reabsorbed her litter. She was confirmed pregnant via ultrasound at 28 days”

“Hearing more Gordon bitches with cystic ovaries that fail to conceive”

So my friends, now it’s time for you to chime in, offering advice and further comments using the comment section. This can be a great place to start conversations, ask questions, provide advice and all those other great things we like to do for each other. Looking forward to your participation!

Many thanks to Bob Segal for the adorable puppy photos!

Sally Gift, Mesa AZ

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Breeding

Food for thought… why can’t I get any puppies on the ground?

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Photo by Silvia Timmermann

I was talking with another breeder this week about the “state” of Gordon Setter litters, the quantity of litters being produced as well as size of the litters surviving. The conversation centered around the observation that overall, the Gordon Setter breed appears to be experiencing a decrease in fertility as well as in the viability of newborn offspring. Fewer breedings are taking, fewer puppies are surviving. As breeders I believe we all (yes, I include myself) need to hold ourselves responsible for understanding what may be causing the creation of fertility issues and for the creation of their solution. It’s been said many times by numerous authors before me, when choosing a breeding pair we must consider the fertility and nurturing qualities of the sire and dam in addition to every other trait we consider desirable. To do that, breeders need to understand pedigrees and how they speak to us about the inbreeding coefficient of the litter –  as that coefficient my friends, can drive what is known as “inbreeding depression.” To eradicate inbreeding depression we first need to learn how to identify it and when it appears we need to acknowledge that this could be at play and then we need to plan our breeding accordingly.

I’m not a geneticist and I won’t ever pretend to be, luckily though I am a voracious reader, and with all of the information at our fingertips on the internet today I can find a wealth of expert information for my own, as well as your reading pleasure. I urge you to explore with me, if you’ve not already done so.

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Photo by Silvia Timmerman

First let’s understand what’s meant by inbreeding. Inbreeding would be the breeding of related dogs who may be closely or distantly related to each other. Some, including me, designate inbreeding as close relationship breeding, like mother-son, father-daughter, sister-brother, and call “less close” breeding like a nephew-aunt breeding a line-breeding. But when reading articles written by the genetic expert you’ll find that it’s all packaged together under the name inbreeding. Don’t let that confuse you. With that said, if inbreeding is used carefully as part of a breeding plan that includes balancing the benefits with the dangers it can be a powerful tool. Using inbreeding without consideration of both positive and negative effects can be destructive.

Now let’s go back to inbreeding depression and talk about how that is related to the opening subject of decreased fertility in Gordon Setters and viability of newborn offspring. Inbreeding depression is not about an increase in the number of genetic disorders in the breed, like PRA for example. It refers to a loss of what a biologist would tell you is called fitness. Fitness in this context refers to the dog’s ability to pass on its genes to the next generation. So to a biologist, if a dog dies from disease before it can reproduce it has a fitness of zero. If a bitch successfully reproduces a litter but won’t properly care for her offspring (which will die without intervention) she has a fitness of zero. To breeders like us then, if our Gordon Setters have a high level of fitness they will produce offspring that can go on to reproduce themselves and perpetuate their genes in the population, where a Gordon Setter that cannot reproduce (without human intervention) or reproduces less effectively (below average litter size for example) have a low or zero fitness. In the Gordon Setter breed we could be experiencing evidence of inbreeding depression if we are in fact seeing an decrease in fertility and a decrease in litter viability. Evidence of inbreeding depression can be indicated by singleton litters, decline in conception rates, reduced sperm count, reduced litter size, lower pre and post-natal survival rates, shorter lifespans, higher cancer rates in young dogs, allergies, and many other issues that we might be taking for granted as normal in dog breeding these days. The “fitness” of the dog should be kept in mind as we make breeding choices.

My next step is to send you to some very informative articles I found at The Institute of Canine Biology (as I said earlier I am not a geneticist and won’t pretend that I can write in-depth articles about this topic). What a wonderful resource site!

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Photo by Silvia Timmermann

(Quick note – the photos included in this article are simply for your viewing pleasure, they have nothing to do with the content of the article).

Now, “don’t go throwing the baby out with the bathwater” my friends – that’s not the message here. Oh,and don’t forget to pass it on! Your comments, questions and suggestions are always encouraged in our comment section.

Sally Gift, Mesa, AZ