Breeding coefficients

[Fran Griffin]

Just out of interest, I have just been looking at the inbreeding coefficients of some of the litters currently available and have discovered that many of them are way over the breed average of 13.4  one litters coefficient is way over 25.

I am wondering if breeders are bothered that they are producing litters with these results? If not can somebody please explain to me, as a Setter pet owner why this is so?  If I was currently looking for a puppy, these kind of results would make me look elsewhere.

[Margaret Sierakowski]

Another excellent, although longer, article by Jeffrey Bragg

http://siriusdog.com/genetic-health-dogs-bragg.htm

[Catherine Carter]

Thanks for the link, Margaret!

I am printing the paper by Jeffrey Bragg and will digest it this evening.

[Margaret Sierakowski]

Another interesting piece of research to read , if you can get access to it online without paying, is "Inherited Defects in Pedigree Dogs Part 2: Disorders that are not related to breed standards" byJennifer Summers, Gillian Diesel, Lucy Asher , Paul McGreevey , Lisa Collins , published in the Veterinary Journal Vol 183 in 2010

The researchers took the top 50 most popular breeds by registration numbers, which included Irish Setters. They identified 312 non conformation linked genetic disorders in these breeds, 71% of these disorders are autosomal recessive, and most affect a number of different breeds. The Irish Setters ranked 13th for the number of genetic disorders affecting the breed with a total of 44(33 non conformation related), but when weighted for severity of the disorders, Irish Setters rose to 3rd place

The researchers said that in breeders with smaller registration numbers, inbreeding plays a larger part in the extent of genetic disease. The research was funded by the Dogs Trust

The research didnt include the other setter breeds

[Margaret Sierakowski]

Thats fairly simple, Greg, what geneticists are seeing is that as genetic diversity is lost in dog breeds  and they become genetically more homogeneous, the number of identified genetic diseases rises and the rate at which genetic disease spread through the breed accelerates. Add to that the effects of inbreeding depression

An area that hasnt been researched much, but which is touched on by Jeffrey Bragg, is the importance of female lines for healthy breeding, because mitochondrial DNA is inherited only though the female line. Where the preoccupation is with the  use of popular sires rather than strong  female lines, that also affects the long term health of the breed. Sheepdog breeders have always maintained strong bitch lines, going out to unrelated stud dogs, knowing that was the way to breed good healthy working sheepdogs.Breeding on bitch lines of course also helps to maintain diversity as each bitch produces only a very small number of litters, compared to the limitless litters one stud dog can produce

Mary Roslin-Williams understood this too, although not in modern genetic terms, if you read her book Advanced Labrador Breeding , you will find  her bitches were the cornerstone of her breeding, she even culled dog puppies from her litters to ensure her bitches grew up as strong and healthy as possible

 

[Susan Stone]

Thank you Margaret, would love to read the article in full...

[Nardi Rowe]

I know this is not dog breeding but the Arabs produced very fine horses used by most breeds around the world including the Thoroughbred to improve their stock.  Purity of the breed, stamina, courage, intelligence, strength, temperament were virtues they highly prized.  Their horses being used primarily as war horses to ride to attack other Bedouin tribes.  The Bedouins placed their importance in breeding on the female tail line.  I have read that the mare contributed 60/40 to her foals according to them some writings even higher.  There are 5 main strains.  A pure bred Arabian foal is registered according to its dam's strain.   Now with the allowance of embryo transfer in Arabians worldwide we are going to lose many important aspects of breeding such as gene diversity, the ability of a mare to get in foal naturally, carry a live foal to term and raise a healthy foal.  Sadly money (and ignorance of breeding for the long term in some instances) has more sway these days.   AI had already reduced the diversity of the breeds gene pool as local stallions (even though many are excellent) are rarely used if a mare owner can afford to do AI from show winning stallions including importing semen from overseas from very popular, heavily used stallions.  I hope I haven't gone too far outside this discussion.

[Margaret Sierakowski]

The research was based on KC registered dogs. The only people who  keep ongoing figures on the incidence of disease in non pedigree dogs are the pet insurance companies . And crossbred dogs are in the lowest payment band for pet insurance based on actuarial costings. Some pedigree breeds can cost four times as much for pet insurance as a crossbreed because   their veterinary bills . A lot the cost of is to do with recessive gene conditions, the cross bred dogs may carry a gene inherited from a pure bred parent or grandparent but the gene isnt expressed (unless it happens to be a condition common to two or more  breeds in its ancestry). They are also less prone to autoimmune related diseases.

There is a lot of silly talk about how cross bred dogs like labradoodles suffer from poor health because their breeders dont health test like pedigree dog owners do. It isnt borne out by the actuarial research of pet insurance companies. And unfortunately there are a lot of pedigree dog breeders who dont test either, and plenty of health problems that cant be tested for. Look at Irish Setters, according to the recent research I quoted yesterday, they have 44 known genetic diseases , but only a very small number for which there are DNA tests like CLAD, PRA and rcd4. And they are likely to be  in a higher band for pet insurance than a labradoodle!

And I'm not an advocate or apologist  for designer dogs! I much prefer a KC registered dog bred for a specific purpose .

[Margaret Sierakowski]

To give you some idea of comparative pet insurance costs, Tesco pet insurance will insure your crossbred dog for £8.29 a month for the most basic cover , but a setter will cost you £14.73 for the same level of cover

[Fran Griffin]

Thank you everyone for all your comments so far, I am gaining a lot of information from this, and thank you to the person who has provided me with some very interesting information concerning relatives of my Tallulah, including what they died of, which is providing me with some very interesting information, particularly as a certain line links back to a couple of my old dogs, who likewise died of auto-immune conditions. How interesting......

[Susan Stone]

Inbreeding and the problems of high COI certainly affect most breeds and I was interested to read in the Swiss Kennel Club's magazin 'Hunde' about research that has recently been done for the traditional Swiss Breed 'Entlebucher Sennenhund' and 'Appenzeller Sennenhund'. I doubt if many have even heard the name of these breeds, so you can imagine that their numbers worldwide must be quite small... !

You may be interested in the findings as the approach and the way of dealing with the problem to me seem exemplary.

I have tried to write a resume of the german article from 'Hunde', written by Dr Iris Margaret Reichler of Vetsuisse-Facultät Uinversität Zürich with funding from various organisations like breed clubs and the Albert Heim Stiftung:

Over recent years an increasing number of Entlebucher Sennenhunde were thought to suffer from incontinence, but clinical diagnosis showed that a majority of these dogs suffered from ectopic ureter - a malformation where the ureter does not terminate in the bladder. According to the author this problem has been found in other breeds besides the Entlebucher Sennenhund, ie the Golden & Labrador Retriver, the Briard, Siberian Husky, and some Terriers.When a condition appears more frequently in certain breeds than in others it must be assumed that the problem is genetic.

A clinical study was set up to screen a large number of Entlebucher Sennenhunde, not just in Switzerland but in vet clinics in different countries like Germany, Austria and the Netherlands. At the time of screening healthy males were required to donate sperm for freezing to enable the possible use of this in future breeding programs once a genetic marker had been found and carriers or clears could be identified. 298 Entlebucher Sennenhunde and 67 Appenzeller Sennenhunde were found to be affected. This meant that only 36% of the Entlebucher Sennenhunde were clinically healthy, wheras 84% of the Appenzeller Sennenhund were not affected. Of the affected dogs not all suffered from the same severity of symptoms. Considering the fact that the two breeds go back to the same founder animals and have been bred separately since 1914 it is not surprising that both breeds are affected, although not to the same extent.

Geneticists (Dr C. Schelling, Prof. G. Dolf, Prof. T. Leeb) then tried to define the possible mode of inheritance whilst also taking in consideration possible influence of other outside factors. The analysis confirmed that there could be two main recessive genes responsible for the illness but still the mode of inheritance must be assumed to be complex. It is most important to avoid restricting the genetic varibility any further or else the level of inbreeding will rise - with all the negative consequences.

The aim obviously is to find a genetic test for ectopic ureter so that affected and carrier dogs can be identified. Then a breeding strategy must be developed that allows to reduce the incidence of ectopic ureter without further depleting the gene pool  and thereby massively increasing the risk of new inherited diseases becoming apparent.

 end

In what way does this affect Setters? It goes to show that a low Effective Population Size together with a high COI will increase the risk of genetic diseases becoming widespread in a breed, and once widespread there is no quick and easy solution.  DNA tests (if available) must be used with careful consideration so as not to decrease genetic variability any further.

No living being is free from deleterious genes and trying to 'breed out all bad genes' is simply not possible.

[Margaret Sierakowski]

Over 60% of the Entlebucher Sennenhund are also affected by Posterior Polar Cataract. The breed wisely decided some years ago that they could not afford to discard the affected dogs from their breeding stock. They have no DNA test in spite of years of research looking for it. So they have to rely on breeding affected dogs to apparently clear, or clear to clear. But its another example of how a genetic problem can spread widely across a small breed with a low effective breeding size

[john murphy]

Calculating COI's (using Hooley's pedigree search) for RCD-4 clear and affected Irish setters as provided on the Kennel Club Site (rcd-4 CLEAR - http://www.thekennelclub.org.uk/download/11673/irishsetterpra4clear... and rcd-4 AFFECTED - http://www.thekennelclub.org.uk/download/12109/irishsetterpra4affec... ) the following data was obtained, which i think speaks for itself...

 

COI	Clear	Affected	Total		% Affected
0 to 9.9	41	1	42		2.4%
10 to 14.9	106	16	122		13.1%
15 to 19.9	93	25	118		21.2%
20+	62	14	76		18.4%
Total	302	56	358		15.6%