Health officer : Ms Janis Pennance
Northern Counties Whippet club has appointed a Health officer to monitor the health of our breed, please contact her with ANY health problems you may experience with your whippet, this will be of great help to the future health of the breed.
Jan can be contacted by email at;
The whippet is generally a long-lived healthy breed, they are still used for the purpose for which they were originally bred, an efficient hunter of rabbit, a racing dog, a lure-coursing dog, and even an agility and obedience dog. Truly a versatile breed kept free from any physical exageration that can lead to poor health.
When looking to purchase a whippet puppy it would be wise to look for a breeder who is a member of one of the Whippet Clubs, the clubs have a code of ethics to which all their members should adhere.( The Code of Ethics is printed on the previous page ) This should go a long way to ensuring a good relationship between a prospective owner and the breeder
In December 2008 The Kennel Club asked that each Breed Club appointed its own Health Officer in order to monitor the incidence of any health problems and report these to The Kennel Club. The clubs were also asked to report the most often encountered conditions in the Breed
Although the whippet is on the whole a healthy breed we cannot afford to be complacent as whippets can be affected by certain conditions, this does not mean they are commonplace but that they have been reported in the breed. The Health Survey conducted by the Kennel Club in 2004 reported cardiac (heart) problems in their many forms to be the most common cause of death after old age, followed by immune-mediated diseases. Both of these conditions will be covered in more detail on the following pages
The Whippet Breed Council has appointed a Health Co-ordinator who will collate all the information currently being gathered by the individual breed clubs and this will then be discussed by the Breed Council and forwarded to the Kennel Club
If you would like more information on Health matters in the breed or to report a health problem then please contact me at; [email protected] or tel 01270 624387
Links to Sites and articles of interest
The articles and links reproduced here are not intended as a substitute for professional veterinary care, if you have ANY heath concerns with your WHIPPET then please consult your Veterinary Practitioner FIRST, the breeder of your whippet may also have expert advice to offer so please keep them fully informed of any concerns you may have.
http://www.thekennelclub.org.uk/download/1642/hswhippet.pdf KENNEL CLUB HEALTH SURVEY RESULTS 2004
HEART DISEASE ARTICLES
A recent study has been undertaken to determine specific echocardiogram values in whippets, this may assist in veterinary diagnosis of murmers in whippets which may be within an acceptable range for the breed. The paper is too detailed to reproduce here but if a copy is required please email health officer.
http://www.bsava.org.uk/vcs/testing/general.htm HEART TESTING BSAVA
http://www.bsava.org.uk/vcs/testing/doppler.htm LIST OF SPECIALIST VETS BSAVA
NATURAL HEALING AND FEEDING
http://www.helios.co.uk/ HOMEOPATHIC MEDICINES
http://www.landywoods.co.uk/ NATURAL FEEDING
KIDNEY DISEASE ARTICLES
http://www.dogaware.com/kidney.html#protein KIDNEY DISEASE
AUTOIMMUNE DISEASES...... ARTICLES
GENETICS AND THE IMPORTANCE OF DIVERSITY IN BREEDING
CLICK ON GENETICS 1 AND 2
The following presentation by Geneticist Natalia Bialokoz , highly acclaimed at the Whippet Congress is reproduced here....
At the edge of extinction – gorillas, tigers, blue whales and… whippets?
Would Noah save gorillas?
One or two centuries ago people had completely different thinking about the nature, wild animals, environment and humans’ place in it. It was a strange time. On one hand, the technical and scientifical progress was amazing, never seen before. On the other hand, thinking about nature and wild creatures was exactly the same as in Bible times. People were thinking they had rights to simply own any living creatures on the world and make the best use of them. And, in many cases, did not even bother to think, if any damage is done. In fact, they were not able to believe they can destroy a species, especially a numerous one. History showed it was more than possible and several species counted in millions are now extinct. There was another reason people did not worry much about species conservation. It seemed to them that all that is needed for a species to survive is a pair of breeding animals that given good conditions will multiplicate into unlimited numbers. It was a very simple, intuitive thinking about that, dating back to the beginning of civilisation.
The Lord then said to Noah, "Go into the ark, you and your whole family, because I have found you righteous in this generation. Take with you seven pairs of every kind of clean animal, a male and its mate, and two of every kind of unclean animal, a male and its mate, and also seven of every kind of bird, male and female, to keep their various kinds alive throughout the earth.
This short fragment of the Genesis shows this kind of approach to conservation issues and species survival. Unfortunately, many species did not last long enough to wait until human thinking changed. Although some people still believe that saving only one breeding pair is good enough to save a species, we generally accept the fact, that the truth is different. One pair, or even seven pairs, as was precautiously advised with more “worthy” species is definitely not enough. We now know that a few hundreds individuals, or sometimes even a few thousands, may be too few for a species to survive safely.
Many very well known endangered species are counted in hundreds, or even several thousands, but now, knowing more about the mechanisms of population genetics we know they are at the edge of extinction. Here are some examples:
Mountain gorilla – about 720 individuals left worldwide
Siberian Tiger – about 500
Gavial – about 800
Blue Whale – about 5000
How many individuals is needed to ensure survival depends on many things, like environment, average longevity, the length of reproduction cycle, number of progeny for one pregnancy and many other conditions. However, using sophisticated computer software, we are able to calculate the lowest number, which enables survival of the population of interest. It is called “minimal viable population” in genetics. It is worth knowing, that when calculating this number, we check what is the minimal number to last for 40 more generations from now.
The exact number is different for different species, but a rough estimate for mammals is often said to be around 4000, although some say it is around 7000 breeding individuals. Let us take the optimisitc approach, 4000 individuals. If a population size is below that number, we know it is in great danger of extintion. Probably without very intensive help and without special actions intended to safe it, it is doomed. The term “minimal viable population”, although intended to describe wild animals’ populations can be easily used for domestic animals, breeding only within some finite populations, exactly like purebred dogs, whippets for example. Very many breeds are so rare we can be sure they are at the edge of extinction in genetic terms.
“But definitely not whippets!”
One could say at that point – “But what are we talking about? Aren’t whippets much more numerous? We have many thousands of them around the world!”
And, unfortunately, he would not be completely right. Yes, it is the fact – there are many whippets around the world. For example, in Sweden only, during last 10 years 626 litters were born, 3383 dogs, which is roughly equal to the number of bredable animals during these years. Huge number, considering it is only one country’s population, and not even the most numerous. However, only 298 males and 436 females, 734 dogs in total, were used in breeding at the same time – it is only a tiny part of the whole whippet population, approximately 21 per cent. The rest, from genetic point of view, could not exist at all. We should think only about the ones used in breeding at least once, when talking about the size of whippet population. Moreover, because of breeding practices, this population is far away from what could be expected in nature – the dogs are inbred, many of them carry the same combinations of genes.
The ideal population, which is a model for population genetics, would be completely different. In such a population
- there is no selection of any kind
- every animal has statistically the same chance to have progeny
- males and females contribute equally to next generations
The ideal populations have great genetic diveristy, many combinations of genes, good resistance to infections and diseases and good ability to adopt to changing environment.
It is not hard to notice that whippets population is completely different from the ideal one.
- the selection is very hard, based on show or working quality
- only very few, artificially selected animals are allowed to breed
- there is a huge difference between number of males and females contributing to next generations (By the way, this feature is characteristic of a dog as a species Canis familiaris. There is a strong genetic evidence, that the very first types of dogs, formed many thousands years ago, were created by our ancestors in exactly the same way – single males were used intensively to fix desired type.)
In ideal populations every animal’s geneset is unique, combinations of genes does not repeat more than it is expected statistically. In inbred populations the opposite is true – the whole combinations of genes repeat in various animals. Because of that some animals do not add anything to the population in genetic sense – all they could offer is already there, in other dogs. They are not “effective” members of the population.
To deal with such populations, the geneticists evaluated the algorythm to calculate the number of unique individuals with genetic diversity equal to an inbred population of interest. It is called “effective population size”. This number tells us, what is the real genetic diversity in the population. Calculating this is a very complex problem, as we need to take many things into consideration, there is a special mathematic formula for that. All details are not necessary here, but there is a simple conclusion coming from such calculations – the effective population size is never higher than 4 times the number of males used..
In Sweden, during last 10 years, only 298 males had litters. It gives the effective population size of 1192 genetically unique individuals. So, ca 2/3 of population is “ineffective”. And, as was said before, only about 21% of them are breeding population in reality, due to breeders’ selection for show or working goals. So, considering both genetic point of view and our artificial selection, eliminating most dogs from breeding pool, we get the number of about 250 dogs. This is the whole Swedish population, only about 7 per cent of all whippets being born in Sweden. And it is similar in numbers in all other parts of the world. Moreover, it is important to say that Sweden has relatively low average inbreeding coefficient and uses many males. In countries where whippets are less popular, or where close inbreeding is more common this percentage can be even lower. 250 dogs - this number brings us dangerously close to the minimal viable population mentioned before
Diagram: red square = all whippet born in Sweden; orange rectangle = dogs which passed breeders’ selection; green rectangle = the number of genetically unique individuals; common part of green and orange = the real effective population in Sweden
And this brings us back to endangered species we have started with – whippets, being such a numerous and worldwide spread breed are in fact in situation of a rare, endangered species. Of course, we have advantages – we have veterinarians, we have best food and best care for our dogs. But all that can not be enough, if we do not stop disregarding biological consequences of our breeding practices. We have grown up from Noah’s thinking about other species at risk of extintion. We have complex and well planned programs created to save many species of animals, keeping as much of their diversity as possible and giving them best chances possible for future, although it is often hard to bring them into effect. Should not we use all that knowledge for our beloved whippets as well? There is no reason for treating whippets worse than, let us say, gorillas.
Inbreeding and wine
It is worth mentioning that from a genetic point of view inbreeding is any mating between animals that have common ancestors. Defining some kind of it as “inbreeding”, and some other as “linebreeding” has no reason other than just a custom. And it is not a good custom, as it may suggest that when “linebreeding” one does something completely different, without the effects of inbreeding. Thus, any time, when the word “inbreeding” is used, it is to be understood as “mother and father have some common ancestors”.
There is a very strong scientific evidence that inbreeding has negative effects both on single individuals health and on the whole populations welfare. It may be hard to believe we are facing any problems at all. At the moment whippets are a numerous, relatively healthy breed without evident problems. But it is important to be far-sighted. We have so many examples of unbelievable numerous species, counted in milions, and yet extinct, because no-one believed it is possible to annihilate them. Far too many.
It is worth remembering, that viable population size is a number of individuals capable of surviving for 40 generations. At the moment many dogs, depending on the pedigree, are 20, 25 or 30 generations at the very most from breed foundation. Surviving next 40 generations means longer way than we have already gone through.
It is said that our breed is in so good condition at the moment, and any health problems are so rare, that there is no need for any special action against them. Although it is heard here and there that somewhat more health problems are reported recently than years ago. And it is generally true, whippets are a healthy breed. But it is also worth knowing, that if any health problem is developed in even few animals, far larger number has it in genes, carrying the bad gene without any sign of it. For example, if only 1% of dogs has PRA, as much as 18% is carrying the gene for it. It is true for any other genetic disease present in the breed. Every individual is expected to carry 4 or 5 defective, deleterious genes. And there is no escape from that, every single individual is carrying them. Some may carry more, it is especially possible if they are highly inbred.
Sometimes it is also said, that there is absolutely no need to change breeding methods, as so many breeders before were using them with great success, and never encountered any problems. Constant inbreeding is said to be the best or even the only method to aquire show quality. Unfortunately the reality is not as problem-free at all.
Inbreeding has a lot in common with drinking alcohol. Drinking one or two glasses of wine is safe for almost everyone, does not bring any unpleasant effects and may add something special to a meal. Many people will not feel any bad effects after drinking third ar fourth glass, too. But there is no-one, who can drink unlimited number of wine and still not have any bad effects because of that. If one chooses to drink something stronger, like vodka instead of wine, the negative effects are to be expected even quicker.
With inbreeding it goes exactly the same way. In most cases, mating related indiviudals once, or even two times in a row does not cause any visible bad effects. In some cases even the third or next matings seem to do no harm. And again, as with alcohol, the stronger option (closer related animals) you choose, the quicker the effects can be expected.
Proponents of tight and repeated inbreedings sometimes say something like that: “we have been doing that for generations and the breeders before us were doing it, and there is no bad effects, only good – so it is safe to continue this way”. This is similar to someone talking “I have drunk 4 glasses of wine, it feels wonderful and I have no unpleasant effects – so I have proven that drinking as much is completely safe, I can safely drink another 4 or 8 glasses”.
We can go even further with this analogy – although it would be obvious some bad effects can be expected if one drinks a whole bottle of vodka in one evening, he could safely drink the same amount without any bad effects, providing that after drinking one of two glasses he eats and drinks something different, waits for some time – and then, after a few days maybe, drink another glass. This way he probably will never see any bad effects. The opposite is also true – if one drinks too much and too often, negative effects accumulate and even if he stops drinking at all the damage has already been done and he cannot “undrink” what he had drunk before.
In fact, breeding practices from the times of breed founders have their origin in Noah’s attitude to animals and breeding. It seemed obvious that just a couple of founders would be enough to form the breed, and that further multiplication was only a matter of time. Repeated inbreeding was not seen as any problem, as nobody really was thinking about it as something to worry about. And it was really working for a long time.
At present, we do not have the situation the breed founders had. Inbreeding was being repeated for many generations, our breed survived a few seriuos bottlenecks, the most important one during WWII, which caused a considerable decrease in population size. There are several dogs, which can be found in almost every whippet pedigree in the world. Breed founders or even breeders in the fifties of the 20th century were in a different situation. Their dogs were closer to foundation, the number of inbreedings done before them was uncomparable with what we have now. Although it could have been quite safe for them to inbreed a few times more, it is not as safe today. Our breed has already drunk too many glasses of wine.
It would not be very wise to wait until we can see very clearly all that things we can predict now basing on population genetics laws. When they are seen clearly, it will be too late. We are at the very good moment to start thinking about solving future problems. We have many healthy, outstanding dogs, we have many possibilities to make the health situation in the breed better, not worse – and without changing breeders approach, it will not get better on itself.
It is an ideal moment to create and put into practice some breeding practices, which will ensure great future for whippets, not only in the show ring and all the other fields of activities, but in term of genetic health as well.
“Houston, we’ll get a problem!...”
What problems can be expected, if we do not change anything in breeding schemes?
The first one - the population will become more and more inbred, and its effective size will be shrinking again and again. Inbreeding also increases homozygosity.
The second one – so called “popular sire syndrom” will be more and more serious, with some dogs’ genes spreading so widely, that it will be very difficult to find any dog unrelated to such a succesful sire. We have some examples of that already, great dogs from the past who stamped the breed so strongly that are present in any whippet pedigree in the world. Unfortunately, this also means that any bad genes carried by these wonderful dogs are widely spread in population, even if they were very rare at their time. And, as was said before, there is no dog without bad genes.
These two things will have very important effects on the whippet health as a breed.
We can expect some genetic diseases to be more frequent than in the past, as more dogs will be homozygous for the genes causing these diseases. And it is very important to remember, that genetic diseases are not only like colour dillution allopecia, a single gene disease, causing loss of hair in affected dogs – relatively easy to spot and breed against. In fact, so far I have not found any other genetic disease known in whippets with such a simple mode of inheritance. The other conditions are inherited in more complicated way, have late onset, which makes more difficult breeding against them, or the combination of genes does not cause the disease in a simple way, but greatly increases chances of developing it, if an environmental trigger is met. This is a similar situation to cancer genes in humans. There are few, which are known to just cause a cancer, many more, which are risk factors and yet many forms of cancer have completely undefined mode of inheritance, although they are known to be hereditary.
We are lucky to have relatively few known genetic diseases in whippets and few of them are of most serious nature, causing much pain and/or death at early age. However, the ones we have are often difficult to spot, as they are developing gradually over the years, which enables affected dogs to have offspring, even at most caring kennels.
The topic of genetic diseases has been cover well in numerous publications, so I will not go any deeper with that. But there is another, maybe less known effect of increased inbreeding level and increased homozygosity.
Many years ago people used to think that bringing domestic animals as close as possible to complete homozygosity would be an ultimate goal for breeders. It seemed to be so simple – the ideal animal would have all the desired genes for all good features, and would breed true for all of them. Breeders’ dream would come true! However, when people started to put that into practice, it became obvious that this is far more complicated.
Laboratory strains of mice are an example of almost completely homozygous animals. Such a line is created this way – you take two mice, brother and sister from one litter, mate them together, from their litter you take brother and sister, mate them together and so on. After about 40 generations the animals are almost completely homozygous. However, obtaining the goal is difficult, as vast majority of lines created in such a way will die during the process. Accumulation of bad genes will kill them, or they will experience fertility problems which prevent them from continuing the line. Few strains were lucky enough not to accumulate defected genes and these ones have formed the lines we have now.
Some may think they are the best proof of inbreeding as the best method of obtaining a healthy, free from lethal genes line. Unfortunately, it is not completely true. In fact, it is completely wrong. Yes, these strains are free from lethal genes. But every one is labeled with a list of diseases it is prone to (many of the strains were selected to be models for various kinds of cancer) and, what is particularly important – a list of infections it is known not to be able to fight! In fact, these animals have to be kept in very clean, almost sterile environment, fed selected, special food – and yet are very suspectible for infections. What is wrong with them? Their immune systems are malfunctioning.
Years ago researchers had a model, in which every gene in the organism had a natural, fit, common form and maybe some other, defective forms, rarely found in nature. In other words – a great homozygosity was expected in animals, especially in the most important genes, required for everyday cell functioning. Further examination of this problem revealed something completely opposite – the animals are very heterozygous in almost every gene analysed. Most of important peptides in our organisms come in several different forms, although functionally they may be hard to differ. However, we can guess that this variability can be usefull, for example one form can be functional in most situations, whilst another – better when an animal has a fever. Probably we will never be able to find all relations between all peptides in our bodies. Repeating results in such research inspired the idea, that heterozygocity is a good thing by itself.
the most important, and quite well understood now, aspect of heterozygocity is
connected with immunity in a straight way. The immune system depends on
something called MHC (Major Histocompatibility Complex). MHC is responsible for
marking all the cells of one's own body (so that they are not destroyed, marked
as "own, ok") and for marking any invaders that might be in the
organism, like bacteria, viruses etc. (so that can be destroyed by special
cells, marked as "alien, danger!!!").
The problem is that any single cell, whose job is to mark organism’s own cells or invaders can recognize only very few similar patterns. And there are thousands and thousands of potential invaders to recognize, mark and destroy. That is why we have very, very many form of genes coding MHC complex. In humans we have a few hundreds (!) different alles for genes in MHC complex, and every single individual has a unique combination of different forms.
Moreover, the genes for MHC are organised in a very odd way, and the immune system cells are able to mix them and form different combinations of them, which enables marking more types of invaders. Because of that, if one part of the gene is lost, it means that many hundreds or thousands of possible invaders cannot be found, marked and fought.
As any individual has a unique set of MHC genes, it is quite unlikely that an important portion of possible combinations will be lost in random mating. Most individuals are hetorozygous for most genes in MHC complex, i.e. have one set from mother and another from father, being able to mark and fight the invaders of all types. But inbreeding increases homozygosity. When mother's part is exactly the same as father's part, a puppy will have only half of the MHC genes it would have if the parents were unrelated (and have different sets of MHC genes).
That means, that probably it would be able to fight some of diseases quite well, but there will be some diseases it will be not able to fight at all, as it lacks cells able to mark the invader. This is exactly the situation observed in rats and mice strains in laboratories.
The other, but related issue is that immune system marks not only alien cells, but own ones as well. If, by any chance, it's ability to recognize all types of own cells is compromised, some of own cells may be marked as "alien, danger!!!" by mistake. That leads to autoimmune diseases. On the other hand, if MHC system's ability to mark own cells makes another mistake, cancer cells may be marked as "own, ok" and the cancer will develop without any problems. It is known that some strains of mice and rats are especially prone to certain types of cancer (well, they are breed to be prone).
Our purebred dogs have already lost some of MHC complex variability of the whole species just because they are pure bred and have only a part of all canine genes. But we should not cause further elimination of these very important genes.
So, if we do nothing to increase the heterozygocity in the breed, we can expect the whole range of autoimmune diseases will become more and more popular. Conditions such as polyarthitis, autoimmune thyroiditis or different forms of inflammatory bowel disease can be expected more and more often. Veterinarians say that even already a dramatic increase in frequency of autoimmune diseases is observed among many breeds, some say –including whippets.
Immune system plays a great role in fighting against parasites, so dogs with problems in their immune system can have also troubles fighting them, more serious ones than an average dog. Generalized demodecosis is an example of what it can lead to.
What is worth knowing about autoimmune condtions is that a certain defect in MHC can result in various types of autoimmune diseases in affected dogs from the same family – one can have poliarthiritis, and the other, for example, hemolytic anemia.
This relationship between homozygosity in MHC complex and suspectabilty to infections is not only a theory. Besides artificially created mice strains we have several other examples, cheetah being probably the best known. Cheetah as a species survived a very serious bottleneck some time in the past. The cheetahs living today are very homozygous and related so closely, that every individual will accept skin transplant from any other individual, living thousands kilometres away without adverse reaction. Cheetahs are also known to be more suspectible to certain infections. For example FIP, a viral disease not very dangerous for other cats, including our domestic cats is deadly dangerous for them. For cheetah chances that an infected individual will survive are only at the level of 40 per cent, whilst for a domestic cat – 95 per cent. They also tend to be more sensitive to other feline infections than any other cat species, show unusually high number of deformed sperms and experience serious fertility problem in both sexes, having also very small litters for a cat of their size and high level of neonatal deaths. Cheetah is a very instructive example of what too much homozygosity can cause.
It is important to know, that we cannot replace body’s own immune system with medications. In most cases, when we treat a disease, we do nothing to destroy invaders. We help the organism to make more defensive cells, to make them faster and more efficiently, so it will be able to fight the infection better. It is particularly true when talking about viral diseases. However, if animal’s MHC system does not identify invaders, all that help is useless.
Have your cake and eat it
The need for increasing heterozygocity in whippets seems to be the only logical conclusion. And it is perfectly possible to do this, maintainig the style and/or working ability of our dogs. Reading some articles on diversity in purebred dogs one may be left with impression, that to breed genetically healthy dogs, you have to look for the least related dog possible, do not think about show or working successes, and concentrate on the biggest number of unique names in the pedigree. This certainly leads to conclusion, that this is a choice – you want to breed good specimens in terms of shows or working purposes, or you want to promote diversity, you cannot have both. A kind of binary system. It is not true. Even if you are a true believer of inbreeding, you can do something to increase total diversity in the breed. 5 per cent more is always better than nothing, in computer simulations we can see that sometimes that sort of change makes a great difference, even responsible for survival or extinction.
We breed whippets not just to multiplicate the numbers of them in the world. Certainly we have many goals and genetic health is only one of them. It would be silly to produce dogs with an outstanding number of unique names in the pedigree, inbreeding coefficient close to 0,0% - and nothing more. Most breeders want their dogs to be something more than pets only. Most of them also choose studs for their litters among the ones who do excel in some area. So, our theoretically perfect (from genetic point of view) productions could be never born as well, as no-one will ever use them in breeding – and as was said before, only the ones who have progeny are important. Breeding a litter of great genetic diversity and poor quality does not help the breed in a long term!
In fact, constant out-crosses in populations calculated in hundreds are not possible. Or, they are possible, but for a very limited time. We have too few separate lines, to be able to out-cross for a number of generations. If every breeder tries to out-cross as much as possible, in two or three gererations no separate line will be left, as every dog will be a combination of lines existing before. Importing a dog form another country and completely different bloodline would be a solution, but this would undoubtly lead to another case of popular sire syndrom, as this dog would be an only option for all breeders who want to out-cross. Constant importing of unrelated dogs is not possible, as we have finite number of available lines. Some degree of inbreeding is unavoidable.
However, we should remember that inbreeding is something that can cause problems. It should be used wisely and with respect, not just because “it’s the way everybody’s doing”.
Diversity-friendly breeding manual
What would be good for the breed in a long term, if put into practice? What can a geneticist recommend to a breeder who wants to promote diversity? Here are several tips:
Ø Inbreeding should be a tool, not a habit. The sire for next litter should not be choosen just because he is from the same line. Consider quality of dogs and their virtues – if you can get the same from two dogs, one related, and the other unrelated – choose the unrelated one. If one is closely, and another – distantly related to your bitch – choose the more distant family member. Comparing the pedigree, in which all 8 great-grandparents come from the same line, and another one, with only 7 of them coming from the same line, and 1 unrelated we can see a difference in inbreeding coefficient as huge as 7-8 percent! So even a single out-cross, or using an out-cross made by some other breeder every now and then can help a lot!
Ø Close inbreeding, like father-daughter, son-mather, full siblings mating should be reserved for test matings only, or for very rare ocasions, when you need to “dig up” a single reccesive gene and that is the only option. If you want to mate half-siblings by the same male, their mothers should be as unrelated as possible, but have a lot in common in type. Common belief that “it’s safe when done by an experienced breeder” has no reason, unfortunately. Experienced breeder can be expected to achieve better quality in progeny, knowing his stock better, but possible health problems have nothing to do with experience, only with statistics.
Ø Inbreeding in fact can be a valuable tool, and in many cases a quick way to fix some virtues. But always remember that it is also a way to fix faults at the same time. Combining inbreeding with “assortative matings” (which is a funny name for breeding animals looking alike) is the best way to avoid fixing faults (and genetic disorders of course).
Ø Do not be very afraid of losing type, when considering using an unrelated male. The number of genes for every single conformation trait is finite. If one dog has a long neck, and the other, completly unrelated one has the same long neck, it is a great chance they have the same genes for that. And the same genes are exactly the purpose of inbreeding, nothing else. Moreover, if you do get something slightly different in the first generation, it will not take long to return to previous type, breeding back to some distantly related dog in your own line. A very interesting experiment showed that even introducing something as different as a corgi into a line of boxers is unrecognisable after only 3 or 4 generations!
Ø The type of inbreeding which increases homozygosity in the quickest way is when mother and father have not one commmon ancestor, but a whole pack of them. At the same time, it is not more, but less efficient way to obtain individuals possesing the virtues of their famous ancestors. You cannot select for many traits at one time. And you cannot select for exterior similar to a certain dog, if it is not the only dog repeating in the pedigree. In fact, some litters with such “concentrated” pedigrees and many dogs in common, can be very uneven, unpredictable. And similarity in looks is one of the main goals of inbreeding. Importance of choosing one and the only one dog to linebreed to was obvious for great theoreticians of inbreeding, as famous GSD breeder Lloyd Brackett, who used to ask “inbreeding, but to what?”. It is also much better for genetic diversity.
Ø If you have an outstanding dog – it would be good for the breed to refuse mating to a poor quality bitch closely related to your male, but be much more tolerant, if the bitch is unrelated. The latter case gives also more chance for quality progeny.
Ø If you have an outstanding bitch, and strong preference for linebreeding – consider out-crossing her once in her lifetime. You may not want to keep any of the puppies from such a litter, but maybe some other breeder would make a good use of them?
Ø Refresh your memory! When thinking about next litter, consider also dogs retired from rings some time ago, and those shown only a couple of times, but of high quality. If it means mating to an elderly dog – it is a wonderful news really. You can be sure he is fit, in good condition to an old age, without genetic diseases with late onset. You can expect the same with his puppies – this is something you can only hope for when using a 2-y.o. dog. Dogs with “older” pedigrees can also be valuable as source of some rare genes, maybe lost in next generations. Think about brothers or cousins of the top winner you consider as sire – maybe they can offer the same you want from this winner, but where not overused?
Ø In every country it is easy to find one family of dogs, which dominates show rings and breeding pool. Now, when the world has shrunk so much and importing dogs became much easier, it is even visible in the whole whippet population. If you have bitches from an old line, unrelated to the current “mainstream”, treat them as rare treasures, and try to conserve this line as long as possible. Do not ban them easily from breeding pool, and, when possible, try to find a stud outside this mainstream at least once in their lifetime. They can be the only source of genes absent in other lines.
Ø When deciding on the stud, check old lines unrelated to mainstream twice, before you decide on more popular family. These old lines are precious, and losing them will be irreparable. It is especially important in English population, which has the greatest diversity as a country of origin. If you are thinking about importing a dog from another country, try to look among the ones outside the mainstream. Sometimes they may offer everything you need in terms of conformation, and genetic diversity as a bonus.
It may seem that following paths determined by population genetics is hard, troublesome and less efficient than chosing a common way, accepted for such a long time. Like taking a narrow, bumpy path instead of wide, comfortable road. But all depends on attitude. Years ago nobody would have expected, that some time in future so many people would select waste for recycling, or buy more expensive kitchenware because it consumes less energy. Human thinking changes in many aspects of life. It can be expected, that breeding animals is one of the next of them. Even the most narrow and bumpy paths eventually change into motorways, if many people use them.
The internet is rich in valuable resources covering various aspects of population genetics and breeding purebreds.
Here are some suggetsions:
Canine Diversity Project – a great site with plenty of information in a well-organised form. Started by late Dr John Armstrong, a geneticicist from Canada - http://www.canine-genetics.com/ His article “The Poodle and the Chocolate Cake” is most worth reading, as well as very informative articles by Dr Helmuth Wachtel (including “Breeding dogs for the next Millenium”) and James E. Seltzer’s paper discussing the need of inbreeding (with a very interesting analysis of the level of inbreeding in top winners and top studs).
Purebred Dog Breeds into the Twenty-First Century: Achieving Genetic Health for Our Dogs – a series of articles by Dr Jeffrey Bragg, in-depth analysis of breeding methods, valuable observations and good advice - http://www.netpets.com/dogs/reference/genetics/bragg.html
Great choice of articles by a British geneticist, Dr. Bruce Cattanach of Steynmere Boxers, with “Breeding for success - What the records show” (analysis of inbreeding levels) and a truly wonderful history of bringing a bobtail gene from corgis into boxers, with plenty of amazing pictures – a MUST for everyone afraid of losing type when out-crossing - http://www.steynmere.com/GENETICS.html
The Rising Storm: What Breeders Need to Know about the Immune System by C.A. Sharp – a good and easy to understand paper covering immunity issues - http://www.alachealth.org/mhc.htm
Genetics And Breeding Strategies: Essays For The Dog Breeder – a series of essays by Dr. Susan Thorpe-Vargas, covering many topics from the field of genetics - http://pawpeds.com/pawacademy/genetics/breedingstrategies/
Natural Protection of Genetic Variation by Dr Per-Erik Sundgren, very well-written paper discussing genetic diverisity and its results - http://pawpeds.com/pawacademy/general/naturalprotection/