How do we calculate COI?

There’s been some discussions recently as to why iwdb shows different (lower) values of inbreeding than some other systems. We would like to take the opportunity to explain how we calculate Coefficients of Inbreeding (COI), how that differs from Wright’s formula for doing the same thing, and why we’ve chosen the method we have.

When describing any inbreeding, it’s necessary to calculate the distance between all ancestors being present on both sides of the pedigree. This is done through a normal path-counting method, counting the distance in generations from the appearance on the sire-side and the appearance on the dam-side.

This is what IWDB does. When Sewell Wright constructed his formula in 1922, he also added that the COI of the common ancestor itself should be added to the calculation. This is the way it’s done in most pedigree-programs, but not in IWDB. Thus IWDB will report a somewhat smaller

There are technical reasons for our choice to omit additions of common ancestor COI. IWDB calculates COI on anything from 3 through 10 generations. In order to include ancestors COI, we would have to store the COI of all dogs that were bred from in the database in 3-10 generations. In order to provide accurate and fast calculations for trial matings, we would have to include all dogs in the database in this dataset as well as COI of all trial matings. The COI would have to be recalculated for all descendants any time we add an ancestor to the dataset. All of this is very time consuming. Typically, in the neigbourhood of 30 minutes each time it’s done.

What difference does it make? It varies a lot and all depends on the ancestors, their inbreeding and their usage. IWDB will normally report a bit lower COI (Anywhere between 1-3 percentage points) than other programs.

We are comparing apples to apples, though, so when comparing to breed averages, the calculations done are the same.

Contribution of blood

We have added Contribution of Blood as a value in the ancestor-listings of IWDB. Interpreting these data is something some people are very used to, while it’s unknown territory for others.

Contribution of blood is an estimation of the genetic contribution made to an individual by a specific ancestor. It is given as a percentage. The base theory is that each of the parents contribute half of the genetic makeup for the offspring (50%). Each grandparent contribute a quarter (25%) each, and so on.

For each generation, the total contribution totals 100%. For each generation we go back, any single ancestor’s genetic contribution thus gets less important. A dog 10 generations back contributes less than a tenth of 1% of its genetic material to the present generation.

The contribution of blood should not be interpreted as giving a precisely accurate measure of the genetic contribution in a hound. In these calculations, the whole of generation 10 seems to be as influential as the parents. That’s not how these things work.

Look at the contribution table below, there is a cumulative effect of each generation. Each parents 50% contribution is made up of 25% from each grandparent, which is made up of 12.5% from each great-grandparent, and so on back through the generations.


GenerationContribution pr appearance

How can I use this?

These values are useful to see which dog is more influential in a certain breeding-program. This is especially true if the breeder is linebreeding. Then one of the more interesting questions is “who are you linebreeding on?”. The contribution of blood will give a good answer to this question. Look for the hounds with high percentage in common ancestors.

If a dog’s parent is also a grandparent on the other side of the pedigree then we can see that this ancestor has contributed 75% of the genetic make up of the dog. It’s not so easy to calculate when an individual appears twice in the 4th generation, 3 times in the fifth generation and once in the 6th generation. Or if she appears 12 times in the 8th generation, 8 times in the 9th and 7 times in the tenth. It’s a very handy way to see genetic influence without having to calculate all of this yourself. When we get way back in the pedigree, it’s quite common that certain dogs appear many times in many generations, making it hard to calculate. Now IWDB can tell you how much genetic influence that ancestor has on your own dog.

The popular sire syndrome

There’s been a lot of discussion in the worldwide Irish Wolfhound community on the popular sire syndrome, especially related to Quincy of Kilmara, his parents and siblings.

The popular sire syndrome is usually used to describe the situation where one stud dog and his offspring has become so popular that it’s very hard or impossible to avoid him in any given pedigree or mating. Most or all dogs alive will be related to him in some way. This constitutes a genetic bottleneck, where this dog’s genes are spread throughout the whole worldwide population.

Historic popular sires

There’s been a number of popular sires in Irish Wolfhound history, where some reasonably popular dogs born in the 70s now being in most pedigrees. The most well-known example of these is Eaglescrag Lysander, born in 1975. Almost all dogs born from 1999 and onwards are related to him. The last litter born without him in the pedigree was born in Canada in 2012. Other well known and historic examples are Clonboy of Ouborough and Sanctuary Rory of Kihone who both have a very special place in our breed history as important dogs around World War II. They are both present in the pedigree of every Irish Wolfhound born in the last 50 years or so.

Eaglescrag Lysander
Eaglescrag Lysander, now present in almost every pedigree of Irish Wolfhounds alive today.
The development of Eaglescrag Lysander’s influence on the breed

How do they occur?

The popular sire syndrome occurs when there’s either very few individuals to breed from, or one dog produces excellent progeny who are then used a lot. Not all dogs who produce a lot of litters will become a popular sire and some dogs do eventually become very popular through the quality of their progeny even though they didn’t breed that much.

A good example of this is our 100+ founders, who are all present in all modern Irish Wolfhound pedigrees. It’s thus impossible to breed an Irish Wolfhound without the blood from great danes, borzois, the numerous deerhounds, the one mastiff or one tibetan dog used in resurrecting the breed more than a century ago. They’ve all gone on to become involved in every Irish Wolfhound pedigree. This has occured naturally, mainly through the breed bottlenecks around World War I.

Wolf-tibetan dog
Wolf – the tibetan dog present in every Irish Wolfhound pedigree for almost 100 years

In IWDB.ORG, there’s a special tool (Under the offspring-pane) to look at the influence every dog has had historically. These graphs really show how a popular sire syndrome evolves over time. There seems to be a point-of-no-return where a dog who passes that point eventually will become a popular sire given enough time and generations. One might argue that this really won’t be a problem unless each dog is reasonably closely related to the dog in question. With Sanctuary Rory of Kihone it took only four generations before he was present in the pedigree of more than 90% of dogs being born. Thus he had a major influence because of the short timespan used to become dominant. With Eaglescrag Lysander it took six generations to reach that point. The same goes for Quincy of Kilmara who passed 90% in 2016. Others are slower in gaining influence, like Wild Eagle Saxon-StClair, born in 1980 and now approaching 90% population coverage, nine generations later.

Influence of Sanctuary Rory of Kihone
Sanctuary Rory of Kihone very quickly got a presence in every Irish Wolfhound pedigree

Some mathematics

Some would argue that the popular sire syndrome really doesn’t matter unless the sire in question is present in all 5 or 6 generation pedigrees. The tibetan hound Wolf had his first litter in 1892, some 31 generations ago. Looking at the pure mathematics of this, these 31 generations would include some 4 billion individuals. It’s extremely unlikely that any dog born at that time who had descendants over a few generations wouldn’t be present in all pedigrees today. Even if Wolf is present 4 million times in your 31 generation pedigree, he would still only have contributed 1/10 of a percent of the gene material in your dog. His influence is thus reduced through the many generations passed and the influence of other dogs.

Does it all matter?

Is the popular sire syndrome really important? Yes, it is. As a breed we need to make sure there’s a huge variation in the dogs being used in breeding. If we all use the same sires or allow them to be overused, we will lose genetic variation, be more vulnerable to genetic diseases and generally have a less diverse breed than we do today. It’s the responsibility of every breeder to take care of our breed and make sure we don’t get stuck in genetic bottlenecks. It’s also the responsibility of every owner of males to make sure they don’t become matadors. A matador is a very popular stud dog, generally used to sire more than 5% of the population in any given region. Creating matadors will increase the likelihood of him becoming dominant in pedigrees over a short period of time. Special care should be taken when semen is exported or stud-dogs are being used abroad as these may quickly be influential around the world.

Given the new tool in iwdb, breeders may see how any dog in a trial mating has influenced the breed and take appropriate action as they see fit.

Blog post written by Per Arne Flatberg

All lives matter

All Irish Wolfhound-lives matter. If you’ve ever had an Irish Wolfhound, we encourage you to add lifespan-info to The Irish Wolfhound database at

The database has pedigrees of around 160,000 Irish Wolfhounds. There’s lifespan-information on more than 6,000 of them. That number is rapidly increasing. This information allows new knowledge to be gained about diseases and longevity in Irish Wolfhounds. In addition, it helps breeders make informed choices when selecting breeding stock. We need your help in getting info about your deceased dog in the database. Lifespan info is shown on the pedigrees and there’s also a listing of average lifespan for each dog’s pedigree under the ancestors-pane.

How can I help?

By submitting lifespan-information to, information will be archived and published. The information will also be used to calculate longevity-info in the breed and in pedigrees. In order to get a complete picture, we need information on all dogs, not just those that have been bred from.

There are several ways you may submit info:

  1. Send us an email at or a message on Facebook. We need the dogs name, date of death and cause of death if available. If you don’t have the exact date, we will put in an approximated date if you remember how old it got.
  2. Look up the dog in If you are a registered user, you may add info with Correct/Append to this pedigree. If you’re not, feel free to use the button “Report a problem” to send us the information mentioned above.

Visualising inbreeding

Paying attention to inbreeding levels is important for breeders, breed bodies and buyers.

Kennel Clubs worldwide recommend low inbreeding levels. They want to combat genetic diseases and inbreeding depression in breeds. Recommendations vary a bit. We find the recommendations of The Kennel Club to be quite sensible with some adjustments.
[…]where possible, breeders should produce puppies with an inbreeding coefficient which is at, or below, the annual breed average and ideally as low as possible.
The point being made is that we need to breed below current levels in order to not increase inbreeding in general. We believe a one year perspective might be a little low as it’s vulnerable to fluctuations based on just a few litters, and have chosen to work on the last ten years instead. We also find the idea of just working with national averages a bit outdated, and have chosen to use the whole world for our baseline data.


We struggled a bit on how we could show inbreeding understandably. Could we use a diagram? Maybe a combination of line and bar graphs? Maybe use a table?

Graph showing a sample litter and the level of inbreeding compared to the breed average
We chose to provide a “speedometer” type dial to show levels of inbreeding. If the arrow points to the green area, the inbreeding levels are below average. Yellow is around average values. The red is above average values. The max-value is the highest recorded coefficient of inbreeding in that period. It should thus be quite easy to see if a dog is more or less inbred than the average. We also provide a description, stating what average values are at.

We’ve previously created a handy table on inbreeding in the Irish wolfhound population.

Reading healthchecks

We have added quite a lot of health data to the database. These are public records containing results from screening programs. We are making progress in opening up for user-submitted data, but aren’t quite there yet.

Types of data

Most of the screening results fall into one of four categories:

  • Hips or Hip Dysplasia (HD)
  • Elbows or Elbow Dysplasia (ED)
  • Heart/Cardiac
  • Eyes

In addition there is some data on Patella Luxation (PL), Spondylosis, Thyroid levels, and some other problems, but the bulk of our data fall into one of the top categories.

Hips and Hip Dysplasia

There are numerous ways to annotate data on hip dysplasia. If the result is seen as a single letter, it’s the worst grade of the two hip joints. The scale is as follows:

  • A: No signs of Hip Dysplasia
  • B: Near Normal Hip Joints
  • C: Mild Hip Dysplasia
  • D: Moderate Hip Dysplasia
  • E:  Severe Hip Dysplasia

This scoring-system is used throughout most FCI-countries. However, in the US, Canada, Switzerland, UK, Ireland, Australia and New Zealand other systems are used. The US and Canada use the OFA-scoring mode, whereas the UK, Ireland, Australia and New Zealand use what’s called the BVA/KC-scoring mode. In Germany a more finetuned version of the FCI-system is used. You may read more on these different scoring modes in this excellent article.

For comparision, we’ve put together the following table:

FCIUK, AU, NZSwitzerlandUSA (OFA)
A0-30-2Excellent and Good
B4-83-6Good and Fair
C9-187-12Borderline and mild

In some older screening systems, the grade NR is also recorded, meaning No Remark, which would be similar to A or Excellent.

Elbows and Elbow Dysplasia

For elbows and elbow dysplasia, systems have become much more standardised over the last few years. While Elbow Dysplasia can mean a number of different things, the systems used throughout the world grades elbow dysplasia according to this:

  • Grade 0 = normal elbows (no enthesophyte formation)
  • Grade 1 = Mild ED (<2mm thickness of new bone formation)
  • Grade 2 = Moderate ED or a primary lesion (2mm to <5 mm of new bone)
  • Grade 3 = Severe ED (5+ mm of new bone formation or ununited anconeal process)

Some countries will grade both elbows separately. You will then see scores for each elbow (0/1 for example), while others only list the worst elbow without further information (2 for example). You may occasionally see NR used on older elbow-tests as well. That means No Remark, transforming to grade 0.

The Orthopedic Foundation For Animals has an excellent article on Elbow Dysplasia here  which also explains terms used.

Heart and Cardiac

While there are established systems in place for hips and elbows, the territory for heart problems and the cardiac system is more unclear. First off, there’s numerous ways to examine a canine heart. Most breed bodies recommend a composite check, consisting of ausculation, ElectroCardioGram (ECG) and EchoCardioGram (Cardiac Ultrasound). There are several methods to evaluate these results. There’s some consensus across Europe to use the Vollmar-protocol for evaluating results, except for Great Britain where a separate UK-scheme is used. In the US, the screening results recorded by OFA are more varied, but to our knowledge, full tests are done when results are marked with Cardiologist, Echo.

Most screening programs will use a 3-step grading:

  • Normal
  • Abnormal
  • Equivocal

The Irish Wolfhound Health Group has an excellent article on heart disease in the Irish Wolfhound on their website.


You will know there are a number of eye diseases that can affect a dog. The screening result will display what disease (if any) was found. For checks of type Eyes (CERT) and a result which is a number, the number indicates which year the eyes were certified to be fine. If there are any remarks here, they will explain what was wrong.