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Please Note: the Kinship Tables in the right hand panel include mares and stallions in the UK and EIRE.


The Shire Horse Society (‘the Society’) has adopted SPARKS to tackle inbreeding in the Shire horse population. This is needed because inbreeding leads to loss of genetic diversity in the population. In turn, this threatens the health of individual horses and the health and sustainability of the Shire breed as a whole, because it has the following consequences:

  • increased infertility
  • increased foal mortality (deaths)
  • increased likelihood of harmful genes accumulating in the breed
  • increases risk of inherited diseases and deformities
  • reduced overall fitness of the breed and resistance to diseases

A powerful way of tackling inbreeding is by managing ‘Mean Kinship’ through selection of mare/stallion pairings.

What is Sparks?

SPARKS is an advisory scheme that helps manage Mean Kinship and inbreeding. It is a computer programme that calculates Mean Kinships for every living pure-bred Shire in the Studbook, measuring how related any one Shire is to all others. SPARKS also calculates the potential inbreeding of foals resulting from specificmare/stallion pairings. Based on this analysis, SPARKS produces Kinship Tables for mares.

What are Kinship Tables?

The Kinship Tables are a tool to help breeders manage Mean Kinship and inbreeding via their decisions on which stallions to put to which mares. There is a Kinship Table for every living Shire mare in the UK and EIRE who:

  • is pure-bred and registered in the breeding section of the Studbook, and
  • was born in or after 2004, up to and including 2022

Each Kinship Table is specific to a named mare. Note, each Table has more than one page. Each one gives the mare’s date of birth, Studbook number and Mean Kinship coefficient. Based on the Mean Kinship coefficient, the mare is assigned to a Mean Kinship Band. Mares in Band A are of lowest Mean Kinship, i.e. are least related to the rest of the population, and those in Band H are the most related.

The mare information also gives the mare’s Inbreeding Coefficient. This is a measure of how related an individual animal is to itself through common ancestors that appear on both sides of its pedigree, whether in recent or distant generations.

Each Kinship Table includes a list of pure-bred Shire stallions in the UK and EIRE that have a Service Book for 2024. For each stallion, there is information on their colour, kinship figures, whether available for AI and location. Mare owners - check whether the stallion you select for mating with your mare in 2024 has his Service Book for 2024 before mating. This is a mare owner responsibility. If he has not got his 2024 Service Book, the Society will not be able to register the progeny in the breeding section of the Stud Book.

The Kinship Tables include stallions that are deceased or overseas for which frozen semen is available in the UK. This information is provided to help with a broad range of breeding choices.

How are Kniship Tables used?

The Kinship Tables give the ‘Co-ancestry Coefficient of Progeny’ for each stallion/mare pairing. This is the level of inbreeding that the resulting foal would have. The lower this coefficient, the less inbred the foal would be. Co-ancestry coefficients of below 0.05 are considered acceptable. Those at 0.05 and above are not.

The Kinship Tables are opposite for download free of charge. 

Using SPARKS is voluntary and intended to help mare owners to select a stallion. The Tables do not relate to the physical attributes of any mares, stallions or potential foals. Breeders should continue to use their own best judgement on this. The Tables are an additional tool to add genetic health to dam/sire pairing decisions.

To help interpretation of the Kinship Tables, the potential matings between mares and stallions are ranke into four Tiers. Tier 1 represents the best genetic pairings, and Tier 4 the worst. The Tiers are “traffic light” colour coded as follows:

Kinship Tables

Download Sparks Kinship Tables and  guidance notes below...

 Sparks A

 Sparks B

 Sparks C

 Sparks D-E

 Sparks F-G

 Sparks H

 Sparks I-L

 Sparks M-N

 Sparks O-R

 Sparks S

 Sparks T

 Sparks U-Z

 Guidance Notes

Note for researchers. The data provided in the Kinship Tables are highly filtered from the SPARKS database and should not be taken as an accurate representation of the current Shire horse population. As such they are not suitable for research purposes.


Tier 1

The mare and stallion are from the same or an adjacent Kinship Band AND the mating would produce a foal of lower co-ancestry coefficient than the Mean Kinship of the Mare. These matings are said to be ‘SPARKS compliant’ and are coloured green in the Kinship Tables. THESE MATINGS ARE ENCOURAGED.

Tier 2

The mare and stallion are from the same or an adjacent Kinship Band BUT the mating would result in a foal of higher co-ancestry coefficient than the Mean Kinship of the mare but still less than 0.05. These matings represent ‘The Best of the Rest’ and are coloured yellow in the Kinship Tables. THESE MATINGS ARE THE PREFERRED ALTERNATIVE IF A SPARKS COMPLIANT OR ‘GREEN’ MATING DOES NOT EXIST OR IS NOT DESIRABLE.     

Tier 3

The mare and stallion are from widely differing Kinship Bands and Kinship Coefficients less than 0.05. These matings bring together genes in a way that puts less common genes at greater risk of loss. They are coloured orange in the Kinship Tables and ARE DISCOURAGED. 

​Tier 4

These matings, coloured red in the Kinship Tables, are highly inbred and increase the probability of deleterious genes/harmful traits being expressed in future generations as well as accelerating the loss of genetic diversity. THESE MATINGS SHOULD BE AVOIDED.



Please note:

  • The Tiers are an assessment of the merit of pairing of two horses. They are not an endorsement or criticism of the genetic makeup or physical characteristics of either horse.
  • The traffic light colours are shown on the names of the stallions, but do not represent the level of inbreeding of the stallions themselves. They represent the level of inbreeding that the foal would have if the stallion was mated with the named mare.
  • For red matings, the red traffic light colour is highlighted on the Co-Ancestry Coefficient of Progeny figure as well as on the stallion’s name. This is to help distinguish between orange and red matings, given that the two colours may look similar on some computer screens.

Important notes on using Kinship Tables

Kinship Tables are valid for one year only because the Shire horse population, and therefore the kinship relationships within it, change each year. The Tables are therefore updated every year. The year they are valid for is shown at the top of each one. Please use the correct Tables for the year concerned.

The 2024 Kinship Tables include mares born in or after 2004. Tables for mares born before 2004 are available on request from the Society office, quoting the mare’s name and Studbook number. Please note that it may take over a week for the table to be produced and sent to you.

For information on which stallions are in the Kinship Tables, see the section “What are Kinship Tables” above.

Contact details for stallion owners are in the “Alphabetical list of UK stallions issued with a service book in 2024” document available to download here or on request from the office

How to find a mare in Kinship Tables

The Kinship Tables are produced as ‘pdf’ electronic documents, in alphabetical groups by prefix. The pdfs for each group can be downloaded from the Society’s website. To find the Kinship Table for any mare:

a. On the Society website, go to the “SPARKS Breeding” tab and select “SPARKS Breeding UK & EIRE” from the drop-down menu Shire Horse Society of Great Britain | Sparks Breeding Programme (
b. Select the download link for the alphabetical group that includes the first letter of the mare’s prefix
c. Download the pdf from the link
d. You can now search the pdf for the mare. You can do this by scrolling through the pdf, but it may be easier to search as follows:

Hold down the Ctrl key press the F key. You will see a search box has opened at the top of the page. Release both keys. Type the mare’s stud book number, or her prefix and name, into the search box. The pdf should jump to the Kinship Table for that mare. Because stud book numbers are unique to individual horses, this may be the most efficient way to search. The pdf may jump to part-way through the Kinship Table you are interested in. You will need to scroll up to get to the top of the Table.

For help on downloading and using the Tables, or finding mares in them, please contact the office.

Financial Support

The Society provides SPARKS Foal Grants to encourage Tier 1 Green and Tier 2 Yellow matings. The Grants are payable to mare owners who are members of the Society on successful registration with the Society of a pure-bred Shire foal from a Green or Yellow mating, whether by natural service or AI. The Grants are:

Green matings at least £200       Yellow matings at least £100

Each year, there is a fund for payment of the grants. The amounts above are guaranteed. Any residual funds will be shared between the qualifying mare owners.

There are no payments for Orange or Red matings.

Correction and Anomolies

The information in the Kinship Tables is only as good as the information in the Society’s Studbook, so the more up to date the Studbook, the better. Therefore, if you see a mare in the Kinship Tables that you know has died or been exported, please notify the Society office, sending in the passport if you have it. Likewise, if you see information that is not or might not be correct about any horse, please let the office know.

Contact Details and Help

Shire Horse Society, The Old Dairy, Rockingham Castle, Market Harborough, Leicestershire, LE16 8TH

T: 01536 771611 E:

Notes for researchers. The data provided in the Kinship tables are highly filtered from the SPARKS database and should not be taken as an accurate representation of the current Shire horse population. As such, they are not suitable for research purposes.

SPARKS is endorsed by the UK’s Rare Breeds Survival Trust

Rare Breeds Survial trust





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