Sparks Breeding Programme
general information on using Kinship tables
The Shire Horse Society (‘the Society’) has adopted SPARKS from 2023 to tackle inbreeding in the Shire horse population. This is needed because inbreeding leads to loss of genetic diversity in the population, which, in turn, 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 specific mare/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 who:
- is pure-bred and registered in the breeding section of the Studbook, and
- was born in or after 2003, up to and including 2021
Each Kinship Table is specific to an individual mare who is named on each page (three pages per mare) together with her 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 names pure-bred Shire stallions with a Shire Horse Society Service Book in the UK in 2022, together with each stallion’s Studbook number, colour, Inbreeding Coefficient, Mean Kinship coefficient, Kinship Band, availability for AI and location. Note: the locations are not guaranteed – some stallions may be in a different location for the next breeding season.
The Table also gives 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 whereas those of 0.05 and above are not.
How are Kniship Tables used?
The Kinship Tables are published on the Society’s website and can be downloaded free of charge. SPARKS – The Shire Horse Society (shire-horse.org.uk)
Use of the Tables 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, and breeders should continue to use their own best judgement in this regard. The Tables are an additional tool to add genetic health to dam/sire pairing decisions.
To facilitate help with interpretation of the Kinship Tables, the potential matings between mares and stallions are ranked into four Tiers in every Table. Tier 1 represents the best genetic pairings, and Tier 4 the worst. These are colour coded as follows:
Download Sparks Kinship Tables and guidance notes below...