GUIDANCE NOTES ON THE USE OF SPARKS KINSHIP TABLES
1. INTRODUCTION
The Highland Pony Society (‘the Society’) is adopting SPARKS to raise awareness and address inbreeding in the Highland Pony 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 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 doing this is by managing ‘Mean Kinship’ through selection of mare/stallion pairings.
2. 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 Highland Pony on the Highland Pony Grassroots Database, measuring how related any one pony 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.
3. HOW ARE KINSHIP 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.
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 ranked into four Tiers. Tier 1 represents the genetic pairings that are encouraged while Tier 4 matings are those that should be avoided because of potential impact on the genetic health of the whole population.
The Tiers are “traffic light” colour coded as follows:
TIER 1 (GREEN): 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’. THESE MATINGS ARE ENCOURAGED.
TIER 2 (YELLOW): 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 0.1. These matings represent ‘The Best of the Rest’. THESE MATINGS ARE THE PREFERRED ALTERNATIVE IF A SPARKS COMPLIANT MATING DOES NOT EXIST.
TIER 3 (ORANGE): The mare and stallion are from widely differing Kinship Bands and Kinship Coefficients less than 0.1. These matings bring together genes in a way that puts less common genes at greater risk of loss. THESE MATINGS ARE DISCOURAGED.
TIER 4 (RED): These matings are highly inbred (resultant foal with a coefficient of 0.1 or above) 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.
4. IMPORTANT NOTES ON USING THE KINSHIP TABLES
Kinship Tables are valid for one year only because the Highland Pony population, and therefore the kinship relationships within it, changes each year. Tables are therefore only valid for the year in which they are produced. New tables are produced each year.
5. CORRECTIONS AND ANOMALIES
The information in the Kinship Tables is only as good as the information in the Society’s Database (Grassroots), so the more up to date we can get Grassroots, the better the SPARKS data will be.
6. CONTACT DETAILS AND HELP
Mrs S Keron, Secretary
Garbh Allt House
Maidenplain Place
Aberuthven
Perthshire PH3 1EL
Tel: 01764 664000
Email: members@highlandponysociety.com
SPARKS Q&A
Q: Where a Sire or Dam have common parentage how far back in the pedigree would you need to go before it would no longer be considered inbreeding?
A: Where does line breeding stop and when does it become inbreeding – probably at about second cousin level i.e. 0.0625. We have set the SPARKS red line at 0.10 or 10% for the Highland Pony.
Q: What if my pony is “Red”?
A: If foals are red that is not a problem – just more important that if they go on to breed themselves to try to avoid future red matings – i.e. break the chain. Foals that are the product of a red mating are not inferior or any less valuable than those of a green mating.