Explaining Effective Population

Genetic diversity is an important component of biological diversity.  Rare and native breeds of farm animals and equines are part of our cultural heritage often associated with the type of traditional land management that is required to conserve important habitats.   The breeds themselves have genetic traits that will be of value in the future, and it is crucial that we do not lose them.

The genetic diversity of a breed is assessed by its effective population size which is based on the total number of animals in a population and the relative numbers of sires and dams.  A low effective population size signifies a greater likelihood of inbreeding and subsequent loss of genetic diversity.  For an equine breed to survive it is generally accepted that you need to have an effective population of 100 or more.

The Eriskay pony is the most critically endangered equine breed on the DEFRA lists with an effective population that has shrinking and now has reached critical level.  The DEFRA figures show this decline over the years.

Perhaps a more positive way of looking at things is to consider the number of ponies in the potential breeding population.  Our stud book records show that the total population is 408, of which 66 are over 30 years old.  However, within these numbers are 33 ponies who have an unknown owner as the new keeper has not updated the passport as legally obliged to do.

Within this potential breeding population there are 95 mares who are 20 or under and 18 entire stallions. 

In the last 5 years, just 20 Mares produced 29 foals using different 9 stallions.  This is significantly less than was being produced in previous years and is an area of great concern.   As part of the toolkit breeders use to inform breeding choices, Eriskay owners can access SPARKS which is a computer database that works with a genetic analysis programme called GENES to help breeders sustain and strengthen small populations.  If used correctly, and appropriately, this will help maintain a healthy herd and slow down the loss of genetic material.   

The Eriskay Pony Society has always encouraged owners to consider breeding and each year we forward the list of licenced stallions to mare owners and a list of mares to owners of licenced stallions.  If every healthy youngster could produce 1 or 2 foals over a lifetime, this would go a long way to help in saving the breed and will restrict the loss of diversity.

Some stallions, owned by EPS or with the support of their owners, can be loaned allowing them to visit the mare and run with her at her home.  In other cases, the mare can visit and run with him at the stallion’s home or at a breeding centre.  For those mares living at livery, we may even be able to offer the possibility of a loaner taking the mare and foal through to weaning and deliver her back to her owner with or without plus one at foot.  

Artificial Insemination and other types of assisted breeding are commonly used with many breeds and although it has been attempted with a small number of Eriskays, it has not yet resulted in a foal being born.  The techniques for collecting and storing good viable semen is improving all the time and we very much hope that we will soon have a successful outcome.  Would you like to be the first to succeed?

KEY POINTS.

  • The future of the Eriskay Pony is in your hands.
  • The situation is now critical.
  • Can you breed from your mare?
  • Help and support is available.
  • Have you updated the Registrar with any changes to the information on your pony’s passport.

By Lorna Holden. Registrar (registrar@eriskaypony.org)

EPS Autumn Meeting

Doonies Rare Breeds Farm to close.

It has recently been announced that the RBST approved Doonies Rare Breeds Farm in Aberdeen is to close after 30 years.  The farm, which is one of only 2 such approved farms in Scotland has fallen victim to the regeneration and expansion of Aberdeen South harbour and the land is intended to be used for an energy transition zone.

Aberdeen City Council, who own the land and buildings and did not want to renew the lease, have agreed with Graham and Debbie Lennox that the lease will be terminated later this year which means this incredibly popular attraction will shut down in August with all the stock either sold or moved on to new breeders.

The farm was originally operated by the City Council, with Graham as manager, but was due to be closed in 2008 as a cost cutting exercise.  After negotiations, and a lengthy public campaign to save the farm, Graham and his family took on the lease along with the livestock and, from 2010, ran it as a visitor and educational attraction increasing visitor numbers by 50%.

Generations of children from local school groups, families and tourists have visited the farm to see the rare and native breeds on display, hear all about the role they played and continue to play, in Scotland’s agriculture and landscape and to learn where their food comes from.

The farm is home to a famed herd of English Longhorn cattle as well as numerous breeds of sheep, pigs, poultry, Clydesdale horses and, of course, Eriskay ponies.

Under the Doonies, and latterly Altens, prefix, the Lennox family bred a lot of Eriskay ponies with their foundation stallion, Auchenbrook Ptarmigan, and mares Misty and Rhona, contributing greatly to the overall population of this native pony which remains a Priority breed for the RBST.

On a personal note, my wife bought our first Eriskay, Doonies Brogach, from Graham in 2005 to be followed in 2014 by Altens Alice.  This started our interest in the breed and since then we have gone on to breed two of our own ponies from Altens Alice, using the EPS owned stallion Whitney Harrier.  We also have a young stallion, grandson of Ptarmigan, and it is reassuring to know that the bloodlines established by Graham at Doonies will continue.

The Eriskay Pony Society is incredibly saddened to hear about the Doonies story coming to an end and we want to extend our grateful thanks to Graham, Debbie, and their family for what they have done over the years for Eriskay ponies as well as many other rare and native breeds and we wish them all the best for the future.

Steve McMinn, Chair, Eriskay Pony Society.