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Conservation Breeding in British Soay Sheep

Keeping British Soay sheep involves conservation breeding practices as a way to protect the genetic diversity within this sheep and keep its direct link to the past unbroken.  Practices that include breeding for particular characteristics can cause Soay to lose some of its distinctiveness, adaptability, and utility.  Each time there is human interaction with breeding, it increases the evolutionary process within the sheep.  When humans decide which sheep to breed, which sheep to castrate, we are unknowingly limiting the genetic influences.103

Luckily, Soay sheep genes are very diverse and somewhat forgiving our ‘interference’.   As a feral population, the primitive Soay remained isolated for thousands of years, and may actually be considered to be an intermediate between a breed and a subspecies.  In the UK, Soay are on the Rare Breeds Survival Trust (RBST) At Risk Watch list to protect this small population of sheep.  Current conservation efforts in North America are focused on increasing this small population of RBST Soay sheep that were brought to this continent.

Increasing the British Soay population is needed to ensure their survival in North American, however we need to breed them responsibly.  Breeding for color, horn shape or other specific traits narrows the genetic diversity and risks losing some of the variants, such as disease resistance, seen in the wild.

Modern sheep conformation that produces consistent breed characteristics took hundreds of years, if not thousands to form. Soay sheep have not been ‘improved’ which explains why they have such wide genetic diversity and produce such a variety of characteristics.  These differences can be seen in their wool color and texture, differences in size and horn shape and temperament. This variety attests to the genetic diversity that still exists within Soay sheep. Most modern breeds have been so selectively bred they no longer have the genetics that makes them adaptable to changes in the environment.  They have lost their resistance to diseases that the primitive (unimproved) Soay have not.   For example, a disease that might affect one Soay out of many Soay, could devastate an entire flock of a modern breed because their genetics are so narrow that they would all lack the same resistance to a particular pathogen.

105 Soay sheep are fortunate, in that they have remained ‘unimproved’ (not selectively bred) for thousands of years.  The conservation of British Soay sheep does not involve conformity to a breed standard.  Its pedigree can only include British Soay registered with the RBST so that their lineage can be traced back to St. Kilda.  The conservation of Soay sheep is primarily the responsibility of the owners to ensure that they are registered with the Rare Breeds Survival Trust in the UK.  This is the only organization that can authenticate the pedigree. 
Human involvement with any breed increases the evolutionary process and potentially shapes the breeds characteristics.  Knowing this, we can make informed choices that protect the diversity that exists within the breed and limit the impact that our breeding choices make on the future generation of Soay Sheep.