Leader sheep in Iceland. Photo taken by Ragnar Thorsteinsson.
The Icelandic leader sheep has been known to exist in Iceland ever since the settlement of the country over 1100 years ago. The Icelandic leader sheep is considered as a subpopulation within the Icelandic sheep. In the middle of the 20th century the population experienced a major bottleneck due to a disease eradication programme.
Standardized trials have shown that the willingness of purebred leader sheep to walk or run ahead of “ordinary sheep” is unequivocal. In 2008, a total of 1422 individuals of leader sheep were identified and recorded. Majority, 83.7 %, were ewes, and 7.5 % and 8.8 % were rams and wethers, respectively. Out of the 415 flocks having leader sheep, 60% had only one or two leader sheep individuals. The maximum number was 20 leader sheep in a single flock.
The population is unevenly distributed over the country. Westfjords, as well as the Southeast part of Iceland have very few leader sheep. The nucleus of the breeding stock is on the Northeast corner of Iceland. The basic coat colors of leader sheep are black and grey. Inbreeding in the leader sheep has been successfully controlled during the last few decades; inbreeding coefficient of individuals having sufficient pedigree pedigree data is 2.7 %.
The leader sheep population is an example of a subpopulation of a sheep breed successfully conserved. A proposal is put forward to classify the leader sheep as a separate breed.
This a short summary of an article (on Icelandic) published in Náttúrufræðingurinn (2015, 85 (3-4), 97-115) by Jón Viðar Jónmundsson, Lárus G. Birgisson, Sigríður Jóhannesdóttir, Emma Eyþórsdóttir, Þorvaldur Kristjánsson and Ólafur R. Dýrmundsson.