Background
In the late 19th century large numbers of Icelandic sheep, mainly adult wethers for fattening and slaughter, were shipped to Britain. However, it was not until 1979 and again in 1990 that Icelandic breeding sheep were exported from Iceland to Britain. All of them were from a few flocks in Southeastern Iceland. A few Icelandic sheep imported to England from Denmark in 1989 were of the same origin. Thus, the present population of Icelandic sheep in Britain originated from a total of 63 lambs from 7 flocks only and has a fairly local and somewhat narrow genetic base. They were, however, genetically diverse, such as in colour patterns and conformation, although neither leadersheep nor sheep with four horns were included in this population.
Today Icelanders can classify their 460,000 winter-fed sheep into three groups:
- The main population on which meat production is based
- A small population of grey pelt sheep
- The small leadersheep population, recognised as a breed of its own since 2017.
Meat sheep – the most numerous population
When the main group of Icelandic sheep was exported to Britain in 1990 great changes were taking place in breeding work and carcass classification in Iceland. Ultrasonic scanning of muscle and back-fat thickness became an important tool in genetic selection nationwide by 1990 and the EUROP carcass classification system was introduced in all abattoirs in the country in 1998. This, combined with the well established individual recording and data processing system FJÁRVÍS, the application of BLUP breed evaluation and the AI services available to all sheep farmers, has accelerated the progress of selection. This applies to ewe prolificacy, lamb growth rate and carcass characteristics. Thus muscularity is becoming greater. Although just over 50% of the lambs go into the R-class there is a clear trend towards E- and U-classes. Thus comparing abattoir data from 2005 and 2015, E-class grew from 1% to 3% and U-class from 17% to 29%. Fat class results show a clear trend towards leaner carcasses.
There is no evidence of any changes in colour diversity and it is noteworthy that more coloured rams of high breeding merit are coming into the AI services. This was not common 30-40 years ago. Wool and pelts are by-products and their quality traits do not seem to be negatively affected by the accelerated selection for meat characteristics. The sheep are still genetically diverse, hardy, robust and grassland-based. The special breeding line of grey pelt sheep will be addressed below.
Comparing the meatier sheep today to their ancestors at the time when Icelandic breeding sheep were exported to Britain 30-40 years ago show considerable differences, most notably in conformation, particularly in the muscularity of the back and the hindquarters (loin, legs). Rams selected from this population might now even be used as terminal sires in the British stratification system.
The Icelandic sheep in the USA and Canada, also exported in 1990, had basically the same origin as the British exports. Many of the flock owners in North America have since the turn of the century used semen from the Icelandic Southram AI services with good results. As would be expected the main changes there have been in conformation and carcass characteristics. Some of these breeders are establishing small populations of leadersheep by upgrading. Even four-horned sheep are found there, also due to semen imports.
Grey pelt sheep
Since around 1980 the selection of grey sheep with certain pelt characteristics has been ongoing in a few flocks in Southeastern Iceland, basically on the same lines as the breeding of Gotland sheep in Sweden, also a North European short-tail.
Considerable progress has been made in breeding Icelandic grey pelt sheep in recent years highlighting again the great genetic diversity of Icelandic sheep. Semen from such rams, all polled, has been available from Southram since 2013 and flocks in other parts of the country are selecting and fixing certain pelt characteristics in their flocks within a special breeding programme. Emphasis is placed on a more uniform shape and form of wool fibres, namely by reducing the amount of fine undercoat fibres (thel) so as to increase the proportion of long fibres (tog). Thus the bulk of the fleece consists of long and curly hairs. The curled hairs have to be strong, of the right size and reach completely down to the surface of the skin. The commercial value of these grey pelts, and of the wool too, is growing but meat is still the main product. However, the pelt rams have poorer conformation than the modern meaty rams and are in fact similar to rams generally found in Iceland 30-40 years ago. Thus they resemble the rams exported to Britain in 1979 and 1990.
Leadersheep
The Icelandic leadersheep, a unique strain of Icelandic sheep, from 2017 referred to as a special breed, are known for their genetically based behavioural characteristics of leading the flock when driven. They differ substantially in body conformation and several physical attributes from other Icelandic sheep which have been selected primarily for meat characteristics and to a lesser extent for wool and pelt traits. The leadersheep have longer legs, they are slender and high at the withers and their muscles are thinner and there is less fat in the body. Their body weight is lower than that of other Icelandic sheep but their prolificacy is similar. Lamb carcass weights are lower and most of the carcasses go into the O-and P-classes. Purebred leadersheep are only found in in Iceland but as mentioned above some owners of Icelandic sheep in the USA and Canada are through upgrading with imported semen establishing lines now approaching a purebred status.
There was one 50% leaderewe in the group flown to Canada in 1990 and she showed distinct leader characteristics through her lifetime. In Iceland it is generally recommended that only purebred leadersheep should be kept unless an upgrading programme is taking place, often through AI.
Further exports overseas
Since some owners of Icelandic sheep in Britain may be considering imports in years to come, even in the near future, it should be kept in mind that Iceland is free from many animal diseases. These include foot-rot, liver-fluke and Brucella diseases. Maedi-visna was eradicated in the 1960s and good progress is being made in eradicating scrapie. The foot-and-mouth disease has never plagued Iceland. Exports are only allowed from the four districts in the country which have always been free from scrapie. It is noteworthy that exports of live sheep, fertilised ova and semen from Iceland have never brought any infectious diseases into any importing countries.
In terms of bio-security the safest method is importing fertilised ova, semen coming close, but risks are higher when live animals are imported. On the other hand, the very high cost of transferring genetic material by fertilised ova makes semen imports more feasible, followed by imports of live animals. However, the purpose of importing the genetic material may influence the economics of such decisions. Although at least some breeders of Icelandic sheep in Britain are doing their best to maintain certain, accurately recorded, purebred lines with controlled matings, it is inevitable that close inbreeding will cause problems sooner or later.
Useful references
- Jill Tyrer and Ólafur R. Dýrmundsson (2018). Icelandic sheep in Britain. INTERNORDEN 34th Meeting, Radisson Blu Hotel Saga, Reykjavík, Iceland, 21-24 August. Mimeogreph, including appendices 18 pp.
- Ólafur R. Dýrmundsson (2002). Leadersheep: the unique strain of Icelandic sheep. AGRI, Animal Genetic Resources Information, 32, 45-48.
- Ólafur R. Dýrmundsson (2014). The colourful sheep of Iceland – where the farming community maintains biodiversity. In : Toit, D.D. (Ed.),Timeless Coloured Sheep (pp.18-23). Petersberg, Germany: Michael Imhof Verlag.
- Ólafur R. Dýrmundsson and Roman Niznikowski (2010). North European short-tailed breeds of sheep: a review. Animal, 4, 1275-1282.
- Icelandic Leadersheep Documentary: Part 1 and Part 2
*The views in this article are those of the author, Ólafur R. Dýrmundsson, not ISBOBI.