Blended Breeds: How New Sheep Breeds Are Born

If you love wool, you’ve probably read about sheep breeds that were developed by crossing other purebred sheep. These are sometimes called composite breeds, and a classic example is the Corriedale with its Lincoln and Merino ancestors. Now that the Corriedale breed has been with us for about a century, how is it different from a Lincoln/Merino cross? Is a composite breed different than a crossbred?

Handspinners often come across fleeces and fibers that are clearly marked as crossbred. A fleece from what we often call a spinner’s flock might have a half-dozen breeds listed on the label, or it might be as elusive as “Merino X.” These first-generation crosses produce a wide variety of results; some offspring look a lot like one parent, some like the other parent, and some offspring will be a more equal blend of the two parents.

Billy the Crossbred Ram (gray lock at right) is a first-generation cross between Border Leicester (left) and Cormo (center). Billy has a unique fleece that blends the wool character of his parents and makes handsome lace.

For example, Billy the Crossbred had Border Leicester and Cormo parents. Billy is a nice mix of the two breeds—shorter and finer than Border Leicester, but much more lustrous than Cormo. However, Billy could have had siblings that ranged from very Border Leicester to very Cormo-like. They could have had different fleece characters, the sheep could have grown and matured at different rates, and they might even have had very different personalities. All this variation can make large-flock management difficult.

Now-familiar sheep breeds such as Corriedale, Columbia, Cormo, and Targhee were all developed like Billy—by crossing finewool and longwool sheep. To reduce the variation within a flock, a crossbred like Billy would have been mated with similar crossbred ewes. Their offspring would go on in a similar fashion until a breed is established: two sheep that look the same have lambs that look like their parents. During this process, something new and interesting is formed. Based on the shepherd or researcher’s choices, certain characteristics are saved, while others might be lost.

Columbia fleece? Yes, please! Read Kate's article about Columbia sheep and wool in the Summer 2017 issue of Spin Off.

The result after decades of hard work: a Corriedale isn’t the same as a Lincoln/Merino cross. Now, more than a century after developing the Corriedale, flocks around the world have evolved in different ways: an American Corriedale is different than a New Zealand Corriedale. And the work continues; as Canadian researchers noted in Canadian Journal of Animal Science, “Today, as many as 418 sheep breeds that have been documented in nearly 75 countries are combinations of two or more distinct breeds, populations, and landraces that have records on pedigree and morphological characteristics . . .” (“Development of composite sheep breeds in the world: A review.” D. P. Rasali et al, 2006).

What are we to do with all this variety? Spin it all!

Join me at Interweave Yarn Fest 2018 for my Blended Breeds workshop. We will spin a wide variety of composite breeds, their parent breeds, and create reference materials to help you track these woolly family trees.

—Kate

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