Fleece color and spotting

Because a big part of our income comes from fleece, we are always trying to improve the wool that our sheep carry. I’ve often said that you can’t produce great fleece from unhappy sheep, but producing high-end fiber is so much more than that. The more I studied about the wool that our sheep produce, the more I realized is involved; from crimp and structure, to handle or feel, and from length to color, both genetics and environment go into producing what we end up “harvesting” from our sheep once each year. Today, I thought we’d look into color a bit.

The experts tell us (and believe it or not, there are sheep color genetics “experts”!) that the ultimate color of wool that a sheep produces is essentially based in four different genetic locations. These locations control whether the wool comes in the white to gray to black spectrum or the ivory to tan to brown spectrum, how dark or light the wool is within that spectrum, whether it has any blobs of white (known as spotting – spots are always white in sheep!), and whether there are color variations or whether it is one solid color across the entire sheep. With these four different controls, literally hundreds of possibilities exist for a final product.

As I dug into the genetics in the early years of our flock (beginning in about 2002), I began to realize how very much control I had, simply by understanding the genetics of color. Through observation and recording, I began to figure out the genetics of each of our breeding sheep, knowing that if I had that information, I could put pairs together to produce an incredible variety of naturally colored wool for our customers. When this finally really sunk in, I also came to realize that with this kind of control, I could purposely put together certain sheep in my breeding groups to produce lambs that were very rare or unusual. The more I understood, the more I realized that there was still much to understand, and eventually, I began to do some of this research here at our farm. Curiosity began to lead me down a path that I would never have otherwise considered – and what a ride it has been!

One of the things I have been working on recently – and that has sometimes become so involved that I have, at times, forgotten to post a blog until the last minute (or not, like this one that was supposed to post yesterday! Oops!) – is the inheritance of spotting from generation to generation. I find that many spinners like some spotting in their fleeces, and others don’t. For this reason, I began trying to understand how to produce “just the right amount” of spotting in some of our lambs, while producing others in the same year that are unspotted. Honestly, a little spotting goes a long way!

The experts have told us that spotting is a very simple genetic location called S with only two possibilities: either spotting or no spotting. Like most other traits, every sheep gets two copies of this gene, one from sire and one from dam. If they get one copy of spotting, say the experts, then they will have a spot on the top of their head and the tip of their tail. If they have two copies (one from each parent), then they have lots more spotting. That’s all they had to offer us in their wisdom, and who was I to argue? I did read in one very early study that if you bred two very spotted sheep together, then the lamb would be even more spotted – and theoretically, you could keep doing this until you got a fully white sheep that was essentially one huge spot, but most people ignored this whole idea. After all, if you want a white sheep, you can easily get this by using the white gene at another location.

Yet, this whole idea of more spotting stuck with me because if there was only one location involved and it was so simple, then it wouldn’t explain how you could keep getting more and more spotting. The only thing that would allow that to work was if another location was involved that determined exactly how much you would get if you had two copies of spotting at S. Along the way, I decided to get rid of spotting in about half of my sheep for those purists who like their wool one color, and to allow for random spotting in the other half of the Romeldale flock for those who liked a bit of white contrast within their fleeces.

Our current breeding ram, Nahe, at one day of age – notice the white spotting on his face between the eyes, on the top of the head, on the back of the ears, and on the sides of his body – even though he only carries one copy of spotting at S. All of these spots have been recorded in my new spotting inventory.

The issue, however, is that in recent years, I have found myself getting some exceptionally spotted lambs, even when it was obvious that either sire or dam didn’t carry any spotting at all. If one didn’t carry spotting, then the lamb could only possibly have inherited one copy from the spotted parent – and one copy was supposed to be only the top of head and tip of tail. Something was amiss here – it didn’t make sense. And that’s how I ended up down the rabbit hole that is my spotting inventory.

For the past few weeks, I’ve been deep into investigating the genetics of spotting. As my data source, I decided to take a close look at many of  the Romeldale lambs that we have produced since 2008, and see where they carried spots and also figure out based on their parents whether they carried one copy of spotting at S or two. The reason I could do this is because since 2008, we’ve been photographing each and every lamb born here on the farm from various angles. Those lambs from 2008 usually only have two photos – I wasn’t nearly as good at that point about getting every view, but each year, I got better. By 2010, I was getting pretty much every angle of the lamb, and all of these photos are organized by year and then alphabetically by the name of the lamb. When I started this project, I went through well over 1500 photos and have cataloged about 250 of our lambs in my database. What I have learned so far – and I am far from finished – is mind-boggling! More about this on Friday.

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  • Janice says:

    Very interesting! I look forward to more. Nahe is lovely. Was the tip of his tail white? Need I say that I like spotting?

    • Dee says:

      I just finished tomorrow’s blog that includes lots of spotted lamb photos for your pleasure! Yes, Nahe did have a white tip on his tail – which I am finding is the basis for any spotting. If they have spotting, they generally have this top of head and tip of tail spotting.

    • Dee says:

      Yeah, but I try really hard to keep my blog to under 1000 words, and I was already over that. As a result, I thought I’d finish up tomorrow with the rest of what I now know – but there will likely also be future updates as I figure this whole mess out. I’ve got a lot of new info – I’m just still not quite sure how to tease out all of the answers. I keep telling myself that every step forward is one step towards the goal of total understanding of how spotting works. I am a bit impatient, though!

  • Jane M says:

    How do I say …. You stopped right in the middle of the most interesting part!!!

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