Saturday, July 21, 2007

Iset

For a while now I've been wondering what exactly is Iset: Is it "age greying" that happens over time? (apparently) Is it a pattern? (doubtful) Can it be mistaken for a modified color?(possibly) Is it a marking? (who knows?) Is is something that can be identified at birth or within the first few months like Ag and Mioget? (hmmm. I wonder?)
That is the question I want answered. I have a theory. I can't prove it or disprove it yet. That will take time. And honestly, I don't care what gets proved. I would just like to understand Iset better.
My theory: Iset is a pattern. Like Katmoget and Gulmoget are patterns that are, visually, the "opposite" of each other. So Iset is the "opposite" pattern of Ag Grey. Ag lightens the undercoat fibers, leaving the fewer outer coat fibers dark in the fleece. Iset lightens the longer outer coat fibers and leaves the undercoat it's original color. It will be visible if a sheep is heterozygous for the gene. It could possibly be even more visible if a sheep is homozygous for the gene. Iset will not be visible if the pattern for it is not present in the sheep's genes. It is like Ag.
And the big buzzer goes.....EEEEEHHNNKK!
Oh, well. The best part about putting forward a theory is that there are usually people that want to disprove it. And that's OK with me. If other folks have some hard-core facts to contribute to my understanding of Iset, I'll be happy to give them thorough consideration and adjust my theory. I don't want to be chastised for trying to use my own brain. But I do hope that I am open-minded enough to welcome other flock owners' detailed observations. After all, I'm trying to satisfy my curiosity about Iset rather than trying to make headlines or waves.
I do have a bit of Iset in my own flock to work with: two adult ewes, and four of their lambs to keep an eye on. Two of those lambs are already first shear yearlings. The other two are babies. I also have one ram that maybe is a bit Iset on his shoulder this year. Compared to the other examples in my flock, it is really hard to tell with him. He is the sire of all four of the lambs mentioned above. I also have this ram's sire, who shows no white fibers at all, even though he's seven years old and his face is turning grey. Main point: I think if I am very observant, I might be able to answer some of my own questions.


This photo shows an unrelated het-grey ewe in the background, and a family trio up front. The center ewe is Sheltering Pines Dolce. She is emsket. Her entire fleece is uniformly modified. She was considered Iset until she was about 2 years old, though. I actually think she is an Emsket Iset. On the left is her black daughter, Boston Lake Delyth. Delyth has been sheared once. She had a rare light fiber here and there. But they were few and far between. I feel her color so far is a very dark cool black. On the right is Delyth's twin, Dova. She is obviously Iset. She still appears dark black at the root level, except for the large percentage of lighter, longer fibers.


Delyth and Dova are not modified. They each carry a modified gene from their dam, but their fiber color is still black. Their sire, Kimberwood Kavan, is the ram that has the faintest hue of lightening on his shoulder. I was not aware of these fibers until his second shear.
This ewe is Windswept Northwind. Her black '07 daughter, Raimin, is behind her. I consider her Iset.
I've heard some breeders comment that Iset will become a dominant trait in the flock if it is not controlled. But I want to know what it is I'm working with. If I know, I can breed for it or breed away from it. And hopefully not by chance. Since I understand Ag, I can control it in my flock. But Iset is not clearly defined yet. And yet it seems to have a stigma. Sometimes breeders proudly announce "Absolutely NO Iset fibers!" when they talk about fleeces. Celebrating that much over the lack of Iset fibers seems to set a certain tone for the reigning attitude toward Iset. I'll admit, the iset fibers in my fleeces don't feel as soft as the undercoat does. And most breeders and spinners want softness in a fleece regardless of the color, pattern, or length of staple. But Iset isn't a fault or a flaw. It just isn't overly popular... sometimes...in quantity...
Maybe it's undervalued? Maybe it's not understood very well? Maybe Iset's mystery makes it a bit of a nuisance? Why do some sheep go Iset and some sheep don't? I think that is a question that could be answered with time and attention. Hopefully I have enough of both to satisfy some of my own curiosity.

16 comments:

Juliann said...

WOW!!

I cannot BELIEVE the cool color that Dolce turned out to be! Awesome!!!

Sabrina Wille Erickson said...

Yeah, she really is a distinct pewter color all the way down to the skin.

Michelle at Boulderneigh said...

Well, according to the breed standard, iset does seem to be considered a flaw. And my understanding of it (mind you, I have owned Shetlands for a shorter period than you and have no iset sheep!) is that the white fibers grow in from the skin. That would mean it is not just the outer part of the fleece that gets light-colored, right?

I'll be interested to see what other, more experienced breeders say

Garrett808 said...

Hey Sabrina! I'm not one to know much about iset but from my understanding it happens in blacks as 'age iset' but not normally until they are older. The iset fibers are very rough, very straight and very hairlike in nature. I have seen several black animals that look like your ewe in the center of the photo....black head and complete iset body giving them the allusion of being emsket or even Ag. You would know by the roughness of it, the straight hair fibers etc. Ag is also deceiving. If that ewe has never thrown a lamb that has gone Ag, it probably isn't Ag either, only iset. Many people like to spin iset fleeces as they are easier to spin (so i've heard). Emsket is a hard one to figure out because a lot of Ag animals appear to be emsket because of the bluish tones. Ag can vary so much, as can iset. But do know that iset is white,straight fibers. If your girl has crimpy bluish fleece then its either Ag on black or she truly is emsket. You'd have to get a photo of the fleece next to the skin to tell. If you did have an emsket iset its pretty rare (and emsket is hard to find! good job!) But it appears to me that she is black with iset. I had a yearling ewe go completely iset and she appears mioget now instead of fawn because the iset lightened her entire body up. Just my opinions. I can email you more information if you'd like? I love your blog!!

Garrett808 said...

Then again I'm not an expert but I've asked quite a few 'shetland experts' about it in detail. Our breed is supposed to be a fleece breed and to me iset is frowned upon as it takes over quickly in a line. People may like to spin it because that is what they are used to or that is what they've only known. Just my two cents.

Sabrina Wille Erickson said...

Hi Folks,
This topic stems from a question I put to the Minnesota Shetland Sheepbreeders Yahoo List. Iset is not a flaw, that much was agreed upon. Iset may not be popular, but the "white hairs" in fleece seems to be in reference to kemp, not iset fibers.
Iset fibers do grow in from the skin level. I'm sorry if I gave a different impression in the post. Though (and I think it was Nancy Krohn that pointed out this observation a while back) the lighter fibers grow longer than the darker whole color of the sheep. That iset fiber grows beyond the main surface of the staple is what allows iset to give the distinct "bluish hue from a distance."
I did not own Sheltering Pines Dolce until she was about 2 years old. She was advertised as a black iset. I was new to Shetlands and accepted that. A friend mentioned that Dolce's fleece looked quite different than her own black iset fleece. I sent a good fiber sample to Stephan Rouse, the original breeder. He communicated back to me that Dolce's fleece is what he would call a "true emsket." She has the pedigree to back it up as well. That is how I come to call her emsket. Since I did not meet her until this color had come in, I am not willing to say she did not appear or show signs of iset for her previous owner. I wouldn't know.
Hope some of this extra information helps put my post in better context. I appreciate the comments.

Sabrina Wille Erickson said...
This comment has been removed by the author.
Sabrina Wille Erickson said...

The post that was removed was a duplicate. I accidently pushed the publish button twice. Sorry.

Michelle at Boulderneigh said...

Boy, Garrett's understanding of iset fibers isn't what I've been told at all. Why would people like to spin iset fleece if it had straight, prickly "hair"? "Kemp" is the term for straight, hair-like fibers, and my understanding is that kemp fibers are black. This comes from fiber judge and former Shetland breeder Ingrid Painter (see current NASSA article on the Shepherd's Extravaganza), whose shoulder I hung over at SE to learn all I could.

This link (http://www.shetlandsheepinfo.com/FLEECE/nassa_breed_standard.htm) is where I got my understanding of iset as a "flaw." It states that "White hairs in moorit and black, and dark hairs in white wool" is a disqualification. Fortunately, iset tends to occur in sheep after they age out of the show string!

Still seeking a lot of education on the ins and outs of our little sheep....

Nancy K. said...

Fascinating theory Sabrina! Keep up the questioning!

As far as Iset being a flaw: it is not. It is listed as a "marking" in the Shetland "Colour Census Illustrated". Right in there between "Ilget" and "Katmoget". The white fibers that are a disqualifying fault are kemp fibers. They are shorter, thicker and very coarse. Iset fibers (in my experience) DO tend to be somewhat coarser than the dark fibers but not nearly as coarse as kemp fibers.

I find Sabrina's corralating of Iset to Ag very interesting. It would be nice to be able to predict the likeliness of it occurring. I love my Iset ewes and would not want to be without one. However, it is also very nice to have a solid black or moorit fleece, without the iset fibers. To each his or her own....

Sabrina Wille Erickson said...

Thank you for all of the comments, folks. I would like to add a few of my own opinions:

1) I feel kemp and iset are two separate/different things. Kemp disqualifies a sheep/fleece. Iset is an acceptable trait.

2) Iset is a dominant trait. (this is theory, but most people seem to agree on it) If one iset gene is present (where ever in the code that gene may be) the trait will show in a sheep.

3) Iset is different from "age grey". I would expect a 10 year old sheep to have the odd fiber here or there. When I say "iset," I mean that a yearling or two year old is showing significant iset. My yearling Dova is a good example. I call it Iset, not age grey, because this lighter fiber is visible in the lamb's fleece I sheared off her. Something is making her lighten in that way, and it isn't age. She hasn't even been bred yet.

4) People do genetic studies on unpopular, unfashionable things all the time: diseases, viruses, polled shetlands, etc. I am not studying iset because I think it's so great. I'm studying it because I could not find satisfactory answers to my questions about it. I, personally, would like to control it in my flock. But here's an example: My one verified Iset adult ewe, Northwind, is an incredible mother. Her bag is the best I've ever seen on a Shetland. Her lambs are little chunks with better conformation than she has. And she is proving to be a very good ewe. Since buying her I've decided that I want to focus on soft crimpy fleeces in my flock. So do I just butcher Northwind since her fleece doesn't fit that description? I could. I might have to if breeding experiments with her don't improve lamb fleeces. But...if I knew how Iset worked I could make more educated breeding matches for her to hopefully produce a lamb from her bloodline that has the fleece I want with her hardiness. THAT is my reason for examining Iset. I don't think certain fleece aspects can be considered taboo.

5) I'm not trying to add value to Iset. Breeders will continue to make their own choices about what they like and dislike. ( I happen to love greys. If I ever leave the breeding world to just keep a spinner's flock, I can promise that it will be comprised entirely of grey ewes and wethers! ) Just like it took some test breedings and study to figure out how to get miogets, spots, polled, etc. It will take a bit of work to figure out how to get, or avoid, iset reliably. I can do a little square grid to predict the chances of a grey ewe throwing grey offspring. I'd like to be able to do that with iset sheep too.

6)I probably have more points but my kids have interupted so many times I've lost the train of thought.
Again, thanks for the interest and the comments.

Michelle at Boulderneigh said...

Here's another possible "monkey wrench" to add to the mix. Lauren Dillon, Carol Kelly and I have all purchased sheep from Beryl Baker's flock in Arizona that seem to exhibit their Ag genes late and lightly. By that I mean they are slow to fade and retain more color upon maturity than most Ag sheep do. Is it possible that some sheep labeled "early iset" are actually "slow-to-fade Ag"?

The difficult part of all this is the different nomenclature we all use. Unless we could all gather in one location with a BUNCH of examples of all ages "on the hoof," we can't be sure that we are all using the same terms for the same colors/markings/patterns. Recently an experienced breeder I greatly respect showed me a sheared fleece she calls emsket. I'm still confused. Instead of having a blue-ish cast, it was definitely a warm, almost brown color!

Sabrina Wille Erickson said...

I agree, Michelle, that it is difficult to have a consensus when we breeders are not looking at the same sheep and not able to visit different flocks across this vast country easily.

To address your points: I feel Ag (Grey) sheep are those with light sugar lips at birth, as well as light areas in their ears, scrotum area, and maybe around their eyes at birth. No matter what color the sheep becomes as an adult-dark grey/grey-brown, or almost white, if they had those tell-tale signs of Ag as lambs they carry at least one Ag gene. I have noticed in my own flock that my heterozygous grey ewe is a bluish color. The homozygous grey ewe I owned was almost white. So whether a sheep has one or two Ag genes might make a huge difference in the adult color.

If a sheep lightens to another color as an adult, but never had Ag indicators at birth (or as an adult) I would prepose that another factor is doing the lightening: such as a modifier causing a shaela, emsket, or mioget, fawn. Or perhaps Iset is causing that effect.

I will try to borrow a camera soon to illustrate my views on color. But I'll do my best to explain them here:

An Ag fleece sample would be dominated by uniformly colored light fiber, with a percentage of dark fibers(sometimes these are slightly longer too) causing a heathered effect. The overall appearance could be anything from almost whitish to a lovely heathered grey or brownish color.

An Iset fleece sample would be dominated by uniformly colored dark fiber, such as brown or black, with a percentage of whitish colored longer fibers. These fibers accept dye. The overall appearance can be sortof dusky to a very pale version of the skin level color. The sheep, however, will NOT have sugar lips, a white ring around the eye, or lighter areas inside of the ears or scrotum region.

A modified fleece sample maybe rather dark or rather pale, but all the fibers will be uniformly silvery or goldish. I'd like to stress that there are MANY shades of silvery and goldish. The sheep will NOT display the Ag light areas at birth-unless of course they are also Ag. (Since the Patterns like Ag, Ab, etc. are found in a different genetic location than the modifier gene, it is possible to have a modified sheep that is covered in white or the badgerface pattern, or even the Ag gray pattern.)

My emset ewe is that silvery color at the skin level. But the more her fleece grows out the more sunbleached toward brownish it gets. By winter she looks like a tan/taupe sheep with a black face. I have to part the fleece to see the pewter color underneath. I will try to post photos of this soon. At first I was confused by this as well, but several breeders have assured me that it is a normal thing for emskets to appear brown on the surface. The only time emsket Dolce has a bluish-cast is the month or two after she's been sheared.

These are my understandings of the colors above. I know the original names used to just reflect the "appearance" of the sheep. So a grey ewe could be called emsket if she had that look, etc. When I use color names I try very hard to use the "genetic" indicator regardless of what the sheep's fleece looks like. My grey ewe, Rachel, has often looked emsket, but she has sugar lips and lighter inner ears, etc. so I call her Ag.

I truly have not been trying to soapbox it here. But I guess these are the definitions I believe in. I hope I have clarified my position and my understanding of the issue for you. I really appreciate this conversation with you. Your feedback has been helpful for me.

Tammy said...

Good discussion! It would be a great thing if all of us breeders were uniform in our descriptions and interpertaions of the various colors and modifiers. I find myself very confused at times! :-) Maybe someone can do a hands on video of colors sometime to help clarify the issue! I have one black Iset ewe, who also happens to have a double coat type fleece. The inner fiber is very soft but the outer longer fibers are more coarse. She is most lovely to look at esp. in the fall as her fleece looks like coffee swirled with cream. I have four of her daughters and one son. Of the daughters, Duckie (Ag grey sire) is very Iset at age two and half. Looks very much like her mother in color already(Rouen, the original ewe is around 7 or 8), Birdie (Ag grey sire) her yearling daughter is beginning to show Iset as well, although not as quickly as Duckie did. Thankfully her fleece quality is nicer. The third and oldest daughter, Rain is 4 or 5 (Ag grey sire)registerd as Ag grey seems to be something else entirely --as she ages she is devloping a very dark bluish grey fleece, which I am becoming more convinced is Emsket (she does have modifieds in her lineage). She has a very nice fleece. The son is a musket so its impossible to tell if he is Iset as well. Another ewe that I sold that is 3 or so is a black ewe that is very Iset. So, that is my experience with Iset. This year Rouen produced a moorit (Moorit Sire) ewe lamb, so it will be interesting to see how she turns out. The Iset seems to be very dominate in this particular family. I don't really mind it in the flock, but I also like the deeper, darker colors as well. The Iset coloring does not seem to affect fleece sales, but is dependent more on the handle of the fleece. From what I have read and heard age greying and Iset are two seperate events.. I think. Anyway, keep up the good discussions! Tammy

Carol Ekarius said...

Sabrina,
I'm tripped on your blog somewhat by accident, but wanted to say I'm glad to know I gave you some inspiration! I believe once you get some permanent paddocks created life will be easier. But, your sheep and pastures look great.
I have never had Shetland sheep and so I don't know enough about their colors to pitch in on most of this discussion, but as for your comment about whether to keep breeding a good ewe (Northwind) who has less than desirable fleece traits or butcher her--my recommendation is keep here if this is the only point against her. If this were a ram, I would say just the opposite because the ram influences so many of your offspring, but with the limit of influence that a ewe has, her hardiness, healthy bag, and other strong maternal traits are the most critical pieces she brings to the equation.

Best,
Carol Ekarius

Kanisha said...

Did you get anywhere with your theory I too have loads of questions relating to Iset although I keep a different breed of sheep and would love to be able to understand the whole process better.any light you can shed would be most welcome
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