Monday, August 23, 2010

Shetland Microns and learning new things!

Kara's post to the Chat With NASSA list today made me think of a post I've been wanting to write about for a while.

Before I dive in, I wanted to repost my 2009 entire flock micron average for just the Shetlands. I realize that the BFLs have much lower SD and CVs and would bring the flock averages WAY DOWN for those so I removed those. I did include all ewes and rams, mature and yearlings.

AFD 25.4
SD 5.7
CV 22.5
CEM 10.9
CF 80

I sold 15 sheep since then, all to new breeding flocks (some registered flocks, some unregistered flocks). Once those rams and ewes were removed these were my averages:
AFD 25.3
SD 5.6
CV 22.2
CEM 8.6
CF 93.5

The first three numbers were basically the same, although slightly lower. The CEM and CF however improved greatly. I did sell some animals that had higher CEM and CF. But I also sold some of my very lowest CEM and CF sheep as well. Its surprising what one can improve upon just by selling some animals huh?

At Black Sheep Gathering I gave a genetics talk to the BFL group at their National Banquet. After that talk, Martin Dally of SuperSire Ltd gave a talk solely on Micron Testing and reports.

1. Micron results should NOT be compared between different groups fed differently or separated, or compared to DIFFERENT FLOCKS on different farms!

This mind boggled me. Why would we? Martin told us that there are SO MANY factors that lead to wool testing that each pen or age group or pasture or flock or farm will read differently and not to be compared across the country.

So if my ewe lambs are fed and housed apart from my mature and pregnant ewes, their microns should NOT be compared as equals. Granted you can get a rough idea between the two groups but should NOT be compared with other animals from other pens.

That means that my rams should NOT be compared to my ewes, or ewe lambs, or ram lambs, unless they were all together, for an entire year in the same pen, eating the same food. This also means that my BFLs were house separately from my Shetlands and fed differently, so their microns should NOT be compared to any other group.

Now the ewes have been housed in the same pastures all summer since about May 1st. If I took a fall test of ALL the ewes then I could compare them across the board as they've been house and fed in the same conditions.

2. Sample collection and time of the year will also have an affect on your results!

The month of the year where the fleece will be the finest at the skin level (where you cut the fibers from the animal) will be the month of March through May 1st. The highest number will be in the fall, September/October. March is a good indicator of the finest wool follicles reaching their peak for fineness. In the fall months, the wool follicles have not had an opportunity to work as hard over the bitter cold months. Your finest wool is produced during the winter months.

3. The third to last rib, mid side is the preferred location on Merinos to do fleece samples!

When I questioned this he said many other breeds also do third to last rib, mid side. I told him that YoCom-McColl and Texas A&M recommend last rib. Martin felt that that was too far back on the animal to give a good indication of what the 'average' micron of the animal was.

I still don't fully believe this and still will do last rib, mid side as that is what all of us Shetlander's are doing.

4. Different parts of the fleece will be different in microns.

Now I understood this, but in Merinos (where Martin has had 20+ years breeding them) the change in micron is really only 2-4 microns over their entire body, not 20 microns like many Shetlands are. Also depending on the breed, it will differ.

5. Ideal age for micron testing is 16-18 months of age

Martin emphasized that ewes have not lambed yet so there is no stress from being pregnant, and rams are ideal at this age to micron test. He said never to micron old ewes past age 6 as at that age (six) will be the most coarse the ewe will be, before SLIGHTLY getting finer with old age. Slightly being 2 microns at most. This example was in a 21 micron flock of Merinos. The ewes barely changed from 1.5 years of age until 6.5 years of age, only going up maybe .3-.5 microns. (COULD WE ONLY WISH OUR SHETLANDS DID THIS SLIGHT INCREASE?!)

So take this all for what its worth, a grain of salt. I most likely will NOT take any drastic changes to my schedule as i usually collect fleece samples in March/April anyway, and since I do micron test yearling (even my crosses and old ewes) I do find that the oldest ewes rarely change much and by age 6 we will know for sure what they will be.

So ends today's lesson ;)


Theresa said...

So Garrett, which is better? To test a 16-18 mo old ewe at the coarsest time (Sept) or to wait till she is 2 (in March, the finest time)? I would think the Sept reading would be higher than the March reading and the March reading would give you better undercoat results, regardless of pregnancy influence.

But, like you say, farm to farm varies so much, and flock within flock (rams vs. ewes), so you must compare apples to apples.

Very interesting! Thanks for posting! It's got me to thinking . . .

Franna said...

Hmmm, well, yes. I take it all with a grain of salt. As you noted, we need to be consistent with sample location, and while feeding and management make a difference, I'll still compare your results to mine, especially when I'm looking to bring in outside genetics. It doesn't make sense to throw out micron test results (or not test at all) just because the sheep might be managed differently. Test results are a lot more concrete than someone's opinion and "hand".

Karen Valley said...

I agree with Franna as one can always take into account the variables involved such as feed sources and condition of the animal...dry lot vs. lush grazing...length of time on grasses, etc. It is nice to know at least where one is starting with a mature animal even if given a better nutrition level the results go up on the next test. Thanks for the details on testing. It was something I had seen from testing at various times of year, but I haven't had the decades to prove it out.

Becky Utecht said...

I'm wondering if Martin was thinking of micron testing as a tool for gauging the nutrition status of an animal (by looking at the graph on test results that shows the fineness along the staple length). That would be the only reason I could think of for him to recommend not comparing animals in separate pens. And even that's pretty shakey ground.

Garrett808 said...

Hi Becky -

Martin emphasized quite a few times not to compare flocks or different pens as their planes of nutrition could affect the micron results. So if your rams were never supplemented but your ewes were before lambing, this could in fact alter the comparison for their yearly fleece tests in a greater than thought of way.

Its just a tool, but its interesting to hear some very different things that he mentioned that I hadn't thought about, like the comparing from flock to flock across the country.

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