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 ;)