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Wool quality and pricing are determined by a multitude of factors

by Wyoming Livestock Roundup

Riverton – “The wool check will be good this year, and we don’t want to miss out on it,” said University of Wyoming Extension Sheep Specialist Whit Stewart. 

Stewart addressed producers from in and around Riverton at the annual Fremont County Farm and Ranch Days, held in early February. He stressed the importance of selecting quality replacements and rams, as well as producing clean wool. 

Quality determinants 

Stewart pointed out there are many determinants in wool quality but specifically discussed micron, yield and vegetable matter. 

Stewart defined micron as the diameter of the fleece fiber. Wool with a smaller fiber diameter will grade as finer, and larger diameters are considered coarser. 

While micron is a quality indicator, he said producers should be paying attention to and using it as a determining factor in their herds, they should not sacrifice yield for micron. 

He also discussed the important role vegetable matter plays in determining the quality and ultimately pricing of a fleece. 

“We have a lot of control over vegetable matter, and it’s something we can control with how we feed,” Stewart explained. “If we have poly twine or other foreign material in the wool, it can lead to the complete loss of wool at the first-stage processing level.” 

Stewart explained producers want to have vegetable matter as low as possible, but the typical range is between one and 1.5 percent. He noted anything above two percent vegetable matter can result in significant price discounts.

“Vegetable matter is what will dock us the most at the end of the day,” said Stewart. “This is the most overlooked quality of wool we can actually control.”

Grading wool

Stewart distributed a Montana Extension handout explaining the three main grading systems used in the wool industry, the American or blood system, the English or spinning count system and the micron system. Each of these three systems measures the average fiber diameter and can be used interchangeably. 

In the American system of grading, wool grade is defined as the percentage of merino blood carried by the sheep that would typically produce a particular fineness of wool. The terms used are fine, low, common and braid. 

Stewart pointed out these terms are not as precise as other systems. Due to its ambiguity, the American or blood system has become nearly obsolete. 

The English system of wool grading has much narrower ranges of diameter and provides a numerical designation for fineness. The system measures the spin count and is based on the number of hanks that can be spun from one pound of clean wool. 

The micron system came about as the emphasis on precisely measured diameter became more popular. The unit of measure is the micron, which is one-millionth of a meter or 1/25,000th of an inch.

Choosing sheep

“I’m not telling anyone what sort of sheep to run or what decisions they should make,” Stewart said, “but I caution producers to pay attention to length and total fleece weights in additon to micron.”

Stewart explained he teaches his wool judging students to measure their middle finger and use it as a tool to measure the staple length of wool on the grading rail. 

“We really don’t want anything under three inches,” he explained. “We want to select for overall uniformity and identify outliers in the flock throughout the year.”

Stewart noted the simplicity of utilizing wool labs to ensure we are staying within a specified micron range. 

Producers should cut a side sample with scissors all the way down to the base layer of the wool and put it in a bag with identification to send to a wool lab. This is especially important in testing wool on replacement rams older than one year, as they will make up the greatest contribution to the flock. 

Stewart also noted it’s important not to sample the shearling fleece, which comes from sheep less than one year of age, as the shearling fleece is significantly finer and doesn’t truly represent what that ram will produce throughout his lifetime.

“At three dollars per side sample, it’s very hard to argue against utilizing wool labs,” Stewart said. “When we get the results back, they help us know what the wool on replacement animals is.”

“As technology has progressed, we can measure the micron of a fleece more accurately than ever before,” said Stewart. “But we can’t fall into the trap of using micron as the only determinant in how we select sheep.” 

Stewart stressed the importance of establishing wool and broader selection criterion by the individual operator based on long-term, economically relevant data. 

He said producers should “determine where they are with their wool and where they want to be, and then stay there.”

Wool economics 

“Yield is an extremely important factor in wool production,” said Stewart. “The quickest way to increase revenue is to increase yield.” 

Stewart challenged ranchers to pencil out each decision they make to determine whether or not it’s profitable. 

He used the example that, in the end, a 19 micron as opposed to a 21-micron wool may only bring marginal returns. While it’s always appealing to chase finer wool production, there is a threshold that can result in lighter fleeces with smaller staple lengths and, in some cases, tradeoffs in lighter lambs being produced. 

In our region, a heavy shearing 20 to 25 micron ewe will always be marketable, he said.


He explained the USDA National Wool Review produces prices based on the Eastern market or Australian indicator. 

“This information is produced for the public and should be checked weekly or at the least before marketing,” said Stewart. “Knowing this information gives us a ballpark of what we might expect for our wool.” 

“The sheep industry has had some ups and downs through the years, but wool is good, lamb is decent, and there are real positive indicators in the industry right now,” said Stewart.

Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to

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