Skip to Content

The Weekly News Source for Wyoming's Ranchers, Farmers and AgriBusiness Community

Wool contamination issues suppress prices for U.S. sheep industry

by Wyoming Livestock Roundup

Greeley, Colo. – U.S. wool contaminated with straw, poly fiber, manure and other contaminants isn’t worth as much on the world market as Australian wool. 

“Wool that’s clean gets more green,” Lisa Surber told producers at the First Annual Sheep Day held during the Colorado Farm Show on Jan. 25. “Contamination is a tremendous cost to our industry. Anything that is not wool is considered a contaminant. It impacts how wool is processed all the way through the chain.” 

Surber, who is the raw wool services consultant with the American Sheep Industry Association (ASI), said contamination can come from several sources but is labeled as natural, acquired or applied. 

Natural contamination

Natural is defined as contamination produced by the sheep like impure fibers, urine, dung and wool wax. These natural contaminants should be sorted from the white wool after the shearing process, she said.  

“Shedding breeds or crosses can still have hair fibers in their wool, even if the cross was three or four generations ago,” she said. 

Top knots, leg hair and hairy britches that creep up from the legs and down from the head in some breeds are also considered contaminants. 

Addressing the problem

Surber urges growers to separate sheep with freckles on their face or black eyelashes from sheep with true white wools. 

“They tend to have black fibers in their wool, even if it isn’t obvious,” she said. 

She encourages producers to shear the finest wool white fiber sheep first and work down from there, doing the black fiber sheep, then the hair sheep last. 

Wool should be sorted and bagged as it is sheared.


Acquired contaminants are harder to separate from wool and can really decrease value, she explained. Vegetable, mineral or animal matters, polypropylene, jute, strings and cigarette fibers are all considered acquired contaminants. Examples are burrs, burdock, straw and wood chips. 

Polypropylene, which is found in twine, blue tarps and agricultural tote bags, is considered one of the most troublesome contaminants because it is virtually impossible to pick out of wool. 

“There is no sense of pride in the wool clip if we present a buyer with wool that has this contaminant,” she said, showing a picture of a fleece with twine thrown into it. 

It can also be dangerous if the sheep ingests it. It can create a ball in the rumen, causing compaction and other health issues, she said.


Wood chips or straw shouldn’t be used to bed sheep right before shearing. Surber recommends waiting until after the sheep are sheared, or doing it a week or more in advance so the animals can trample it down, if it’s really cold.

Examples of applied contaminants are paint brands, pesticides and medications. Paint brands and grease markers should be used carefully. 

“Paint can turn a scourable product into an unscourable one,” she explained. 

“White wool can become pink, and blue paint produces the biggest problems,” she said. “If producers have to mark a sheep, do it on the face or someplace where the least expensive wool is. Definitely not down the back.”


Surber told producers they should place wool with contaminants like vegetable matter, polypropylene, stained wool and belly wool into a separate bag. Wool stained with urine, feces, yolk or canary stains should also be placed in a separate bag. 

“Belly wool tends to be shorter, uneven, stained and lower yielding,” the wool specialist said. 

China purchases belly wool from the U.S., but they have started rejecting fleeces with too much manure. 

“Why would a producer even put manure in the wool bag? During shearing, remember that what happens in a couple minutes can impact what they have spent all year building,” Surber told producers. 

Opportunities in wool

With the addition of the Super Wash system in the U.S., new markets for wool products have opened up domestically. The Super Wash system changes the wool fibers so they can be machine washed and even tumble dried on low. 

“It has created the ability to market and sell wool to people we never could before,” she said. 

It has also expanded markets for items like wool socks, shoes, clothing and blankets. 

“If we could get everyone in the U.S. to buy wool socks, it could be a game-changer for the U.S. wool industry,” she stated.

The largest market for wool is the U.S. military, which utilizes clothing made from U.S. wool, thanks to the Berry Amendment. 

“One of the most important characteristics of wool is its ability to wick moisture away from the skin. Wool can absorb 30 percent of its weight in moisture, without feeling damp. Wool is a warm and cool season fabric and is resistant to flame, which makes it popular for the military,” she said.

Wool is also considered a “green” fabric because it has natural protein fibers. The chemical bonds will break down when the wool is exposed to elements of nature. “Wool clothing and other products will last a long time, but if they ever end up in the landfill, they will break down and become part of the soil,” she explained. “Discarded wool has very little impact on the natural environment and because of this, wool is environmentally friendly.”

Recycled wool is very popular,” she continued. 

Old garments or cuttings can be used to make new garments or respun back into yarn. 

Finer micron wool

Surber told producers countries like China are looking for finer micron wool. 

“There is an increasing demand for next to skin circular knit wool clothing for active and leisure wear,” she explained. “U.S. domestic users also want finer micron sportswear and some military clothing.”

Breeds like Merino, Rambouillet and Targhee are all capable of producing these finer wools. 

“It will be a big challenge for us to produce enough wool that is more than 20 microns to meet the needs of the specialty fabric market in the U.S.,” she stated.  

Gayle Smith is a correspondent for the Wyoming Livestock Roundup. Send comments on this article to

Back to top