In 1998, shearing has been sporadic because of weather conditions. First rule: DO NOT SHEAR WET ANIMALS. Preparation for shearing is very important for the successful harvesting of fiber. The same principles apply to large and small operations. Set up an assembly line configuration with specified duties at each point and provide adequate labor. Include the shearer or shearing contractor in the preplanning process.
The animals should be held a minimum of four hours without feed or water in a dry pen free of contamination. There are three kinds of contamination: natural, acquired and applied.
Natural contaminants include black and colored fiber in white sheep because these fibers cannot be dyed for lighter shades of fabric. Yolk is a combination of suint (sweat) and grease deposited on the wool fibers from the sweat and sebaceous glands. Dung locks and urine stains are also considered natural contaminants and careful feeding and worming practices can go a long way to help in the prevention of serious tag (dung lock) problems throughout the year.
Acquired contaminants are a result of the animal’s environment and they include many forms of vegetable matter: spear grass, grass or weed seeds, burrs, straw, twigs, bark, cactus needles, cedar, and hay chaff.
Dirt, soil, sand, mud, and volcanic ash are mineral contaminants which stick to wool. Dusty conditions should be controlled in holding pens and proper drainage planned in advance.
Horses, cattle, and goats leave fiber in corrals which can be also used as holding pens for sheep. Jute from burlap bags, sisal, rags, cigarette filters, and carpet scraps find their way into wool bags or bales. When cigarette filters shred into wool, their synthetic fibers look like the rest of the fiber, but do not dye like wool. Strange objects have been discovered in wool shipments: styrofoam cups, rocks, combs, toys, beer or pop cans, you name it!
Polypropylene is a major contaminant and is used in baling twine, tarps, feed bags and used or torn wool packs. Some hay balers cut short ends of twine as each bale is tied and these short pieces drop in the field and eventually find their way into the fleece when the fields are pastured. The operators of tub grinders and pellet mills do not always remove the polypropylene twine when ground hay is included as a pellet ingredient and it can then pass through the sheep’s digestive system to contaminate the wool.
Polypropylene disintegrates and causes major contamination in the finished textile product. “Poly” is usually not detected until the fabric is finished unless a significant amount of polypropylene is present in the raw wool.
Applied contaminants are used for identification or disease treatment practices and include paint brands, dewormers and parasite sprays.
In the United States, shearing facilities vary from tents set up in corrals, shearing trailers, and permanent sheds. On the farm, barns are usually the designated shearing area. The area should be large enough to accommodate the number of shearers required.
The space should be well lit and ventilated, and free of drafts that can blow parts of the fleece off the shearing board. The shearing board should be constantly swept clean as each animal is shorn.
Even minimal fleece preparation should include the removal of belly wool, or “bellies”. The shearer removes the belly first and it should be picked up immediately and placed in the “bellies bin”. The removal of off sorts, locks and stained wool can also be included in this “bellies” category.
The main fleece is rolled up in thirds from the rear or britch to the front, fleshy side out, and then bagged or baled. It was the practice for many years to tie individual fleeces with a paper tie. This facilitated the grading of individual fleeces, but it was a cost to the producer and the textile mills had to use equipment to remove the ties.
Fleeces that are “bellies out untied” are classified “BOU”. Less often, “BOT” or “bellies out tied” is used as a description. When everything goes in the bag, fleeces are labeled “BIT” or “bellies in tied”. A lot consisting only of belly wool is referred to as “BLS”, scrap wool or pieces as “PCS” and dung locks as “TAGS”.
Wool is classified as a full table skirt (SK) when the belly wool has been removed and the fleece placed on a skirting table, shorn side down. The skirter identifies inferior pieces of the fleece, detects polypropylene and removes the inferior wool: stains, tags, top knots, heavy vegetable matter, and second cuts.
Careless shearing sometimes results in cutting wool which has already been shorn once. This produces short fibers known as second cuts. Heavy locks and second cuts fall out through the slotted skirting table.
The classer separates the fleeces for fineness (average fiber diameter), staple length, strength, and yield. The strength of fiber is important in that it must be strong enough to go through the textile manufacturing process without breaking.
There are two forms of weakness in fiber: “tender”, in which the fiber pulls apart or “break”, a definite break in the fiber. Both problems result from sickness or stress. Length of staple determines the usage in worsted or woolen textile systems. Yield is the amount of clean wool obtained from grease wool expressed as a percentage.
To earn reputation clip status, a grower’s fiber must be uniform in grade with long, strong staple, low in natural contaminants and free of applied contamination. The classer is also responsible for the bagging and baling of the clip and separating portions of wool into appropriate lines, or classifications of fiber diameter, length, color, strength, and degree of contamination.
Classing is a continual process and the record of how the clip was classed is passed to the owner to help him sell the clip. The process of quality control for next year’s clip starts all over again at shearing time.
For more detail, contact ASI for a copy of the “Code of Practice for Preparation of Wool Clips in the United States”.
Reality Check: Testing Talk
Since our website’s first appearance on The Fourth of July, 1996, we have focused on average fiber diameter testing of individual animals: alpacas, goats, llamas, sheep, and rabbits. Most of our business is based on testing commercial lots for both yield and average fiber diameter.
Yield testing determines the amount of usable fiber in a given lot of a specific weight, e.g. a 10,000 pound lot with a 60% yield would inform all concerned in a sales contract that 6,000 pounds of fiber is available for processing of that lot. Concerned parties in the contract can include wool growers, warehousemen, dealers and textile mills.
Yield and the percentage of vegetable matter (VM) are determined to minimize risk to both buyer and seller. VM is described as the presence of burrs, twigs, and grasses and is affected by feed and grazing conditions. The percentage of VM affects overall price because of high processing costs and fiber loss at the mill.
We also test scoured wool for moisture, VM, and fiber diameter (AFD); “top” for moisture, oil content, VM, colored fiber, neps (processing defects), length, and AFD. Top is the result of a carding and combing process that delivers a rope of fibers in a parallel configuration in the worsted processing system. Testing for percentage of oil content in top is performed to determine how much oil was added during the carding and combing process.
Commercial lots of wool and mohair, alpaca, cashgora, cashmere, dehaired camel, yak, and llama, as well as yarn and cloth samples, are tested for fiber diameter and coarse hair content. Special testing is performed by request.