A972
Wool - Factors Affecting The Value

1. Colored fiber contamination
2. Excessive vegetable matter contamination
3. Branding paint stains
4. Tender or "hunger-fine" fibers
5. Chemical contaminants
6. Heavy urine and fecal stains
7. Mixed fiber types present, i.e. kemp and medullated fibers. Many other types of wools with obvious negative faults would be considered in this category.

Generally, these marginal wools have limited use outside of the normal processes. In recent years, some research and development has been undertaken to investigate possible market uses for so called marginal wools.

1. The finer the fleece the more value.

1. Dirt - The more dirt, the lower the yield.
2. Grease - The more yolk (oil + suint [sweat + salts]) the fleece contains, the lower the yield and the lower the value.
3. Length - The longer the length of staple, the higher the yield and value (if fiber diameter is less than 22.9 microns).
4. Moisture - The more water, the lower the yield.
5. Vegetable matter (VM) - The more plant material contaminants (i.e. burrs, straw, seeds, etc.), the lower the yield.

1. Colored fibers - Any colored fibers reduce purity.
2. Medullated fibers - Any medullated (has a core), hair-like, kemp, and heterotype fibers impact purity negatively.

1. The more uniform the fiber diameter and staple length of the fleece, the higher the value.

1. Wool with "breaks" or evidence of "tender" and "hunger-fine" fibers are of less value. The strength of the fiber is affected by the environment in which it is produced, i.e. nutrition, disease, parasites, weather, etc.

1. This refers to the brightness and attractiveness of the wool. The character is determined by the following subjectively evaluated criteria:
   1. Handle (tactile property)
   2. Color (the more whiteness, the better)
   3. Crimp (the degree of fiber waviness or crimps/inch; the more crimps/inch the finer the fiber.)

Wool faults are defects that lower the value for manufacturing purposes; they can be grouped roughly into four types:

• Faults due to age, genetics, and inherited defects - These are faults that can most often be controlled by genetic selection; however, improvements made here can be slow and require careful selection of breeding stock.
• Faults due to the environment - Some of these are often beyond the control of the wool producer.
• Faults due to poor management - The wool grower often has the most control over these faults.
• Faults caused by infectious agents and insects.

1. Age, Genetic, and Inherited Defects:
   1. Hairy or medullated wool - This wool is coarse and relatively straight. It has a chalky appearance, a thick medulla (core), and a thin cortex.
      
      
   2. Kemp (used in tweeds) - This wool has a sharp pointed tip and the base of the fiber terminates in a bulb or brush. The fiber is short, flattened, and has a chalky appearance. The fibers may show abrupt kinks.
      
      
   3. Black, brown, and grey pigmented fibers - This defect is caused by melanin granules produced by cells called melanocytes. It can effect both skin and wool.
      
      
   4. Stringy yolk - This describes strings of yellow, greasy material (1/8 of an inch across) that lay perpendicular to skin. This yellow material is caused by over active sebaceous and sweat glands that produce excessive amounts of yolk (oil + sweat + salts). The excessive yolk is most often produced by a very localized patch of skin.
      
      
   5. Doggy wool - This problem affects older sheep and causes a lack of crimp in the wool. This wool has normal tensile strength and a lustrous appearance.
      
      
   6. Cotted or matted wool - This problem is caused by frequent wetting of the wool in animals that lack uniformity in their fleeces. This results in entanglement of the fibers of the legs, belly, side, and back. Cotted wools are classified as "soft" or "hard" depending upon degree of cotting. This problem can be caused by genetics and environmental influences.
      
      
2. Faults Caused by the Environment (weather, earth and vegetable matter):
   1. Non-scourable (does not wash out) canary yellow - This problem occurs in sheep of all ages and results from high temperatures and high humidity. This discoloration occurs on the belly wool first and then moves to the other low parts of the fleece.
      
      
   2. Yellow banding or fleece rot - This condition affects the back wool on fine wool breeds. It causes yellow horizontal bands where the yolk is dry and hard, but becomes doughy when wet. Wet skin surfaces and poor draining due to problems in the fleece cause the yellow banding. Despite the name, the fleece does not actually become rotten. This condition is due to genetics and the environment.
      
      
   3. Weathered wool - Wool that is exposed to repeated wetting and excessive or intense sunlight will be brittle and lack normal strength. These conditions can often cause the loss of normal wool production on the back areas. When dyeing weathered, damaged wool, the weathered tip end will dye lighter than the unweathered butt end.
      
      
   4. Dingy wool (sandy, earthy, dusty, muddy) - Wool that is discolored because of dirt and dust will be weak, contain more yolk, and receive lower prices.
      
      
   5. Seeds and burrs - Wool that contains plant contaminants will be graded lower and can be docked in price if it is difficult to remove the burrs/seeds.
      
      
   6. Bracken fern stain - The bracken fern can cause a brown discoloration of wool during spring and summer grazing. The fern itself actually stains the wool in a way that cannot be removed by scouring. This discoloration can result in a large price penalty at the time of sale.
      
      
   7. Log stain (charcoal) - This discoloration is caused by dust or ash that is collected when sheep are grazed in areas that have been burned. This causes a grey to almost black discoloration to the wool that is scourable.
      
      
3. Faults Caused by Poor Management:
   1. Weakness or breaks in the wool - This can be caused by abrupt seasonal changes or conditions that cause stress on the animal. Stress causing situations include poor nutrition, disease, pregnancy, parturition, lactation, and sudden exposure to cold and wet conditions. These situations cause a narrowing of the fiber and a resulting defect.
      
      
   2. Copper deficient wool (steely) - When nutritional levels of copper fall, changes in the wool are often seen. These changes include loss of crimp, loss of tensile strength, and abnormal pigmentation in colored sheep. This problem can be confused with doggy wool, with the exception being that copper deficient wool is weaker than normal.
      
      
   3. Scourable (able to wash out) diffuse yellow - This problem causes "butter colored" wool and can happen to long-wooled breeds that are on high feeding programs before a show or sale.
      
      
   4. Fecal stain - Staining of the wool surrounding the anus and hind legs can occur when fecal material contacts these areas. Carotene and chlorophyll from green plants found in the feces stain the wool a yellow to green color. The discounted price for these wools can often be avoided if crutching is utilized.
      
      
   5. Dipping damage - Many dipping preparations contain traces of coloring materials like CuSO4 or bluestone (copper sulfate) that can stain the wool. Using dirty dipping vats can also cause banding or "dip marks."
      
      
   6. Phenothiazine stain - Phenothiazine is an olive-green powder or liquid suspension that is commonly used against internal parasites. Careless drenching, leaking guns, dirty hands, or slobbering of sheep will stain the fleece a permanent blue-black in color. Feces and urine of treated animals can also stain the wool a bright red.
      
      
   7. Brands - Brands are colored materials used to mark the wool of sheep. Brand marks are considered an outright fault and a definite markdown in price. Some countries outlaw the application of colored materials to the fleece.
      
      
   8. Skin bits - These are actual pieces of skin from the sheep still attached to the wool fibers (locks). These are caused by sloppy, careless, and inexperienced shearers.
      
      
   9. Second cuts - This is a procedure where the shearer will go over a shorn area a second time and cut off a very short layer of wool. The resulting short fibers have no commercial value and lower the overall worth of the fleece.
      
      
4. Faults Caused by Infectious Agents and Insects:
   1. Dermatophilosis (mycotic dermatitis, or lumpy wool) - This is a bacterial infection of the skin caused by an organism called Dermatophilus congolensis. It can occur anytime of the year and affect any age of animal. The young, fine wooled breeds are most susceptible. The infection produces a discharge or exudate that causes the fibers to be cemented together. The disease is thought to be spread by contaminated equipment or insects. This makes culling of infected animals essential in controlling and preventing the spread of the disease.
      
      
   2. Green and brown banded stains - The discoloration is caused by the bacterial organism Pseudomonas. It affects sheep with both fine and coarse wool. The organism can be found in the soil and water, and thrives when the fleece remains wet for long periods of time.
      
      
   3. Blue banding - This is also caused by Pseudomonas. This rare problem is scourable (can be washed out of the wool) and is also caused by prolonged wetness.
      
      
   4. Black fungus tip - This disease is caused by a fugus that damages the last 1/2 inch of fiber tip. It causes a black, permanent discoloration in wool that is grown during high rainfall conditions.
      
      
   5. Pink tip - This problem is caused by bacteria that flourish in cold, damp environments. They cause red to light pink discoloration (up to 1 inch long) in the fibers of black wool. The discoloration is scourable.
      
      
   6. Pink rot - This problem is also caused by bacteria that flourish in damp environments. The bacteria cause the fiber to deteriorate (from 1-2 inches). All breeds and wool types are affected. Keeping the fleece dry and exposed to good ventilation is essential in preventing this problem.
      
      
   7. Diffuse yellow or apricot stain - This condition is common on the lower parts of the fleece where the belly is consistently damp due to rainfall and long, damp pastures. This problem is not scourable and causes severe fiber damage.
      
      
   8. Purple stain - Bacteria cause horizontal bands of reddish to purple discoloration to be formed in the wool. The purple can be washed out, but doing so will leave the wool a pink color. Keeping the wool dry is important in preventing this problem.
      
      
   9. Ked stain - Sheep keds (Melophagus ovinus) are wingless parasites that feed on the blood of animals. Though commonly called sheep ticks, they are not actually ticks. The ked is reddish to grey in color, about 1/4 of an inch long, and has six legs. The parasite moves rapidly from animal to animal, with moderate to heavy infections causing severe damage to the wool. The ked causes damage to the wool in two ways. First, if the parasite load is great enough, the keds will suck enough blood to severely affect the nutritional health of the sheep. This will cause poor wool growth. Secondly, the excrement of the keds will stain the wool a reddish color and pupal stages of the ked can be found in the wool. The ked also causes damage to the skin (often called "cockle") and a pungent smell. Controlling this parasite can be accomplished by dipping, spraying, dusting, and using certain pour-ons.
      
      
   10. Leg lice - These sucking lice cause a spongy, sour smelling mass to occur in the wool. The most commonly affected areas are the dew claws, shank, scrotum, and belly. The louse is blue grey to brown, has a life cycle of 43 days, and can live up to 18 days off the sheep. These infections can be spread by direct contact between animals or when uninfected animals are exposed to a contaminated pasture.