Fibers Flashcards
How many layers does the coat of wild sheep have, one or two?
Two.
What is the outer coat of wild sheep composed of?
Coarse, medullated hair.
What is the inner coat of wild sheep composed of?
- Wool.
- A heterotype fiber intermediate between hair and wool.
What did wool producers select against the presence of in the coat of sheep, resulting in its removal?
Guard hair.
What are the two types of wool follicles?
- Primary follicles.
- Secondary follicles.
What are the characteristics of the primary wool follicle?
- Largest.
- Develops first.
- Develop in trios.
What are the characteristics of the secondary wool follicles?
- Produces smaller, finer fiber.
- Develop later than primary follicles, but mature after birth.
- Lack sweat glands and arrector pili muscle.
What is the correlation between the number of primary follicles and the number of secondary follicles as the sheep ages?
Negative, the number of primary decreases as the number of secondary increases.
What breed of sheep have the finest wool?
Merino.
What makes wool different than hair?
- Lack of medullation.
- Crimping.
- Diameter of an individual strand (17-40 microns).
What is hair, gare, heterotype, or med in sheep?
Fiber produced by sheep that lacks crimp.
*Difficult to detect with the unaided eye.
What is kemp?
Brittle, chalky white, coarse, short, >50 microns fiber that does not accept dyes.
What fabric is kemp used to make?
Tweed.
What is the thermal property of wool?
An excellent insulator and rapidly wicks moisture away from the body.
What is the moisture property of wool?
Wool can absorb up to 34% of its dry weight in moisture before feeling damp.
What is the elasticity property of wool?
The molecular structure and crimping.
What is the strength property of wool?
Possess 62-80% of the tensile strength of human hair.
What is the electric property of wool?
Poor conductor of all electricity except for static.
What is the fire resistance property of wool?
Wool burns, but only if held in the flame, otherwise it will self extinguish.
What is the acid resistance property of wool?
Wool is generally resistant to acids, except for concentrated and/or hot ones. These are used to hydrolyze wool.
How does wool react to exposure to bases?
Strong bases hydrolyze wool.
How does wool react to exposure to sunlight?
UV light yellows or browns the wool and results in frowzy tips.
How does wool react to exposure to heat?
At temperatures of 212 F+, yellowing, browning, NH4 release, and HS release occur.
How does wool react to exposure to cold?
When exposed to extreme cold (liquid nitrogen cold), wool becomes brittle.
What does the number of wool fibers an animal produces depend on?
Genetics.
What 3 factors affect the rate of growth of each fiber?
- Genetics.
- Health.
- Nutrition.
What are the 2 ways of determining wool value?
- Coring the sample by hand with a tool or using a machine.
- Visual or subjective assessment.
What is yield as it refers to wool?
The amount of useful wool present.
What influences the yield of wool?
- Water.
- Wax.
- Vegetable matter.
- Suint (grease and sweat).
- Dirt.
What is the average yield for most wool in the U.S.?
45-55%, possible to reach 60-70%.
What 3 methods are used to determine average fiber diameter?
- Blood grades.
- Micron system.
- Spinning count system.
What does the blood grades system entail?
Looking at what percentage of a sheep’s genetics is Merino/Rambouillet breeding.
*Oldest system.
What does the micron system entail?
Measuring the actual diameter of the wool using machinery.
*Most commonly used worldwide.
What does the spinning count system entail?
Determining the number of hanks of yarn which can be spun from one pound of wool top.
How long is a micron?
1/1,000,000th of a meter or 1/25,000 of an inch.
How long is a hank?
560 yards or ~186.67 feet.
Where do 2/3 of fibers from a sheep’s pelt fall when compared to one another?
Within +/- 1 SD of the mean.
*Smaller number=more uniform sample.
Why is a more uniform sample more desirable?
It creates a better product.
What is the most important property in determining quality and value of wool fiber?
Average fiber and diameter.
What sensation does fiber coarser than 30 microns produce when in contact with skin and why?
- A prickling sensation.
- They do not readily bend when pressed against skin.
*Fibers meant to be worn against skin must contain 95% or more fibers that are 30 microns or less.
What are the 5 major types of vegetable matter found in wool?
- Bean burr.
- Cockleburs.
- Sand burrs.
- Shives (small plant fragments).
- Spiral burrs.
Why is wool with excess vegetable matter sold at a discount?
Due to the extra mechanical and/or chemical processing it required, potentially weakening the wool.
How can wool being discounted for vegetable matter be minimized?
Careful management and skirting the sheep’s wool before shearing it.
What is staple length?
The way that animal fiber is measured that determines the average length of a piece of fiber.
Why is it important to test staple strength?
If the sheep that produced the wool was subjected to prolonged stress (dehydration, illness, pregnancy, starvation, etc.), the wool often grew in weak during that time. This results in broken wool, where there are weak spots in the staple where it can be pulled apart easily.
What is tinder wool?
Wool that is overall low strength and the staple breaks over wider, indefinite areas.
Why is white wool more valuable than colored wool?
White wool can be dyed any color the manufacturer needs it to be, while colored wool can only be used for certain things.
What does variability in fiber diameter and staple length cause?
- Reduced spinning performance.
How is variability in fiber diameter and staple length minimized?
- Good shearing practices.
- Health maintenance.
- Management.
- Selection.
What constitutes good shearing practices?
No second cuts.
What constitutes health maintenance?
Avoiding nutrient deficiencies and disease in the flock, which will result in breaks in the wool.
What constitutes good management?
Short wool on the belly (a skirt belly), legs, head, and other short wool.
What is cotted or felted fleece?
Fleece that has gotten wet and has matted together on the sheep.
What does a large amount of cotted or felted fleeces?
A large amount of waste when carded and combed.
What is the correlation between crimp and fiber diameter?
Inversely correlated.
What happens to low crimp wool during scouring?
It entangles and felts.
What are the 4 important points in quality wool production?
- At mating.
- Around time of birth.
- At harvest.
- After each year’s wool harvest.
Why is mating an important point in quality wool production?
This is where the genetics that determine wool quality and amount.
Why is mating an important point in quality wool production?
This is where the genetics that impact number of fibers and wool quality is determined through selective breeding.
Why is around lambing an important point in quality wool production?
This is when the number of primary follicles is maximized and when secondary follicle production begins increasing.
Why is at harvest an important point in quality wool production?
It allows for producers to assess what the quality of the wool from each animal and from the entire flock.
Why is immediately after each year’s wool harvest an important point in quality wool production?
This is when management decisions for the following year will be made.
Why is an objective measurement a good thing to use for assessing wool quality?
It tells you what it is, not whether it is good or bad.
What 3 conditions result in fewer wool follicles developing in lambs?
- Multiple births.
- Undernourished mothers.
- Young mother.
How much more wool will open ewes produce as compared to single bearing ewes? Twin-bearing?
a. 10-20%.
b. 14-24%.
What do drastic changes in fiber diameter lead to?
Weakness in the fiber strength that can impact processing ability.
What are sheep keds?
Wingless, blood-sucking flies.
What is the puparium?
The last larval stage of the ked?
What does a heavy infestation of keds cause the fleece to look like?
Discolored and stain.
What physical effects do the sheep keds have on the sheep?
- Reduced weaning weight.
- Reduced fleece weight.
- Reduced pelt value.
How is an infestation of sheep keds treated?
Applying insecticide immediately after shearing.
What are the 5 ways the overall quality of the wool preserved at harvest?
- Minimization of contamination.
- Properly prepare sheep and facilities.
- Properly store wool.
- Scheduled shearing.
- Sort different types of wool.
What are the 3 types of wool contamination?
- Natural.
- Acquired.
- Applied.
What are the 4 kinds of natural contamination?
- Colored fibers.
- Dung and urine.
- Hair.
- Yolk.
How do colored fibers contaminate wool?
It may keep the wool from being pure white, making it less valuable to sellers.
What do dung and urine do to wool?
Stain it.
How does hair contaminate wool?
Hair is difficult to detect, virtually impossible to remove, and will not accept dye, decreasing wool value.
What does yolk do to wool?
In excess, it reduces clean fleece yield.
What are the 7 kinds of acquired contamination?
- Animal matter.
- Mineral matter.
- Polypropylene (Baling twine).
- Vegetable matter.
- Canary Yellow/Yellow Banding.
- Sheep Keds.
- Binder twine, cigarette filters, jute, rags, string.
What is the animal matter that contaminates the fleece of sheep?
Fiber from hair sheep, cashmere goats, llamas, cattle, dogs, donkeys, and horses.
How does mineral matter contaminate sheep fleece?
Blowing soil and sand.
Why is polypropylene a difficult contaminate in sheep fleece?
It cannot be chemically or mechanically removed.
What is the vegetable matter that contaminates sheep fleece?
Hay, seeds, straw, and other plant materials.
*Some is unavoidable.
What is Canary Yellow/Yellow Banding?
Discoloration of the wool associated with wetting of the fleece.
What are 3 kinds of applied contamination?
- Insecticide.
- Paint brand.
- Phenothiazine (thiodiphenylamine).
What part of the fleece does the insecticide contaminate?
The lanolin in the fleece.
What country are paint brands illegal in?
New Zealand.
What paint brands used as?
A management and identification tool.
What is Phenothiazine (thiodiphenylamine)?
An old, grayish-green or olive-green, drench dewormer.
How does Phenothiazine (thiodiphenylamine) contaminate the fleece?
It stains the fleece blue-black. Causes the urine and feces to turn bright red, potentially staining the wool the same color.
When should shearing be scheduled, if possible?
Before lambing, to prevent the stress of lambing from causing a break to occur.
What 4 factors affect when shearing can be completed?
- Labor availability.
- Lamb survivability.
- Shed space.
- Weather concerns.
What do sheep that are prepared for shearing look like?
Dry and placed in a clean, vegetable matter free pen 12 hours prior to shearing in designated shearing groups.
How many hours should sheep be kept off feed and water pre-shearing?
6-12 hours.
Provide 3 reasons sheep are kept off of feed and water pre-shearing?
- Helps prevent cuts.
- Keeps sheep quieter and more comfortable during shearing.
- Reduced stomach fill.
What is needed in the shearing area for quality wool production?
- A raised shearing platform and tarps to maintain cleanliness.
- Adequate space (At least 5’ x 5’).
- Sheep holding area for easy catching and separation of the shorn v. unshorn.
What kind of holding areas, chutes, and alleyways do you use in sheep facilities?
Clean, dry, bedding free.
What is the best type of flooring to have in sheep facilities?
Solid, non-slick floors.
How often should shearing equipment be cleaned and disinfected?
Between flocks.
What is removing tags and bellies?
Removing large, dungy locks and inferior wool that grow on the belly.
What is skirting?
Removing off sorts from the fleece.
What is classing?
Allocating of the fleece to any particular standard quality, according to diameter, length, yield, etc. .
What is the procedure post-shearing?
- Treat any cuts with antiseptic.
- Treat cuts with fly repellent in warm weather.
- Turn sheep into clean, dry areas.
- Provide shelter.
How is wool rolled to preserve quality?
Flesh side out from tail to shoulder.
What is the wool place in once rolled?
A clean, dry burlap, nylon, or plastic sack.
*Burlap is being phased out.
Why are feeder lambs sheared?
- To stay cleaner during feeding.
- Improves lamb performance.
