Choosing the Right Sheep

 

 

 

 

 

 

 

The value of wool is based on fiber diameter, staple length, density, and body surface area.  Fiber diameter can be described using three different systems.  First, the blood system is the oldest system.  It was started in America when the amount of sheep in the country was low.  And of these low numbers, many were Merino.  So farmers started crossing their sheep with Merino sheep and then based their system off of the percent Merino blood in these new sheep.  The classifications are as follows:

  • Fine 
  • 1/2 Blood
  • 3/8 Blood
  • 1/4 Blood
  • Low 1/4
  • Common
  • Braid

The next classification is the spinning count.  This relates diameter to length of yarn and weight of wool top.  These values are described as Hanks of yarn produced per pound of clean wool.  A Hank is defined as 560 yards.  The third means of measuring fiber diameter is the micron system.  This is the most recent and most objective system.  A micron is defined as 1/25,400 of an inch. 

The following chart relates some values using all three systems.

Blood

Hank

Micron

Fine

64 - 80

17 - 22

1/2 Blood

60 - 62

22 - 25

3/8 Blood

56 - 58

25 - 28

1/4 Blood

50 - 54

28 - 31

The next characteristic to determine the value of wool is staple length.  This is simply the length of the wool fiber.  The longer the staple, the higher the worth of the wool.  These values are measured in inches or sometime centimeters.  The last two components of determining the quality of wool are included in the classification of yield, or shrink.  Yield is determined by taking 100lbs of raw wool and subtracting shrink.  Shrink includes grease, body salts, insects, hay, and moisture.  Yields can have a wide range with the average around 46-55%.  A final characteristic of wool is crimp.  This is the "waviness" of the wool.  For fine wool, the crimp will be tight.  This tightness makes the wool more attractive and has a greater elasticity.  When the crimp is loose, the wool is classified as coarse.

The following chart gives the fiber diameter, staple length, yield, and crimp of various wool breeds.

 
Breed Yield Fiber Diameter Staple Length Crimp
Classification
  % Microns Blood Hanks  Inches  
Cheviot 50 - 75 27 - 32 1/4 Blood 48's - 56's 5-Mar Medium coarse
Columbia 45 - 55 24 - 31 1/4 - 3/8 Blood 50's - 60's 3.5 - 5 Medium crimp
Corriedale 50 - 60 22 - 34 1/4 - 3/8 Blood 46's - 62's 3.5 - 6 Medium crimp
Merino 50 - 60 18 - 22 Fine Wool 64's - 80's 2.5 - 4 Very fine
Dorset 50 - 70 27 - 33 1/4 - 3/8 Blood 50's - 58's 2.5 - 4 Medium coarse
Finnsheep 50 - 60 25 - 32 1/4 Blood 48's - 58's 6-Mar Medium coarse
Lincoln 65 - 80 34 - 41 Braid 36's - 40's 6 Very coarse
Montadale 45 - 60 25 - 31 1/4 - 3/8 Blood 50's - 58's 3.25 - 4.5 Medium coarse
Oxford 50 - 62 30 - 34 Low 1/4 46's - 50's 5-Mar Coarse
Rambouillet 35 - 55 19 - 25 1/2 Blood 60's - 70's 2 - 4 Fine
Romney 65 - 80 31 - 38 Common 44's - 48's 5-Apr Coarse
Shropshire 50 - 75 25 - 34 1/4 - 3/8 Blood 50's - 58's 2.5 - 4 Medium coarse
Southdown 40 - 55 24 - 31 3/8 Blood 50's - 60's 1.5 - 2.5 Medium crimp
Suffolk 50 - 62 25 - 33 1/4 - 3/8 Blood 50's - 58's 2 - 3.5 Medium coarse
Targhee 50 - 55 22 - 26 3/8 - 1/2 Blood 58's - 62's 5-Mar Medium fine