Selecting Your Sheep
There are several characteristics that have an affect on the value of wool but the most important ones include: fiber diameter, staple length, density and body surface area. There are three ways of describing fiber diameter. The first one and most recently used is the micron system. A micron is 1/25,400th of an inch long. The second and oldest form is the blood system which is characterized by determining the amount of the Merino breed that is in your sheep and then classifying the wool that way. Some of the classes for this system are Fine, 1/2 Blood, 3/8 Blood and 1/4 Blood. The final way of determining fiber diameter is spinning count. Spinning count relates diameter to the length of the yarn and weight of the wool top. This is described as Hanks of yarn per pound of wool. A Hank is 560 yards. The next characteristic in determining the value of wool is staple length. The longer the staple length the higher the value. Staple length is simply the length of the wool fiber as measured in inches or centimeters. Thirdly, Yield is determined by taking into account the density and body surface area. Yield is determined when you subtract the shrink out of a 100 pound bundle of wool. Shrink includes grease, insects, moisture and hay as well as anything else that might be foreign material that is in the wool. Crimp or waviness is also taken into account when determining the value of the wool. Wool with a tight crimp is said to be fine and loose crimped wool is termed 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 |