Wool Grading by the American Blood Count System

Once upon a time - a long time ago - farmers (shepherds) were out standing in the field trying to compare one flock with another. They could all agree upon what a Merino fleece looked like: it was about 2 1/2 inches long and the fiber diameter was very fine and the crimp (that waviness in the fiber) was very small and close together. They decided that since everybody knew what a Merino fleece looked like, that it would be the standard for comparision and it would be called "Fine" (meaning the fiber diameter, not anything to do with quality).

Well, if you bred a Merino to some other non-Merino sheep the offspring would be half Merino, and you would expect that lamb's wool to have half the character of the Merino fleece. Further, since most other sheep have longer, coarser wool than Merinos do, you would expect that half of the character of that lamb's wool would also be longer and coarser. So, what you would get is called a 1/2 blood fleece and you would expect it to have a larger fiber diameter than Merino wool, a somewhat larger crimp, and a staple length of about 3 to 3 1/2 inches.

Then, if you crossed that half blood lamb with another sheep the offsring's wool would be called a 3/8ths blood fleece, and so on. The seven grades of wool, by the blood system are:

Fine Wool 2 1/2 inches in staple length Very fine crimp (close together)
1/2 Blood Wool 3 inches in staple length Meduim fine crimp
3/8ths Blood Wool 3 1/2 inches in staple length Medium crimp
1/4 Blood Wool 4 inches in staple length Medium coarse crimp
Low 1/4 Wool 4 1/2 inches in staple length Coarse crimp (large waves)
Common 5 inches in staple length Very coarse
Braid 6 inches in staple length The most coarse

This is not to say that all sheep today contain Merino blood. This system is merely used as a comparative system. In fact, the Corriedale breed was originally a cross between Merinos and Lincolns (a very lustrous, long, coarse wool breed). The desired result was a sheep which produced a 1/2 blood fleece with at least a 4 inch staple. This wool was especially desirable in the "sweater trade", because yarn spun from it was both soft and strong.

One of the surprises of breeding sheep is what will the wool look like? That is why a lot of breeders stick to a particular breed of sheep - you can expect certain wool qualities. However, there is that occasional individual who seems to get more of one ancestor's qualities than an equal share. That individual whose fleece is a lot finer than it should be or a lot coarser than you hoped for.

Perhaps you have heard of the English (Bradford) Spinning Count System. This originated in the 19th century (along with mechanized spinning equipment). It is the number of hanks of yarn, each 560 yards in length, that it is possible to spin from one pound of clean wool. The finer the wool fiber, the more hanks (greater length, thinner yarn) that can be obtained from one pound.

Or, perhaps you have heard of the latest and greatest: the Micron System. For this you need a microscope and a background slide with micron crosshairs for comparison.

Fine Wool 64 to 70 to 80 Hanks Less than 22.04 Microns
1/2 Blood 60 to 62 Hanks 22.05 to 24.94 Microns
3/8 Blood 56 to 58 Hanks 24.95 to 27.84 Microns
1/4 Blood 50 to 54 Hanks 27.85 to 30.99 Microns
Low 1/4 46 to 48 Hanks 31.00 to 34.39 Microns
Common 44 to 40 Hanks 34.40 to 36.19 Microns
Braid 40 to 36 Hanks 36.20 to 40.20 Microns

(The information in this table is taken from information published by Dr. Glen Spurlock and Dr. Vern B. Swanson, CSU Cooperative Extension Bulletin) Following is a table which compares the different sheep breeds and the wool they produce. Note, there are only Wool breeds listed. There is no information on Hair breeds. Also please notice that some breeds have a very large range of fleece grades within the breed. This means two things: there can be a great difference individual to individual, and that genetically there can be more variables in fleece to work with. As in trying to purchase purebred breeding stock: the buyer would have to look very closely at the individual sheep to decide if that animal had the fleece qualitites desired.

Delaine Merino 80's Down to 64's 18 to 22 Microns
Rambouillet 70's Down to 60's 19 to 25 Microns
New Zealand Merino 64's Down to 60's 20 to 25 Microns
Targhee & Romeldale 62's Down to 58's 22 to 26 Microns
Corriedale & Columbia 62's Down to 46's 22 to 34 Microns
Southdown 60's Down to 50's 24 to 31 Microns
Blue Leicester60's Down to 56's 24 to 28 Microns
Shropshire, Suffolk, Dorset Horn, Montadale 58's Down to 50's 25 to 31 Microns
Finish Landrace (Finns) & Cheviot58's Down to 48's 25 to 32 Microns
Oxford50's Down to 46's 29 to 34 Microns
Romney 48's Down to 44's31 to 36 Microns
Border Leicester46's Down to 40's33 to 38 Microns
Lincoln & Cotswold40's Down to 36's 37 to 40 Microns

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