C20: Wool producing sheep breeds, structure and characteristics of wool, wool defects

Question 1

What are the important production traits of sheep wool?

Answer 1

–> Fine apparel wool and fur (highly heritable, 0.4-
0.8).

–> Grease fleece weight (4-8 kg/shearing, once a
year).

–> Wool (clean fleece weight) (2-5 kg, most
important, rendement, 28-70 %,17 % humidity)
Wool-density (10-100/mm2).

–> S/P ratio (1:3-25).

–> Staple (combing fibre) length (5-15cm).

–> Crimps/unit length (spinning ability).

–> Fineness: fibre length and diameter µm (20-33
microns), evenness.

–> Medullation

–> Face covering ( wool blind, open faces).

–> Wrinkles or skin folds (neck, face, body).

–> Fibre (hair medullated) length and diameter (40-60 µm, microns, coarse, carpet wool).

–> Curl type and size (of Karakul, fur/pelt
production shortly after birth few days).

–> Wool production of Kashmere and Angora goats (mohair, pashmina).

Question 2

what are the characteristics of wool?

Answer 2

flies traits:
- Covering
- Folds
- Density
- Staple length
- Shearing weight
- Wool base yield
- Cleanness %

fibre traits:
- Fineness
- Crimping
- Fibre length
- Extensibility
- Tearing resistance
- EVENESS

Question 3

what are the advantages of wool?

Answer 3

• moisture and temperature regulating
• sustainability
• elasticity, shrinkage resistance
• fire resistance
• insulation,
• low environmental impact, biodegradable
• breathable
• repels dirt and stains, anti-static

Question 4

most popular sheep breeds worldwide for wool production.

Answer 4

rambouillet
corriedale
lincoln
merino
blue faced leicester
panama

Question 5

if a sheep goes too long without being shorn what problems can occur?

Answer 5

The excess wool impedes the ability of sheep to regulate their body temperatures. This can cause sheep to become overheated and die.

◦ Urine, feces and other materials become trapped in the wool, attracting flies, maggots and other pests.
This causes irritation, infections and endangers the health of the animal.

◦ Sheep with large amounts of wool can become immobilized by physical obstacles in their path
and are more susceptible to predator attacks.

Question 6

name 5 wool producers and the type of wool they produce

Answer 6

• Merino: Fine wool, N. Africa, fine wool quality Devin & Spain (used for clothing). Have Fine wool mutation → dominant 2 degree hair follicles and wool fibers.
• Wensleydale: Long wool, staple is 15 cm (year).
• Tsigai: Coarser wool/crossbred type wool, non-myelinated fibers.
• Romney Breed: This and Tsigai produce long fibers and produce fine wool.
• Racka: Coarse wool, Hungarian native, staple 30 cm. Strong medullated hair + finer undercoat.

mouflon: mixed wool –> hair and undercoat

• Devon

Question 7

how are breeds categorised?

Answer 7

Breeds are categorised by the type and quality of wool produced → fine- medium-, crossbred-, carpet (coarse)wool and fur type.

Question 8

characteristics of fine wool

Answer 8

Fine → have wool of great crimp and density which are prefered for textiles.
Most are derived from the Merino sheep.

Question 9

characteristics of medium wool

Answer 9

Medium → have wool between the 2 extremes.
Typically the fastest growing meat and ram breeds with dark faces.
Corriedale → dual purpose meat and wool breed.

Question 10

characteristics of long wool

Answer 10

Long wool → largest of the sheep with log wool and slow growth rate.

Valued for crossbreeding to improve the attributes of other sheep.

American columbia breed was developed by crossing Lincoln Rams (long wool) with Rambouillet (fine wool).

Question 11

characteristics of coarse wool

Answer 11

Coarse (carpet) → show great variability, but the main requirement is that the wool won’t break down under heavy use.
As their demand declines, many have been repurposed to meat producing sheep.

Question 12

Merino Breed Group:
what type of wool do they produce and why?

Answer 12

Origin: North Africa Barbary tribes but the fine wool quality was developed in Spain in the 16th-18th century.

Wool / fine wool producers.
Fine wool mutation → Dominant 2 degree hair follicles & wool fibers.
21-26 μm diameter.
super fine –14-18 μm diameter.

Rambouillet is part of the breed group (fine wool)

Question 13

other merino breed types and their uses

Answer 13

• Fine wool apparead in Europe in 16th century, where in Germany there were notable progressions made towards dual-purpose mutton and fine wool breeding until 18th century.
• From the 19th century → French Rambouillet types spread all around the world creating many local varieties.
• Cloth wool → Merino sheep (Electoral and NEgretti → ancient types).
• Combed fine wool merino breeds → ±20% of total population, mainly Rambouillet types/local breeds.
• Mutton Merino (meat & wool dual purpose):
  Leicester roses, Merino Precoce, German Meat
  Merino (Fleischschaf), Merino Landrace, South-African meat marino.
• Prolific: Merino Booroola (AUS) + cormo + dormer.
• Booroola (FecB): Merino strain that has a high rate of multiple births.
  Booroola’s prolificacy = studied extensively in New Zealand researchers who provided one of the
  1st examples of the practical application of gene mapping in sheep → by mapping the Booroola
  gene to chromosome 6.

Question 14

mention some wool defects

Answer 14

• Trichophagia: Wool eating in sheep → abomasal hair balls.
• Alopecia: Wool loss due to cold stress, mastitis, bad conditions, nutrition is bad, stomach diseases.
• Dermatitis: Inflammation in hair follicles and skin glands.
• Greyish and mat wool: Lack of CU, Co, Zn and vitamin A + osteomalacy. Bad wool quality.
• Dry wool: Less greasy, easy to pull out, lack of phosphorus, consequences of chronic parasitosis
  intoxication (EX: arsenic poisoning).
• Bad Wool Quality: Paratuberculosis, Flourine and molybdenum poisoning, as well as chronic parasitosis.
• Lighter streaks in pigmented wool: Sub-clinical chronic lack of Cu.