Sheep
| Sheep | |
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| Romney sheep (More) | |
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| Species: | O. aries
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| Binomial name | |
| Ovis aries | |
The Domestic Sheep (Ovis aries) is the most common species of the sheep genus. As such it is a woolly ruminant quadruped which probably descends from the wild moufflon of south-central and south-west Asia.
Sheep breeders refer to female sheep as ewes, intact males as rams, castrated males as wethers, yearlings as hoggets, and younger sheep as lambs. Note the adjective applying to sheep: ovine; and the collective terms for sheep: flock and mob. The term herd is also occasionally used in this sense.
Many breeds of sheep occur, generally sub-classable as: woolclass breeds, hair class breeds.
Farmers develop wool breeds for superior wool quantity and quality (fineness of fibers), wool staple length and degree of crimp in the fiber. Major wool breeds include Merino, Rambouillet, and Lincoln.
Breeders of dual purpose wool class sheep concentrate on fast growth, multiple births, ease of lambing, and hardiness. Breeds of meat sheep include Suffolk, Hampshire, Dorset, Columbia, and Texel.
One dual-use breed is the Corriedale. Sometimes sheep are used for both purposes equally and cross-breeding is practiced to maximise both outputs. For example, Merino ewes providing wool may be crossed with Suffolk rams to produce lambs which are robust and suitable for the meat market. The Finnish Landrace sheep has a reputation for multiple births.
Hair class sheep are the original class of sheep in the world, developed for meat and leather. They are prolific, highly disease and parasite resistant generally. Dorpers and Kahtahdins are composite breeds of wool and hair crosses with different degrees of wool/hair mixes within the hair class. True hair sheep, are those breeds such as St. Croix, Blackbellie Barbado, Mouflon, Santa Inez and Royal White eg. that shed their protective down fiber to an all hair coat in the Spring/Summer. Hair class sheep are becoming more popular for their no shear aspects.
Cultural significance
For centuries, sheep have had associations with many cultures, especially in the Mediterranean area and Wales, where they form the most common type of livestock in pastoralism. Selective breeding of sheep has frequently occurred.
A wide symbology relates to sheep in ancient art, traditions and culture. Judaism uses many sheep references including the Passover lamb. Christianity uses sheep-related images, such as: Christ as the good shepherd, or as the sacrificed Lamb of God (Agnus Dei); the bishop's Pastoral; the lion lying down with the lamb. Greek Easter celebrations traditionally feature a meal of Paschal lamb. Sheep also have considerable importance in Arab culture.
Herding sheep plays an important historico-symbolic part in the Jewish and Christian faiths, since Abraham, Jacob, Moses, and King David all worked as shepherds.
The ram is the first sign of the Western zodiac, in which it is known as Aries. The sheep (or goat) also forms one of the animals associated with the 12-year cycle of in the Chinese zodiac, related to the Chinese calendar. Chinese tradition associates each animal with certain personality traits. See: Sheep (Zodiac).
The growing of sheep for wool and meat became a major industry in post-colonial Australia and New Zealand which has remained to this day. As a result, sheep and sheep shearing have become an important part of the folklore and cultural tradition of these two countries.
In George Orwell's satirical novel Animal Farm, sheep are used to represent the ignorant and uneducated masses of revolutionary Russia. The sheep are unable to be taught the subtleties of revolutionary ideology and can only be taught repetitive slogans such as "Four legs good, two legs bad" which they bleat in unison at rallies. This is due to the widespread perception that sheep lack intelligence and also their undoubted herd mentality.
Economic importance
Raising sheep occupied many farmers in ancient economies, given that this animal can give milk (and all its derivative products, such as cheese), wool, sheepskin (used for making footwear, rugs and other coverings) and meat. In the 21st century, sheep retain considerable importance in the economies of several countries. After China, the largest producers of sheep are in the southern hemisphere: Australia, New Zealand and the Patagonian regions of Argentina, Uruguay and Chile.
| Global Sheep & Lamb production - 2003 (million head) | |
|---|---|
 People's Republic of China |
143.8 |
 European Union |
106.6 |
 Australia |
99.5 |
 India |
58.0 |
| former Soviet Union | 49.0 |
 New Zealand |
39.3 |
 Canada and  United States |
17.7 |
| Eastern Europe | 17.2 |
 Brazil |
14.2 |
 Colombia |
12.5 |
| All Other | 515.2 |
| Total | 1,073.0 |
| Source: UN Food & Agriculture Organisation (FAO) | |
In some places, like Sardinia, sheep-breeding has become the principal and characteristic activity.
Even in the 21st century, sheep can provide a return on investment of up to 400% of their cost annually (including reproduction gains). Sheep breeding has played a role in several historic conflicts, such as the Highland clearances, the U.S. range wars, and the English "inclosing of the commons".
Domestication
Domestic sheep are descended from the moufflon (Ovis orientalis) that is found from the mountains of Turkey to southern Iran. Evidence for domestication dates to 9000 BCE in Iraq.[1] It has been found by DNA analysis to be one of two ancestors of domestic sheep. Although the second ancestor has not been identified, both the urial and argali have been ruled out. The urial (O. vignei) is found from northeastern Iran to northwestern India. It has a higher number of chromosomes (58) than domestic sheep (54) which makes it an unlikely ancestor of the latter, but it interbreeds with the moufflon. The argali sheep (O. ammon) of inner Asia (Tibet, Himalayas, Altai, Tien-Shan and Pamir) has 56 chromosomes and the Siberian snow sheep (Ovis nivicola) with 52 chromosomes.
The European moufflon (O. musimon) found on Corsica and Sardinia as well as the Cretan and the extinct Cypriot wild sheep are probably descended from early domestic sheep that turned feral. Evidence of early domesticated sheep have been found in PPNB Jericho and Zawi Chemi Shanidar. The fleece-bearing sheep is only found since the Bronze Age. Primitive breeds, like the Scottish Soay sheep have to be plucked (a process called rooing), instead of sheared, as the kemps are still longer than the soft fleece, or the fleece must be collected from the field after it falls out.
Cuisine
Chefs and diners commonly know sheep meat prepared for food as lamb or mutton (compare the French word for "sheep": mouton).
Ewes' milk is used in the production of cheese and yogurt in many upland parts of the world. Well known sheepmilk cheeses include the roquefort and brocciu of France, the pecorino of Italy and the feta cheese of Greece.
Behavior
Some breeds of sheep exhibit a strong flocking behaviour. This was used as an example to Israelites in the Christian bible to instruct them to obey their shepherd, or master. Flocking behaviour is advantageous to non-predatory animals; the strongest animals fight their way to the center of the flock which offers them great protection from predators. It can be disadvantageous when food sources are limited and sheep are almost as prone to overgrazing a pasture as goats. In Iceland, where sheep have no natural predators, and grasses grow slowly, none of the various breeds of sheep exhibit a strong flocking behaviour.
Sheep flocking behaviour is so prevalent in some English breeds that special names apply to the different roles sheep play in a flock. One calls a sheep that roams furthest away from the others an outlier, a term originally used to refer to someone who lives far from where they work. This sheep ventures further away from the safety of the flock to graze, due to a larger flight zone or a weakness that prevents it from obtaining enough forage when with the herd. Another sheep, the bellwether, leads the others. Traditionally this was a castrated Ram (or wether) with a bell hung off a string around its neck. The tendency to act as an outlier, bellwether or to fight for the middle of the flock stays with sheep throughout their adulthood; that is unless they have a scary experience which causes them to increase their flight zone.
Homosexuality in male sheep (found in 6–10% of rams) is associated with variations in cerebral mass distribution and chemical activity. A study reported in Endocrinology concluded that biological factors are in play; this study replicated similar findings in humans. It shows that approximately 10% of males are homosexual and that the brains of homosexual males are different. [2].
According to a spokesperson of the British National Sheep Association, "Sheep are quite intelligent creatures and have more brainpower than people are willing to give them credit for." [3] For example, sheep in Yorkshire, England found a way to get over cattle grids by rolling on their backs. A study published in National Geographic (December 8) showed a sheep can remember the faces of fifty other sheep for over two years.
Sheep can become hefted to one particular pasture so they do not roam far from home. Since the outbreak of foot and mouth disease in the United Kingdom, transplanted sheep have had to be trained to stay in their fields.
Glossary
This is a glossary of terms that relate to sheep and domestic sheep. Note that some terms have localised meanings which may be used only in one geographical region, or may mean slightly different things in different areas.
- Chevon — goat meat. A term used mainly in Eastern countries.
- Ewe — a female sheep, capable of producing lambs.
- Hoggett (or Hoggatt) — a sheep which by virtue of its age and development is no longer a lamb, but not yet mutton. esp. in relation to meat breeds.
- Lamb — a young sheep, generally unweaned. In many Eastern countries, there is a less strict definition of lamb which may include older hoggetts. Also used to refer specifically to the meat of such a sheep.
- Mutton — an older female sheep to be used for meat. Also used to refer specifically to the meat of such a sheep. May refer to goat meat in eastern countries. Derived from the French word Mouton (sheep).
- Ram (also called a tup) -- a male sheep.
- Old-season lamb — a lamb a year old or more.
- Ovine — member of the genus Ovis.
- Slink — a very young lamb.
- Sucker — an unweaned lamb.
- Wether — a castrated male sheep.
See also
- Blue tongue disease
- Dolly the sheep
- Lamb (food)
- List of sheep breeds
- Ric Dias
- Scrapie
- Sheep husbandry
- Sheep shearing
- Sheepskin
- Shepherd
- Wool
References
- ^ . ISBN 0-313-31342-3.
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External links
Books
- Juliet Clutton-Brocl. A natural history of domesticated animals (London 1987).
- Journal of Heredity. 1998 Mar-Apr;89(2):113-20. Analysis of mitochondrial DNA indicates that domestic sheep are derived from two different ancestral maternal sources: no evidence for contributions from urial and argali sheep. Hiendleder S, Mainz K, Plante Y, Lewalski H. Template:Link FA