| Domestic sheep (Latin: Ovis orientalis) are even-toed ungulate (artiodactyla) mammals from the ovis genus of the Bovidae family. The domestication of sheep dates back deep into antiquity, more than 8 thousand years ago by human beings basically due to their dense wool and edible meat. At present, sheared sheep wool or fleece is used by human beings more than the wool of any other animal. Sheep meat, called “mutton”, is one of the major consumable products in many countries worldwide. Besides wool and meat, sheep are also bred for obtaining sheep milk, sheep cheese, cooking oil and fells (sheepskin). Lastly, sheep are used in scientific experiments the most well known representative of this is the lamb Dolly the first-ever cloned mammal. Assumptions prevail that sheep are ancestors of European (Ovis musimon) or Asian (Ovis orientalis) moufflons. In a narrow sense, domesticated female sheep are understood to be sheep whereas males are usually called rams. Young females, which did not attain sexual maturity, are called ewes and the young are called lambs.
Sheep breeding is a branch of animal husbandry, which is engaged in the breeding of sheep. Practices all over the world played an important role in the economy of many countries. Presently, it is being employed with huge popularity in China, Australia, Great Britain and Russia.
World sheep livestock:
In 2004
(in millions)
People’s Republic of China: 157.9
Australia: 101.3
India 62.5
Iran 54.0
Sudan 48.0
New Zealand 39.2
Great Britain 35.8
Republic of South Africa 25.3
Total in the world 1.059.810.132
Source:
UN Food and Agriculture Organization (FAO)
Domesticated sheep is an artiodactyl ruminant, which is very well recognized by spirally-branched out horns of the males and curly wool. In other wild kinds of rams and also in the ancestors of sheep, wool does not form into curls and the tail is much shorter. In some primitive sheep breeds the tail also can be of a smaller size, however long tails and the white color of the wool have appeared in animals only during the early stages of domestication. In skull structure the domesticated sheep differ from their wild relatives with narrow eye sockets and a smaller head size. As a rule, the horns are well developed in sheep (two, but sometimes four or more) but sometimes horns are absent in some breeds or horns are only on male sheep (rams). The sheep has strong legs and are well adapted for traveling long distances on a hilly terrain.
The size and weight of domesticated sheep strongly differs depending on the breed. The growth rate and weight of an adult animal, in many respects, depends on heredity and for this reason, the breeding selection is often made on the basis of these characteristics. Usually, adult females weigh 45-100kg whereas huge males weigh 70-160 kg. On the whole, the height at the shoulder is 55-100 cm and the body length — 60—110 cm. As in other representatives of ram types, “lachrymal fossa” is available in the domesticated sheep on the front side of the lachrymal bones beneath the internal corner of the eye hollows. “Lachrymal Fossa” is skin depressions, rich in sudoriferous sebaceous glands, the secretions of which collect in the form of a fat odorous secreted liquid. Similar depressions, called “ungulate glands” are present between the upper joints of both fingers. The secretion secreted by these glands also lends the characteristic smell to sheep.
Adult sheep have 32 teeth (tooth formula I:0/3 C:0/1 P:3/3 M:3/3). The cutting teeth are located at an obtuse angle to jaw — such a structure allows the animals to more effectively bite grass in comparison to other herbivores. Bicuspid and premolars together form wide surface at the back portion of the mouth – sheep chew grass using these teeth. The development of teeth occurs gradually: initial milk teeth and regular teeth start appearing after a year or 1 ˝ years and start to be replaced with constants, and all the process of change comes to an end only on the fourth year of a life.
All sheep possess good hearing and are sensitive to noise. The lateral position of the eyes and the horizontally extended pupils increase the coverage angle up to approximately 270° - 320° which allows animals to look back without turning the head (dense wool can reduce the coverage angle). However, spatial sight is not sufficiently developed in sheep — shadows and pits in the ground can put the brakes on the movement of the animals. On the whole, sheep avoid shadow areas and prefer open and well illuminated places.
The horns are well developed in the majority of male breeds — they are spirally twisted with terminations outside and lateral protuberances. Even female animals have small sized horns. The color varies depending on the breed — from milky-white to dark-brown and black. Sheep with thin wool are usually white. Sheep with coarse wool has two layers of wool —first, the downy under-fur consists of fine fibers with a diameter of about 25 microns and the second layer of more massive fibers with a diameter of up to 100—200 microns. In fine-fleeced sheep, the wool consists only of the first layer. The length of the fibers constitute from 5—9 cm in fine-fleeced breeds and up to 10—15 cm in coarse wool animals.
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