|Domestic sheep are a multi-purpose livestock. Sheep are raised for fleece, meat, and milk. There are more than 200 breed and there are over one billion domestic sheep in the world.|
Most people think Sheep are dumb, but they are wrong. Their flocking behavior and quickness to flee and panic can make shepherding a difficult endeavor for the uninitiated. Despite these perceptions, a University of Illinois study of sheep reported them to be just below pigs and on par with cattle in IQ. Sheep can recognize individual human faces, and remember them for years. In addition to long-term facial recognition of individuals, sheep can also differentiate emotional states through facial characteristics. If worked with patiently, sheep may learn their names and many sheep are trained to be led by halter for showing and other purposes. Sheep have also responded well to clicker training. It has been reported that some sheep have apparently shown problem-solving abilities; a flock in West Yorkshire, England allegedly found a way to get over cattle grids by rolling on their backs.
Mature sheep have 32 teeth. Front teeth are used to pick off vegetation then the rear teeth grind it before it is swallowed. There is a large gap between the incisors and the molars. The front teeth are then lost as sheep age, making it harder for them to feed. The average sheep lives up to 10 to 12 years old, though some sheep may live as long as 20 years.
Taste is the most important sense in sheep establishing forage preferences, with sweet and sour plants being preferred and bitter plants being more commonly rejected. Touch and sight are also important in relation to specific plant characteristics, such as succulence and growth form. Sheep have good hearing, and are sensitive to noise when being handled. Sheep also have an excellent sense of smell, and have scent glands just in front of the eyes, and between their toes.
Sheep have horizontal slit-shaped pupils, and have excellent peripheral vision, so good that they can see behind themselves without turning their heads. They are thought to have color vision and are able to distinguish between a number of colors: black, red, brown, green, yellow and white. They must lift their heads to see distant objects; this means that they are unable to judge depth accurately: shadows and dips in the ground may cause sheep to hesitate. Sight is a vital part of sheep communication and when grazing, they maintain visual contact with each other. Each sheep lifts its head upwards to check the position of other sheep in the flock. This constant monitoring is probably what keeps the sheep in a flock as they move along grazing.
Sheep are exclusively herbivores. Most breeds prefer to graze on grass and other short roughage, avoiding the taller woody parts of plants that goats readily consume. Like all ruminants, sheep have a complex digestive system composed of four chambers, allowing them to break down cellulose from stems, leaves, and seed hulls into simpler carbohydrates. When sheep graze, vegetation is chewed into a mass called a bolus, which is then passed into the rumen, via the reticulum. The rumen is a 19- to 38-liter (5 to 10 gal) organ in which feed is fermented. The fermenting organisms include bacteria, fungi, and protozoa. The bolus is periodically regurgitated back to the mouth as cud for additional chewing and salivation. Cud chewing allows sheep to graze more quickly in the morning, and then fully chew and digest feed later in the day. This is safer than grazing, which requires lowering the head for a long time thus leaving the animal vulnerable to predators.
Other than forage, the other staple feed for sheep is hay, often during the winter months. The ability to thrive solely on pasture (even without hay) varies with breed, but all sheep can survive on this diet. Also included in some sheep's diets are minerals, either in a trace mix or in licks.
Sheep feed from dawn to dusk, stopping sporadically to rest and chew their cud. Ideal pasture for sheep is not lawn like grass, but an array of grasses, legumes and forbs. Types of land where sheep are raised vary widely, from pastures that are seeded and improved intentionally to rough, native lands. Common plants toxic to sheep are present in most of the world, and include (but are not limited to) cherry, some oaks and acorns, tomato, yew, rhubarb, potato, and rhododendron.
Sheep are flock animals and strongly gregarious; much sheep behavior can be understood on the basis of these tendencies. Their natural inclination to follow a leader to new pastures was a pivotal factor in sheep being one of the first domesticated livestock species. All sheep have a tendency to congregate close to other members of a flock and sheep can become stressed when separated from their flock members. During flocking, sheep have a strong tendency to follow and a leader may simply be the first individual to move. Relationships in flocks tend to be closest among related sheep: in mixed-breed flocks, subgroups of the same breed tend to form, and a ewe and her direct descendants often move as a unit within large flocks. Sheep can become attached to one particular local pasture so they do not roam freely in unfenced landscapes. Flock behavior in sheep is generally only exhibited in groups of four or more sheep; fewer sheep may not react as expected when alone or with few other sheep.
Sheep do not defend territories. Their primary defense mechanism is to flee from danger. Cornered sheep may charge and butt, or threaten by hoof stamping and adopting an aggressive posture. This is particularly true for ewes with newborn lambs. Interestingly, in regions where sheep have no natural predators, none of the native breeds of sheep exhibit a strong flocking behavior.
Farmers exploit flocking behavior to keep sheep together on unfenced pastures such as hill farming, and to move them more easily. Shepherds may also use herding dogs in this effort, whose highly bred herding ability can assist in moving flocks. Sheep are food-oriented and association of humans with regular feeding often results in sheep soliciting people for food. Those who are moving sheep may exploit this behavior by leading sheep with buckets of feed, rather than forcing their movements with herding.
Sheep establish a dominance hierarchy through fighting, threats and competitiveness. Dominant animals are inclined to be more aggressive with other sheep, and usually feed first at troughs. Primarily among rams, horn size is a factor in the flock hierarchy. Rams with different size horns may be less inclined to fight to establish the dominance order, while rams with similarly sized horns are more so.
Domestic sheep are sometimes used in medical research. They are used for researching hypertension and heart failure. Pregnant sheep are as useful model for human pregnancy, and have been used to investigate the effects on fetal development of malnutrition and hypoxia. In behavioral sciences, sheep have been used in isolated cases for the study of facial recognition, as their mental process of recognition is qualitatively similar to humans.
|In 1996 Ian Wilmut, Keith Campbell and colleagues at the University of Edinburgh, Scotland, and the biotechnology company PPL Therapeutics, created cloned a sheep named Dolly (named after singer Dolly Parton). Dolly was the first mammal ever to be cloned from an adult cell. |
And in 2012, a transgenic sheep named "Peng Peng" was cloned by Chinese scientists, who spliced the sheep’s genes with that of a roundworm in order to increase production of fats healthier for human consumption.
Sheep come in the following colors:
- Brown (Moorit)
- Dark Brown
- Light Grey