Sheep And Cattle 1

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Sheep (Ovis aries) are quadrupedal, ruminant mammals typically kept as livestock. Like all ruminants, sheep are members of the order Artiodactyla, the even-toed ungulates. Although the name "sheep" applies to many species in the genus Ovis, in everyday usage it almost always refers to Ovis aries. Numbering a little over one billionSONY PCG-8113M battery, domestic sheep are also the most numerous species of sheep.

Sheep are most likely descended from the wild mouflon of Europe and Asia. One of the earliest animals to be domesticated for agricultural purposes, sheep are raised for fleece, meat (lamb, hogget or mutton) and milk. A sheep's wool is the most widely used animal fiber, and is usually harvested by shearingSONY PCG-8112M battery. Ovine meat is called lamb when from younger animals and mutton when from older ones. Sheep continue to be important for wool and meat today, and are also occasionally raised for pelts, as dairy animals, or as model organisms for science.

Sheep husbandry is practised throughout the majority of the inhabited world, and has been fundamental to many civilizationsSONY PCG-7134M battery . In the modern era, Australia, New Zealand, the southern and central South American nations, and the British Isles are most closely associated with sheep production.

Sheep-raising has a large lexicon of unique terms which vary considerably by region and dialect. Use of the word sheep began in Middle English as a derivation of the Old English word scēap; it is both the singular and plural name for the animalSONY PCG-7131M battery. A group of sheep is called a flock, herd or mob. Adult female sheep are referred to as ewes, intact males as rams or occasionally tups, castrated males as wethers, and younger sheep as lambs. Many other specific terms for the various life stages of sheep exist, generally related to lambing, shearing, and age.

Being a key animal in the history of farming, sheep have a deeply entrenched place in human culture, and find representation in much modern language and symbologySONY PCG-7122M battery . As livestock, sheep are most-often associated with pastoral, Arcadian imagery. Sheep figure in many mythologies—such as the Golden Fleece—and major religions, especially the Abrahamic traditions. In both ancient and modern religious ritual, sheep are used as sacrificial animals.

Description

A sheep's skull

Domestic sheep are relatively small ruminants, usually with a crimped hair called wool and often with horns forming a lateral spiralSONY PCG-7121M battery. Domestic sheep differ from their wild relatives and ancestors in several respects, having become uniquely neotenic as a result of selective breeding by humans. A few primitive breeds of sheep retain some of the characteristics of their wild cousins, such as short tails. Depending on breed, domestic sheep may have no horns at all (i.e. polled), or horns in both sexes, or in males only. Most horned breeds have a single pair, but a few breeds may have several. SONY PCG-7113M battery

Another trait unique to domestic sheep as compared to wild ovines is their wide variation in color. Wild sheep are largely variations of brown hues, and variation within species is extremely limited. Colors of domestic sheep range from pure white to dark chocolate brown and even spotted or piebald. Selection for easily dyeable white fleeces began early in sheep domesticationSONY PCG-7112M battery, and as white wool is a dominant trait it spread quickly. However, colored sheep do appear in many modern breeds, and may even appear as a recessive trait in white flocks.[4][5] While white wool is desirable for large commercial markets, there is a niche market for colored fleeces, mostly for handspinning.[6] The nature of the fleece varies widely among the breeds, from dense and highly crimpedSONY PCG-8Z3M battery , to long and hair-like. There is variation of wool type and quality even among members of the same flock, so wool classing is a step in the commercial processing of the fibre.

Suffolks are a medium wool, black-faced breed of meat sheep that make up 60% of the sheep population in the U.S.

Depending on breed, sheep show a range of heights and weights. Their rate of growth and mature weight is a heritable trait that is often selected for in breeding. SONY PCG-8Z2M battery  Ewes typically weigh between 45 and 100 kilograms (99 and 220 lb), and rams between 45 and 160 kilograms (99 and 350 lb).[8] When all deciduous teeth have erupted, the sheep has 20 teeth.[9] Mature sheep have 32 teeth. As with other ruminants, the front teeth in the lower jaw bite against a hard, toothless pad in the upper jaw. These are used to pick off vegetation, then the rear teeth grind it before it is swallowedSONY PCG-8Z1M battery . There are eight lower front teeth in ruminants, but there is some disagreement as to whether these are eight incisors, or six incisors and two incisor-shaped canines. This means that the dental formula for sheep is either  or  [10] There is a large toothless gap between the front "biting" teeth and the rear "grinding" teethSONY PCG-8Y3M battery.

For the first few years of life it is possible to calculate the age of sheep from their front teeth, as a pair of milk teeth is replaced by larger adult teeth each year, the full set of eight adult front teeth being complete at about four years of age. The front teeth are then gradually lost as sheep age, making it harder for them to feed and hindering the health and productivity of the animalSONY PCG-8Y2M battery. For this reason, domestic sheep on normal pasture begin to slowly decline from four years on, and the average life expectancy of a sheep is 10 to 12 years, though some sheep may live as long as 20 years.

Sheep have good hearing, and are sensitive to noise when being handled.[13] Sheep have horizontal slit-shaped pupils, possessing excellent peripheral vision; with visual fields of approximately 270° to 320°, sheep can see behind themselves without turning their heads. SONY PCG-7Z1M battery  Many breeds have only short hair on the face, and some have facial wool (if any) confined to the poll and or the area of the mandibular angle; the wide angles of peripheral vision apply to these breeds. A few breeds tend to have considerable wool on the face; for some individuals of these breeds, peripheral vision may be greatly reduced by "wool blindness", unless recently shorn about the face.SONY PCG-6W2M batterySheep have poor depth perception; shadows and dips in the ground may cause sheep to baulk. In general, sheep have a tendency to move out of the dark and into well-lit areas,[16] and prefer to move uphill when disturbed. Sheep also have an excellent sense of smell, and, like all species of their genus, have scent glands just in front of the eyes, and interdigitally on the feetSONY PCG-5J5M battery. The purpose of these glands is uncertain,[17] but those on the face may be used in breeding behaviors.[7] The foot glands might also be related to reproduction,[7] but alternative reasons, such as secretion of a waste product or a scent marker to help lost sheep find their flock, have also been proposed. SONY PCG-5K2M battery

Sheep compared to goats

Sheep and goats are closely related as both are in the subfamily Caprinae. However, they are separate species, so hybrids rarely occur, and are always infertile. A hybrid of a ewe and a buck (a male goat) is called a sheep-goat hybrid (only a single such animal has been confirmed), and is not to be confused with the genetic chimera called a geepSONY PCG-5K1M battery . Visual differences between sheep and goats include the beard and divided upper lip of goats. Sheep tails also hang down, even when short or docked, while the short tails of goats are held upwards. Sheep breeds are also often naturally polled (either in both sexes or just in the female), while naturally polled goats are rare (though many are polled artificially). Males of the two species differ in that buck goats acquire a unique and strong odor during the rutSONY PCG-5J4M battery, whereas rams do not.[12]

Breeds

Sheep being judged for adherence to their breed standard, and being held by the most common method of restraint

See also: List of sheep breeds

The domestic sheep is a multi-purpose animal, and the more than 200 breeds now in existence were created to serve these diverse purposes. Some sources give a count of a thousand or more breeds, but these numbers cannot be verified, according to some sources. However,several hundred breeds of sheep have been identified by the FAOSONY PCG-5J1M battery  (Food and Agriculture Organization of the UN), with the estimated number varying somewhat from time to time: e.g. 863 breeds as of 1993,[21] 1314 breeds as of 1995 and 1229 breeds as of 2006.[23] (These numbers exclude extinct breeds, which are also tallied by the FAO.) For purposes of such tallies, the FAO definition of a breed is "either a subspecific group of domestic livestock with definable and SONY PCG-5G2M battery  identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups within the same species or a group for which geographical and/or cultural separation from phenotypically similar groups has led to acceptance of its separate identity."[23] Almost all sheep are classified as being best suited to furnishing a certain product: wool, meat, milk, hides, or a combination in a dual-purpose breedSony VAIO PCG-8131M battery. Other features used when classifying sheep include face color (generally white or black), tail length, presence or lack of horns, and the topography for which the breed has been developed. This last point is especially stressed in the UK, where breeds are described as either upland (hill or mountain) or lowland breeds.[16] A sheep may also be of a fat-tailed type, which is a dual-purpose sheep common in Africa and Asia with larger deposits of fat within and around its tailSony VAIO PCG-8152M battery.

The Barbados Blackbelly is a hair sheep breed of Caribbean origin.

Breeds are often categorized by the type of their wool. Fine wool breeds are those that have wool of great crimp and density, which are preferred for textiles. Most of these were derived from Merino sheep, and the breed continues to dominate the world sheep industry. Downs breeds have wool between the extremes, and are typically fast-growing meat and ram breeds with dark faces. Sony VAIO PCG-31311M battery Some major medium wool breeds, such as the Corriedale, are dual-purpose crosses of long and fine-wooled breeds and were created for high-production commercial flocks. Long wool breeds are the largest of sheep, with long wool and a slow rate of growth. Long wool sheep are most valued for crossbreeding to improve the attributes of other sheep types. For exampleSony VAIO PCG-31111M battery: the American Columbia breed was developed by crossing Lincoln rams (a long wool breed) with fine-wooled Rambouillet ewes.

Coarse or carpet wool sheep are those with a medium to long length wool of characteristic coarseness. Breeds traditionally used for carpet wool show great variability, but the chief requirement is a wool that will not break down under heavy use (as would that of the finer breeds). As the demand for carpet-quality wool declinesSony VAIO PCG-8112M battery, some breeders of this type of sheep are attempting to use a few of these traditional breeds for alternative purposes. Others have always been primarily meat-class sheep.[25]

A minor class of sheep are the dairy breeds. Dual-purpose breeds that may primarily be meat or wool sheep are often used secondarily as milking animals, but there are a few breeds that are predominantly used for milkingSony VAIO PCG-7186M battery. These sheep do produce a higher quantity of milk and have slightly longer lactation curves.[26] In the quality of their milk, fat and protein content percentages of dairy sheep vary from non-dairy breeds but lactose content does not.[27]

A last group of sheep breeds is that of fur or hair sheep, which do not grow wool at all. Hair sheep are similar to the early domesticated sheep kept before woolly breeds were developed, and are raised for meat and peltsSony VAIO PCG-7171M battery. Some modern breeds of hair sheep, such as the Dorper, result from crosses between wool and hair breeds. For meat and hide producers, hair sheep are cheaper to keep, as they do not need shearing.[25] Hair sheep are also more resistant to parasites and hot weather.[12]

A sheep baa

A sheep bleat

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With the modern rise of corporate agribusiness and the decline of localized family farms, many breeds of sheep are in danger of extinction. The Rare Breeds Survival Trust of the UK lists 22 native breeds as having only 3,000 registered animals (each) Sony VAIO PCG-9Z1M battery, and the American Livestock Breeds Conservancy lists 14 as having fewer than 10,000. Preferences for breeds with uniform characteristics and fast growth have pushed heritage (or heirloom) breeds to the margins of the sheep industry.[25] Those that remain are maintained through the efforts of conservation organizations, breed registries, and individual farmers dedicated to their preservationSony VAIO PCG-5S1M battery.

Diet

A ewe grazing

Sheep are exclusively herbivorous mammals. Most breeds prefer to graze on grass and other short roughage, avoiding the taller woody parts of plants that goats readily consume.[31] Both sheep and goats use their lips and tongues to select parts of the plant that are easier to digest or higher in nutrition. Sony VAIO PCG-5P1M battery Sheep, however, graze well in monoculture pastures where most goats fare poorly.[31] 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 reticulumSony VAIO PCG-5N2M battery. The rumen is a 19 to 38-liter (5 to 10 gal) organ in which feed is fermented.[32] The fermenting organisms include bacteria, fungi, and protozoa.[33] (Other important rumen organisms include some archaea, which produce methane from carbon dioxide.[34]) The bolus is periodically regurgitated back to the mouth as cud for additional chewing and salivation. Sony VAIO PCG-3C2M batteryCud chewing is an adaptation allowing ruminants to graze more quickly in the morning, and then fully chew and digest feed later in the day.[35] This is safer than grazing, which requires lowering the head thus leaving the animal vulnerable to predators, while cud chewing does not.[12]

A sheep's ruminant system

During fermentation, the rumen produces gas that must be expelled; disturbances of the organ, such as sudden changes in a sheep's dietSony VAIO PCG-8161M battery, can cause the potentially fatal condition of bloat, when gas becomes trapped in the rumen, due to reflex closure of the caudal esophageal sphincter when in contact with foam or liquid.[36] After fermentation in the rumen, feed passes in to the reticulum and the omasum; special feeds such as grains may bypass the rumen altogetherSony VAIO PCG-8141M battery. After the first three chambers, food moves in to the abomasum for final digestion before processing by the intestines. The abomasum is the only one of the four chambers analogous to the human stomach (being the only one that absorbs nutrients for use as energy), and is sometimes called the "true stomach".Sony VAIO PCG-3J1M battery

Sheep follow a diurnal pattern of activity, feeding 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.[38] Types of land where sheep are raised vary widely, from pastures that are seeded and improved intentionally to rough, native landsSony VAIO PCG-3H1M battery. 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.[39]

Sheep graze on public land in Snake Valley, Utah.

Sheep are largely grazing herbivores, unlike browsing animals such as goats and deer that prefer taller foliage. With a much narrower face, sheep crop plants very close to the ground and can overgraze a pasture much faster than cattle.Sony VAIO PCG-3F1M battery For this reason, many shepherds use managed intensive rotational grazing, where a flock is rotated through multiple pastures, giving plants time to recover.[12][16] Paradoxically, sheep can both cause and solve the spread of invasive plant species. By disturbing the natural state of pasture, sheep and other livestock can pave the way for invasive plants. However, sheep also prefer to eat invasives such as cheatgrass
Sony VAIO PCG-3C1M battery
, leafy spurge, kudzu and spotted knapweed over native species such as sagebrush, making grazing sheep effective for conservation grazing.[40] Research conducted in Imperial County, California compared lamb grazing with herbicides for weed control in seedling alfalfa fields. Three trials demonstrated that grazing lambs were just as effective as herbicides in controlling winter weedsSony VAIO PCG-9Z2L battery. Entomologists also compared grazing lambs to insecticides for insect control in winter alfalfa. In this trial, lambs provided insect control as effectively as insecticides.[41]

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.[25] Also included in some sheep's diets are minerals, either in a trace mix or in licks.

Naturally, a constant source of potable water is also a fundamental requirement for sheepSony VAIO PCG-9Z1L battery. The amount of water needed by sheep fluctuates with the season and the type and quality of the food they consume.[42] When sheep feed on large amounts of new growth and there is precipitation (including dew, as sheep are dawn feeders), sheep need less water. When sheep are confined or are eating large amounts of cured hay, more water is typically needed. Sheep also require clean water, and may refuse to drink water that is covered in scum or algae.Sony VAIO PCG-9131L battery

Sheep are one of the few livestock animals raised for meat today that have never been widely raised in an intensive, confined animal feeding operation (CAFO).[6] Although there is a growing movement advocating alternative farming styles, a large percentage of beef cattle, pigs, and poultry are still produced under such conditions. Sony VAIO PCG-8161L batteryIn contrast, only some sheep are regularly given high-concentration grain feed, much less kept in confinement. Especially in industrialized countries, sheep producers may fatten market lambs before slaughter (called "finishing") in feedlots.[12] Many sheep breeders flush ewes and rams with a daily ration of grain during breeding to increase fertility.[43] Ewes are also flushed during pregnancy to increase birth weightsSony VAIO PCG-8152L battery, as 70% of a lamb's growth occurs in the last five to six weeks of gestation.[6] Otherwise, only lactating ewes and especially old or infirm sheep are commonly provided with grain.[6][25] Feed provided to sheep must be specially formulated, as most cattle, poultry, pig, and even some goat feeds contain levels of copper that are lethal to sheep.[6] The same danger applies to mineral supplements such as salt licks. Sony VAIO PCG-8141L battery

Behavior and intelligence

Sheep showing flocking behavior during a sheepdog trial

Sheep are prey animals with a strong gregarious instinct, and a majority of sheep behaviors can be understood in these terms. The dominance hierarchy of Ovis aries and its natural inclination to follow a leader to new pastures were the pivotal factors in it being one of the first domesticated livestock species. Sony VAIO PCG-8131L battery All sheep have a tendency to congregate close to other members of a flock, although this behavior varies with breed.[13] Farmers exploit this behavior to keep sheep together on unfenced pastures 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 also extremely food-orientedSony VAIO PCG-81312L battery, and association of humans with regular feeding often results in sheep soliciting people for food.[46] Those who are moving sheep may exploit this behavior by leading sheep with buckets of feed, rather than forcing their movements with herding.

In regions where sheep have no natural predators, none of the native breeds of sheep exhibit a strong flocking behavior. Sheep can also become hefted to one particular local pasture (heft) so they do not roam freely in unfenced landscapesSony VAIO PCG-81214L battery. Ewes teach the heft to their lambs, and if whole flocks are culled it must be retaught to the replacement animals.[7][49]

Escaped sheep being led back to pasture with the enticement of food. This method of moving sheep works best with smaller flocks.

Flock dynamics in sheep are, as a rule, only exhibited in a group of four or more sheep. Fewer sheep may not react as normally expected when alone or with few other sheep.[6] For sheep, the primary defense mechanism is simply to flee from danger when their flight zone is crossedSony VAIO PCG-81115L battery. Secondly, cornered sheep may charge or threaten to do so through hoof stamping and aggressive posture. This is particularly true for ewes with newborn lambs.[6]

In displaying flocking, sheep have a strong lead-follow tendency, and a leader often as not is simply the first sheep to move. However, sheep do establish a pecking order through physical displays of dominance. Dominant animals are inclined to be more aggressive with other sheep, and usually feed first at troughs. Sony VAIO PCG-81114L batteryPrimarily among rams, horn size is a factor in the flock hierarchy.[51] Rams with different size horns may be less inclined to fight to establish pecking order, while rams with similarly sized horns are more so.[51]

Sheep can become stressed when separated from their flock members.[7] Sheep can recognize individual human and ovine faces, and remember them for years. Relationships in flocks tend to be closest among related sheepSony VAIO PCG-81113L battery: in mixed-breed flocks same-breed subgroups tend to form, and a ewe and her direct descendants often move as a unit within large flocks.[6]

Sheep are frequently thought of as extremely unintelligent animals.[54] A sheep's herd mentality and quickness to flee and panic in the face of stress often make shepherding a difficult endeavor for the uninitiatedSony VAIO PCG-7142L battery. Despite these perceptions, a University of Illinois monograph on sheep found them to be just below pigs and on par with cattle in IQ,[6] and some sheep have shown problem-solving abilities; a flock in West Yorkshire, England allegedly found a way to get over cattle grids by rolling on their backs, although documentation of this has relied on anecdotal accounts. Sony VAIO PCG-7141L battery In addition to long-term facial recognition of individuals, sheep can also differentiate emotional states through facial characteristics.[52][53] If worked with patiently, sheep may learn their names, and many sheep are trained to be led by halter for showing and other purposes.[6] Sheep have also responded well to clicker training.[6] Very rarely, sheep are used as pack animals. Tibetan nomads distribute baggage equally throughout a flock as it is herded between living sites. Sony VAIO PCG-71111L battery

Reproduction

Main article: Domestic sheep reproduction

The second of twins being born on a New Zealand pasture

Sheep follow a similar reproductive strategy to other herd animals. A group of ewes is generally mated by a single ram, who has either been chosen by a breeder or has established dominance through physical contest with other rams (in feral populations).[25] Most sheep are seasonal breeders, although some are able to breed year-round.[25] Ewes generally reach sexual maturity at six to eight months of age, and rams generally at four to six months. Sony VAIO PCG-61411L battery However, there are exceptions. For example, Finnsheep ewe lambs may reach puberty as early as 3 to 4 months, and Merino ewes sometimes reach puberty at 18 to 20 months.[56] Ewes have estrus cycles about every 17 days,[57] during which they emit a scent and indicate readiness through physical displays towards rams. A minority of rams display a preference for homosexuality (8% on average) Sony VAIO PCG-61112L batteryand a small number of the females that were accompanied by a male fetus in utero are freemartins (female animals that are behaviorally masculine and lack functioning ovaries).

In feral sheep, rams may fight during the rut to determine which individuals may mate with ewes. Rams, especially unfamiliar ones, will also fight outside the breeding period to establish dominance; rams can kill one another if allowed to mix freely.[25] During the rut, even normally friendly rams may become aggressive towards humans due to increases in their hormone levels. Sony VAIO PCG-61111L battery

After mating, sheep have a gestation period of about five months,[63] and normal labor takes one to three hours.[64] Although some breeds regularly throw larger litters of lambs, most produce single or twin lambs. During or soon after labor, ewes and lambs may be confined to small lambing jugs,[66] small pens designed to aid both careful observation of ewes and to cement the bond between them and their lambsSony VAIO PCG-5T4L battery.

A lamb's first steps

Ovine obstetrics can be problematic. By selectively breeding ewes that produce multiple offspring with higher birth weights for generations, sheep producers have inadvertently caused some domestic sheep to have difficulty lambing; balancing ease of lambing with high productivity is one of the dilemmas of sheep breeding.[67] In the case of any such problems, those present at lambing may assist the ewe by extracting or repositioning lambs. Sony VAIO PCG-5T3L battery After the birth, ewes ideally break the amniotic sac (if it is not broken during labor), and begin licking clean the lamb.[25] Most lambs will begin standing within an hour of birth.[25] In normal situations, lambs nurse after standing, receiving vital colostrum milk. Lambs that either fail to nurse or that are rejected by the ewe require aid to live, such as bottle-feeding or fostering by another ewe. Sony VAIO PCG-5T2L battery

After lambs are several weeks old, lamb marking (the process of ear tagging, docking, and castrating) is carried out.[25] Vaccinations are usually carried out at this point as well. Ear tags with numbers are attached, or ear marks are applied for ease of later identification of sheep. Castration is performed on ram lambs not intended for breeding, although some shepherds choose to avoid the procedure for ethical, economic or practical reasons. Sony VAIO PCG-5S3L battery However, many would disagree with regard to timing. Docking and castration are commonly done after 24 hours (to avoid interference with maternal bonding and consumption of colostrum) and are often done not later than one week after birth, to minimize pain, stress, recovery time and complications The first course of vaccinations (commonly anti-clostridial) is commonly given at an age of about 10 to 12 weeksSony VAIO PCG-5S2L battery; i.e. when the concentration of maternal antibodies passively acquired via colostrum is expected to have fallen low enough to permit development of active immunity. Ewes are often re-vaccinated annually about 3 weeks before lambing, to provide high antibody concentrations in colostrum during the first several hours after lambing.[36] Ram lambs that will either be slaughtered or separated from ewes before sexual maturity are not usually castrated. Sony VAIO PCG-5S1L battery Tail docking is commonly done for welfare, having been shown to reduce risk of fly strike.[74] Objections to all these procedures have been raised by animal rights groups, but farmers defend them by saying they solve many practical and veterinary problems, and inflict only temporary painSony VAIO PCG-5R2L battery.

Health

A veterinarian draws blood to test for resistance to scrapie

Sheep may fall victim to poisons, infectious diseases, and physical injuries. As a prey species, a sheep's system is adapted to hide the obvious signs of illness, to prevent being targeted by predators.[7] However, some signs of ill health are obvious, with sick sheep eating little, vocalizing excessively, and being generally listless. Sony VAIO PCG-5R1L battery Throughout history, much of the money and labor of sheep husbandry has aimed to prevent sheep ailments. Historically, shepherds often created remedies by experimentation on the farm. In some developed countries, including the United States, sheep lack the economic importance for drug companies to perform expensive clinical trials required to approve more than a relatively limited number of drugs for ovine use. Sony VAIO PCG-5P4L batteryHowever, extra-label drug use in sheep production is permitted in many jurisdictions, subject to certain restrictions. In the US, for example, regulations governing extra-label drug use in animals are found in 21 CFR (Code of Federal Regulations) Part 530.[77] In the 20th and 21st centuries, a minority of sheep owners have turned to alternative treatments such as homeopathySony VAIO PCG-5P2L battery, herbalism and even traditional Chinese medicine to treat sheep veterinary problems.[6][7] Despite some favorable anecdotal evidence, the effectiveness of alternative veterinary medicine has been met with skepticism in scientific journals. The need for traditional anti-parasite drugs and antibiotics is widespread, and is the main impediment to certified organic farming with sheep. Sony VAIO PCG-5N4L battery

Many breeders take a variety of preventive measures to ward off problems. The first is to ensure all sheep are healthy when purchased. Many buyers avoid outlets known to be clearing houses for animals culled from healthy flocks as either sick or simply inferior.[7] This can also mean maintaining a closed flock, and quarantining new sheep for a monthSony VAIO PCG-5N2L battery. Two fundamental preventive programs are maintaining good nutrition and reducing stress in the sheep. Restraint, isolation, loud noises, novel situations, pain, heat, extreme cold, fatigue and other stressors can lead to secretion of cortisol, a stress hormone, in amounts that may indicate welfare problems. Excessive stress can compromise the immune system.[82] "Shipping fever" Sony VAIO PCG-51513L battery(pneumonic mannheimiosis, formerly called pasteurellosis) is a disease of particular concern, that can occur as a result of stress, notably during transport and (or) handling.[83][84] Pain, fear and several other stressors can cause secretion of epinephrine (adrenaline). Considerable epinephrine secretion in the final days before slaughter can adversely affect meat quality (by causing glycogenolysisSony VAIO PCG-51511L battery, removing the substrate for normal post-slaughter acidification of meat) and result in meat becoming more susceptible to colonization by spoilage bacteria.[80] Because of such issues, low-stress handling is essential in sheep management. Avoiding poisoning is also important; common poisons are pesticide sprays, inorganic fertilizer, motor oil, as well as radiator coolant containing ethylene glycolSony VAIO PCG-51412L battery.

A sheep infected with Orf, a disease transmittable to humans through skin contact

Common forms of preventive medication for sheep are vaccinations and treatments for parasites. Both external and internal parasites are the most prevalent malady in sheep, and are either fatal, or reduce the productivity of flocks.[7] Worms are the most common internal parasites. They are ingested during grazingSony VAIO PCG-51411L battery, incubate within the sheep, and are expelled through the digestive system (beginning the cycle again). Oral anti-parasitic medicines, known as drenches, are given to a flock to treat worms, sometimes after worm eggs in the feces has been counted to assess infestation levels. Afterwards, sheep may be moved to a new pasture to avoid ingesting the same parasites.[16] External sheep parasites include: lice (for different parts of the body) Sony VAIO PCG-51312L battery, sheep keds, nose bots, sheep itch mites, and maggots. Keds are blood-sucking parasites that cause general malnutrition and decreased productivity, but are not fatal. Maggots are those of the bot fly and the blow-fly. Fly maggots cause the extremely destructive condition of flystrike. Flies lay their eggs in wounds or wet, manure-soiled wool; when the maggots hatch they burrow into a sheep's fleshSony VAIO PCG-51311L battery, eventually causing death if untreated. In addition to other treatments, crutching (shearing wool from a sheep's rump) is a common preventive method. Nose bots are flies that inhabit a sheep's sinuses, causing breathing difficulties and discomfort. Common signs are a discharge from the nasal passage, sneezing, and frantic movement such as head shaking. External parasites may be controlled through the use of backliners, sprays or immersive sheep dips. Sony VAIO PCG-51211L battery

A wide array of bacterial and viral diseases affect sheep. Diseases of the hoof, such as foot rot and foot scald may occur, and are treated with footbaths and other remedies. These painful conditions cause lameness and hinder feeding. Ovine Johne's disease is a wasting disease that affects young sheep. Bluetongue disease is an insect-borne illness causing fever and inflammation of the mucous membranesSony VAIO PCG-41112L battery. Ovine rinderpest (or peste des petits ruminants) is a highly contagious and often fatal viral disease affecting sheep and goats.

A few sheep conditions are transmissible to humans. Orf (also known as scabby mouth, contagious ecthyma or soremouth) is a skin disease leaving lesions that is transmitted through skin-to-skin contact. Cutaneous anthrax is also called woolsorter's diseaseSony VAIO PCG-3A4L battery, as the spores can be transmitted in unwashed wool. More seriously, the organisms that can cause spontaneous enzootic abortion in sheep are easily transmitted to pregnant women. Also of concern are the prion disease scrapie and the virus that causes foot-and-mouth disease (FMD), as both can devastate flocks. The latter poses a slight risk to humans. During the 2001 FMD pandemic in the UKSony VAIO PCG-3A3L battery, hundreds of sheep were culled and some rare British breeds were at risk of extinction due to this.

Predation

Main article: Domestic sheep predation

A lamb being attacked by coyotes with the most typical method, a bite to the throat

Other than parasites and disease, predation is a threat to sheep and the profitability of sheep raising. Sheep have little ability to defend themselves, compared with other species kept as livestockSony VAIO PCG-3A2L battery. Even if sheep survive an attack, they may die from their injuries, or simply from panic.[7] However, the impact of predation varies dramatically with region. In Africa, Australia, the Americas, and parts of Europe and Asia predators are a serious problem. In the United States, for instance, over one third of sheep deaths in 2004 were caused by predation.[86] In contrast, other nations are virtually devoid of sheep predators, particularly islands known for extensive sheep husbandry. Sony VAIO PCG-3A1L battery Worldwide, canids—including the domestic dog—are responsible for most sheep deaths. Other animals that occasionally prey on sheep include: felines, bears, birds of prey, ravens and feral hogs.

Sheep producers have used a wide variety of measures to combat predation. Pre-modern shepherds used their own presence, livestock guardian dogs, and protective structures such as barns and fencing. Fencing (both regular and electric) Sony VAIO PCG-394L battery, penning sheep at night and lambing indoors all continue to be widely used.[25] More modern shepherds used guns, traps, and poisons to kill predators,[91] causing significant decreases in predator populations. In the wake of the environmental and conservation movements, the use of these methods now usually falls under the purview of specially designated government agencies in most developed countries . Sony VAIO PCG-393L battery

The 1970s saw a resurgence in the use of livestock guardian dogs and the development of new methods of predator control by sheep producers, many of them non-lethal.[16] Donkeys and guard llamas have been used since the 1980s in sheep operations, using the same basic principle as livestock guardian dogs.[7] Interspecific pasturing, usually with larger livestock such as cattle or horsesSony VAIO PCG-391L battery, may help to deter predators, even if such species do not actively guard sheep.[25] In addition to animal guardians, contemporary sheep operations may use non-lethal predator deterrents such as motion-activated lights and noisy alarms.[7]

Economic importance

Sheep are an important part of the global agricultural economy. However, their once-vital status has been largely replaced by other livestock species, especially the pig, chicken, and cow.[16] China, Australia, India, and Iran have the largest modern flocksSony VAIO PCG-384L battery, and serve both local and exportation needs for wool and mutton.[93] Other countries such as New Zealand have smaller flocks but retain a large international economic impact due to their export of sheep products. Sheep also play a major role in many local economies, which may be niche markets focused on organic or sustainable agriculture and local food customers. Sony VAIO PCG-383L battery Especially in developing countries, such flocks may be a part of subsistence agriculture rather than a system of trade. Sheep themselves may be a medium of trade in barter economies.[6]

Domestic sheep provide a wide array of raw materials. Wool was one of the first textiles, although in the late 20th century wool prices began to fall dramatically as the result of the popularity and cheap prices for synthetic fabrics.Sony VAIO PCG-382L battery For many sheep owners, the cost of shearing is greater than the possible profit from the fleece, making subsisting on wool production alone practically impossible without farm subsidies.[6] Fleeces are used as material in making alternative products such as wool insulation.[95] In the 21st century, the sale of meat is the most profitable enterprise in the sheep industry, even though far less sheep meat is consumed than chicken, pork or beef.Sony VAIO PCG-381L battery

Sheepskin is likewise used for making clothes, footwear, rugs, and other products. Byproducts from the slaughter of sheep are also of value: sheep tallow can be used in candle and soap making, sheep bone and cartilage has been used to furnish carved items such as dice and buttons as well as rendered glue and gelatin.[96] Sheep intestine can be formed into sausage casingsSony VAIO PCG-7185L battery, and lamb intestine has been formed into surgical sutures, as well as strings for musical instruments and tennis rackets.[3] Sheep droppings, which are high in cellulose, have even been sterilized and mixed with traditional pulp materials to make paper.[97] Of all sheep byproducts, perhaps the most valuable is lanolin: the water-proof, fatty substance found naturally in sheep's wool and used as a base for innumerable cosmetics and other products. Sony VAIO PCG-7184L battery

Some farmers who keep sheep also make a profit from live sheep. Providing lambs for youth programs such as 4-H and competition at agricultural shows is often a dependable avenue for the sale of sheep.[98] Farmers may also choose to focus on a particular breed of sheep in order to sell registered purebred animals, as well as provide a ram rental service for breeding. Sony VAIO PCG-7183L battery The most valuable sheep ever sold to date was a purebred Texel ram that fetched £231,000 at auction. The previous record holder was a Merino ram sold for £205,000 in 1989.[100] A new option for deriving profit from live sheep is the rental of flocks for grazing; these "mowing services" are hired in order to keep unwanted vegetation down in public spaces and to lessen fire hazard. Sony VAIO PCG-7182L battery

Despite the falling demand and price for sheep products in many markets, sheep have distinct economic advantages when compared with other livestock. They do not require the expensive housing, such as that used in the intensive farming of chickens or pigs. They are an efficient use of land; roughly six sheep can be kept on the amount that would suffice for a single cow or horseSony VAIO PCG-7181L battery. Sheep can also consume plants, such as noxious weeds, that most other animals will not touch, and produce more young at a faster rate.[104] Also, in contrast to most livestock species, the cost of raising sheep is not necessarily tied to the price of feed crops such as grain, soybeans and corn.[105] Combined with the lower cost of quality sheep, all these factors combine to equal a lower overhead for sheep producers, thus entailing a higher profitability potential for the small farmer. Sony VAIO PCG-7174L batterySheep are especially beneficial for independent producers, including family farms with limited resources, as the sheep industry is one of the few types of animal agriculture that has not been vertically integrated by agribusiness.[106]

Food

Shoulder of lamb

Main articles: Lamb and mutton and Sheep milk

See also: Category:Sheep's-milk cheeses

Sheep meat and milk were one of the earliest staple proteins consumed by human civilization after the transition from hunting and gathering to agriculture. Sony VAIO PCG-7173L batterySheep meat prepared for food is known as either mutton or lamb. "Mutton" is derived from the Old French moton, which was the word for sheep used by the Anglo-Norman rulers of much of the British Isles in the Middle Ages. This became the name for sheep meat in English, while the Old English word sceap was kept for the live animal.[107] Throughout modern historySony VAIO PCG-7172L battery, "mutton" has been limited to the meat of mature sheep usually at least two years of age; "lamb" is used for that of immature sheep less than a year.

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