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Yak

from Wikipedia, the free encyclopedia
Yak
Wildyak (Bos mutus)

Wild yak(Bos mutus)

System
without rank: Forehead weapon carrier (Pecora)
Family: Horned bearers (Bovidae)
Subfamily: Bovinae
Tribus: Cattle (Bovini)
Genre: Bovine animals(Bos)
Art: Yak
Scientific name
Bos mutus
(Przewalski, 1883)

The or yak(Bos mutus), also spelled yak, is a species of cattle common in High Asia. It is one of the five cattle species that have been domesticated (see domestic cattle). By a decision of the ICZN, since 2003 the more recent species name mutus (Latin for “dumb”), based on a specimen of the wild yak, has taken precedence over grunniens (“grunting”), based on the domestic form.[1]

Because of its grunt-like sounds, the yak is also called the (Tibetan) grunt o x. The name “yak” comes from the Tibetan language. In Tibetan, however, only the male animal is called གཡག་ g.yag (pronunciation: [

jáʔ]), while the female animal is called འབྲི ‘bri (pronunciation: [ɖì]).

While the domestic yak is widespread in large numbers in the Himalayas, Mongolia and even southern Siberia, the wild yak is threatened with extinction. Because of its adaptation to the extreme climatic conditions of its habitat, the yak continues to provide the livelihood of a large proportion of the people living in the Central Asian highlands and neighbouring countries. It provides milk, meat, leather, hair and wool. Its dung serves as fuel. The yak is still used as a beast of burden and mount. In an area of more than 1.4 million square kilometres, rural ways of life are predominantly only possible through yaks.[2]

Features

Physique

Yak bull

A yak bull can reach a head-torso length of 3.25 meters, a height at withers of 200 centimeters, and a weight of over one ton. Cows are much smaller and lighter. They reach a maximum withers height of 150 centimeters and weigh between 400 and 500 kilograms. Compared to a domestic cattle, the body of the yak is relatively long. Unlike domestic cattle, which have 13 pairs of ribs, the yak has 14 or 15 pairs of ribs.[3] As a result, the rib cage is broad and deep, which provides sufficient space for the strongly developed lungs and heart. The well-developed rib cage gives the yak a compact appearance despite its relatively elongated build.

Due to the elongated spinous processes of the cervical and thoracic vertebrae, the yak has a hump. This is somewhat more pronounced in males. The neck of males is also more muscular. The back line is slightly sloping in both sexes. This makes the hindquarters more flexible, which contributes to the yak’s surefootedness.[4]

In adaptation to climate, the yak’s flot mouth is very small. In particular, the upper lip is very mobile, allowing yaks to use much poorer pastures with lower vegetation than cattle.[5] The horns originate on the sides of the head and lead upward in an even curve. They grow up to one meter in length.[6] The udder of the cows, which has two pairs of teats, is very small and set high. The teats are only two to three inches long. The scrotum of the bulls is also close to the lower abdomen and is much smaller than that of a domestic cattle.[7][8]

Fur

Hausyakbulle, that shows many characteristics of the Wildyaks in the appearance.

The coat color of the wild yak varies from dark brown to black. The back as well as the flot mouth are usually somewhat lightened. The yak is the only cattle species that has a multi-layered coat. A distinction is made between a firmer top coat or long coat, a coarser wool and a fine, spinnable undercoat or fine wool.[9]

Except for the potty mouth and the teats embedded in the hair, all parts of the body are covered with dense hair. The foreskin of the penis is also covered with hair for protection against the cold. While the lower abdomen, the udder and the scrotum are only covered with short hairs, the hairs on the lower part of the body are very long and fall down as a so-called abdominal mane like a pelmet. The Yak appears decidedly short-legged through it. The tail is longhaired from the root. The long hairs on the chest, tail and belly of the Yak are also called horsehair, because they are similar to the hairs on the tail and mane of horses. However, they are much softer than those of horses.[10]

Coarse wool hairs, five to thirteen centimeters in length, are distributed over the entire body. As a third type of hair, fine wool is found in all body regions and accounts for over 80 percent of the hairiness.[11] In the abdominal region, for example, yaks have 220 coarse hairs and 800 fine wool hairs per square centimetre. During the shedding process, the yak loses mainly the woolly hair. The loss begins at the neck and continues at the back and belly region.[12]

Locomotion

Hausyakbulle

Yak hooves are relatively small and compact. They have sharp hoof tips and hard hoof edges. Due to the small hooves, they sink relatively deep into the ground, which helps them to slow down their forward momentum when moving downhill. They are basically very sure-footed when moving slowly and can cross swampy areas safely. If they sink too much in wet ground, they spread their legs and use the underside of their body to avoid sinking deeper. They then move on with swimming-like movements and thus show a different behaviour than, for example, horses, which in a comparable situation lash out in panic.[13]

Basically, yaks are very eager to move. Grazing yaks repeatedly take breaks in which they playfully chase each other with their tails raised. Their galloping movements resemble those of horses.[14] A sudden danger can lead to panic-like flight in yak herds. If their flight leads them downhill, there are occasional deaths from falls.[15]

Physiology

Adaptation to heat and cold

Yaks vary their respiratory rate depending on the outside temperature, among other factors. At high temperatures, respiration and pulse are high to dissipate excess heat and can then be three to four times that of cattle. Even at ambient temperatures above 13 degrees, respiratory rates increase. Above an ambient temperature of 16 degrees, heart rate and body temperature increase. When the ambient temperature reaches 20 degrees, yaks stay near water or in the shade. As a rule, they no longer eat, drink or ruminate and remain motionless in one place.[16]

At low outdoor temperatures, the breathing rate of yaks drops to seven to fifteen breaths per minute.[17] As a result, heat loss is relatively low.[18] They can tolerate ambient temperatures of -30 °C to -40 °C without any problems.[16] Sweat glands are found distributed over the entire body, but their functionality is considerably limited. In various tests, sweat secretion could only be found in the area of the muzzle. This characteristic also contributes to the increase in cold tolerance.[19]

Adjustment to the height

The low atmospheric pressure at high altitudes is not a limitation for yaks.[16] Due to the higher oxygen affinity of yak hemoglobin compared to cattle, they can absorb sufficient oxygen.[20]

Diseases and life expectancy

Yaks are susceptible to all the diseases that afflict other cattle species. These include anthrax, foot-and-mouth disease and tuberculosis, and at one time rinderpest.[21]
Yaks can reach an age of over 20 years in exceptional cases.

Distribution

Yaks find ideal living conditions in regions where the average temperature is below five degrees and does not exceed an average of 13 degrees during the warmest months of the year.

Original distribution of the wild yak

Hausyak in Ladakh

During the Younger Ice Age, wild yaks still occurred in a broad belt from the Aral Sea to Alaska.[22] The historical range included the Himalayas as well as large parts of the Chinese provinces of Xinjiang, Tibet and Qinghai and parts of southern Siberia. Wild yaks still lived in Tuva in the 14th century. In 1720 wild yaks were still reported near Kuznetsk, in 1739 in the Altai and Dauria.

Current population and threats

Maximum range of the wild yak

Today, wild yaks have disappeared from large areas of their former range, having migrated to the inhospitable high mountain areas as their range became more populated. They now live only in some parts of western China and Tibet. In 1994, there were still about 20,000 to 40,000 wild yaks in China.[23] Outside China, there are probably no wild yaks left. They are extinct in Nepal, and occurrences in Kashmir are apparently extinct.[24] There may still be some wild yaks in Ladakh, India. Except in Chinese zoos, wild yaks are not currently kept, only the Rostov-on-Don zoo is said to have had a single male in the 1970s.

Wild yaks have been classified as endangered(vulnerable) by the IUCN since 1996; previously they had been considered threatened until it was realised that there were many more wild yaks than previously thought, especially in the vastness of western China. Numbers were estimated at 15,000 at the time (8500 wild yaks in Tibet, 3700 in Qinghai and 2500 in Xinjiang), but may have declined somewhat since then.

In China, the species now belongs to the protected, non-huntable animal species of category 1. Despite this complete protection, wild yaks are still hunted. Other causes for the population decline are intermixing of wild and domesticated yaks as well as infection with cattle diseases.

Behavior

Nutrition

Yaks are ruminants that share many similarities with domestic cattle in their digestive physiology. Unlike domestic cattle, however, they are able to adapt quickly to changing forage conditions. They also build up a body reserve for the winter in adaptation to their habitat. The amount of feed required daily is less than that of so-called robust cattle such as Scottish Highland cattle.[25] They are also able to survive several days without food and water during snow storms.[26]

Hausyak in winter

The amount of feed consumed varies depending on the quality of the feed and thus the season. During the months of July to October, yaks consume about 5.6 kilograms of dry matter daily. The amount of forage decreases during the winter months and is lowest in March and April, when they eat an average of only 1.9 kilograms of dry matter per day.[26] Accordingly, seasonal weight changes are typical for yaks. During the winter months, bulls lose an average of 5.5 and yak cows 6.7 percent of their body weight. In extreme cases, they lose up to 20 percent of their body weight over the winter months.[27] They can only survive this weight loss if they have built up an adequate body reserve during the warm season.[26] Young cattle can withstand months of stagnant growth without suffering any lasting physiological damage.[28]

The alpine grass mats grazed by yaks are predominantly composed of Kobresia, a genus of sour grasses. These grasses tolerate and take advantage of high groundwater levels and short-term flooding with spring or surface water from the higher zones with perennial snow. Cobresia grasses are difficult for cattle to digest and ingest because of their short stature. The adaptation of yaks to these grasses rich in crude fibre is another reason why yaks dominate as domestic animals on the high plains of Central Asia.[29] Yaks can also ingest rough, spiny and woody plant parts.

For winter grazing, yaks use shrub willows and Artemisia shrubs at lower elevations. Until well into winter, however, cobresia grasses and sedges are available to the yaks, which do not die as quickly as sweet grasses at the onset of frost.[30]

Social behaviour

Yaks are social animals that stay close together during grazing. Outside the breeding season, these herds consist of yak cows and bulls that are not yet sexually mature. Bulls join herds only during the breeding period.[31]

Behaviour towards predators

They are extremely vigilant against predators such as wolves. It is known from domestic yak herds that in herds of 100 animals and more, only very rarely are individual animals killed by predatory mammals, as they defend themselves united against the predators. Cases of yak bulls killing wolves are regularly reported in Sichuan.[15] As a rule, individual animals are only killed by predatory mammals if they are separated from the herd during a panic flight.[15]

Reproduction

There are varying data on the time at which yaks reach sexual maturity. For bulls, data on the age at which they are sexually mature vary from one and a half to four years.[32] It is very likely that a number of external factors play a role in this, with the nutritional status of the yaks being of particular importance. Bulls show the highest reproductive readiness at an age of five to six years.[33] Bulls eight years and older are usually subject to younger bulls in rank fights, which is why they have little or no share in covering cows.[34]

Yak cows first show rutting symptoms at 12 months of age. However, most do not become pregnant until three years of age.[35] Yak cows reach their highest reproductive rate between five and nine years of age. Typically, a yak cow will give birth to four to five calves in her lifetime.[35] Cows older than 15 or 16 years very rarely give birth to calves.[36]

Good forage conditions are crucial for triggering the rut in cows. Usually, the rut falls in the period from June to September. However, an abundant food supply can also trigger the rut outside this period.[37] The mating is preceded by fierce rank fights between the bulls. Usually bulls dominate at six to seven years of age and cover the largest number of cows in a herd.[38] Cows usually only breed for 16 to 56 hours. They signal their readiness to mate by seeking the proximity of bulls and raising their tails. A cow in heat is constantly accompanied by the bull during her rut and is mated several times.

Styrian-bred Hausyak calf

The gestation period averages 257 days, which is about 30 days shorter than in domestic cattle. The calving season falls in the period from March to August and has its peak in April and May.[39] Shortly before birth, the yak cows separate from the herd. When labor begins, yaks often lie down, but during the birthing process they usually stand.[40] Newborn calves weigh between 9 and 16 kilograms, with cow calves usually being lighter than bull calves. The newborns can already stand after five to fifteen minutes and then look for the mother cow’s udder.[41]

Several reproductive characteristics of yaks are considered to be an adaptation to their specific habitat. The short gestation period compared to other cattle species and the resulting relatively low weight of the calves mean that yak cows are very mobile until immediately before giving birth and the birth is relatively quick. This is considered an advantage in a habitat where wolves could snatch an animal isolated from the herd.[14] However, the low birth weight reduces the young’s chances of survival during their first winter. Chinese scientists have also found that the higher the region in which cows live, the later the onset of the rut. Calves are therefore usually born during the season that is relatively warm and when the short growing season of the grasses has already begun.[14] Numerous yak cows also have only one estrus cycle per year. If they are not mated during this cycle, they cannot become pregnant again until the following year. This prevents calves from being born very late in the year and thus failing to reach the weight necessary for winter survival.[14]

System

Domestic yaks as beasts of burden, Nepal

The yak, as a ruminant and horn-bearer, is assigned to the subfamily of cattle and, within this subfamily, traditionally to the genus Actual Cattle. This genus is divided into the four subgenera Bos, Bibos, Poephagus and Novibos. While today’s cattle are descended from the aurochs and thus belong to the subgenus Bos, the yak is usually seen as a representative of the subgenus Poephagus. However, the debate about the taxonomic classification is still ongoing. According to recent studies, the bovids may be paraphyletic in relation to the bison, meaning that the yak may be more closely related to the two bison species bison and bison than to the other bovids. One indication of this relationship is the fact that between the nasal bones of the yak and the premaxilla lies the dorsal margin of the maxillae. This is usually the morphological indication that a species does not belong to the actual cattle, because in these the nasal bone touches the intermaxillary.[42] The yak is therefore sometimes placed in its own genus Poephagus.

Fossil evidence indicates that yak ancestors occurred in northeastern Eurasia during the late Tertiary. From the Pleistocene, fossil evidence is available for northern China, inner Mongolia, eastern Siberia, and northern Central Asia. It was not until the late Pleistocene that the Central Asian plateau rose to an altitude of over 4,500 metres above sea level. As a result, the original forests disappeared here and alpine pastures developed, on which wild yaks survived until modern times.[43]

Hausyak

Domestication

Decorated domesticated yak in front of the lake Yamzhog Yumco in Tibet

The date of domestication is disputed. Various theories place it at dates between 5000 B.C. and 1000 B.C. There are archaeological finds that indicate that a first domestication occurred in Tibet around 2,500 B.C..[44][45] This would roughly correspond to the time when the water buffalo was also domesticated and would thus have occurred about 4,000 years after the domestication of cattle. Prehistoric evidence indicates that the Qiang of the Nuomuhong culture kept yaks 3,000 years ago and made cloth, sacks, and rope from the hair of this species.[46] Nearly all ethnic groups for whom yak keeping is still significant today are closely related to the Qiang. The use of domestic yaks is also attested in ancient Chinese written sources.[47] These describe, among other things, that individual Qiang groups moved with their yak herds to other areas of the Central Asian plateau.[48] It is also certain that the yak was already a major supplier of meat, milk and wool in northwest China in the period 221 BC to 220 AD. There are a few regions where yak husbandry only gained importance in modern times. This applies, among others, to the region of the Tian Shan and Altai mountains. It was not until the 2nd half of the 19th century that about 100 yaks were introduced from Tibet to the Hejing area in the Tian shan Mountains. Yak husbandry spread from there to the Altai Mountains.[49]

Domestic yaks are simultaneously aggressive, wild, timid, and fearful, as well as distinct herd animals.[50] Individuals handling domestic yaks must take these characteristics into account. In Gen County, Xinjiang, 312 yaks died in four independent incidents due to falls on mountain slopes. Three of the four incidents were triggered by careless herding of the herd, causing the animals to panic and attempt to flee down the slope.[15] In most cases, herders keep a greater distance from grazing herds so as not to alarm them, and only intervene if wolves get close to the herds or they wander into grazing areas designated for other herds.[50]

To steer the herds, slingshots are mostly used, which are made of yak wool. Skilled herders are able to hit the yaks from a distance of more than 100 meters and thus steer them.[51] Domestic yaks are relatively easy to train to return to camp when called. Yak cows are trained as calves to have a collar put on them. This is used to restrain them when they are milked later.[52] However, there are always cows that are too wild and defend their calf too vigorously, so that they cannot be milked.[53] Although individual yaks also repeatedly allow themselves to be trained as pack, riding or draft animals, they are considered easier to lead when this is done in groups of ten or more.[15]

Features domesticated yaks

Domesticated yaks do not reach the dimensions of wild yaks. Bulls of domestic yaks have a withers height of 112 to 180 centimeters; cows are slightly smaller at 107 to 112 centimeters. Bulls reach a weight of 700 kilograms; cows weigh 250 to 350 kilograms. Domestic yaks can closely resemble wild yaks in appearance. However, they often have coat coloration that differs from wild yaks. In addition to brown and black yaks, there are also red, white or spotted yaks. Many domestic yaks do not have horns.

The variations between domestic and wild yak are indicative of domestication that has been taking place for a long time, as it is not assumed that selective breeding has taken place. The characteristics of domestic yaks, which include the smaller size, the shortened facial skull compared to the wild yak, as well as the partial hornlessness and the lightening of the coat, have not been deliberately bred out, but have occurred rather accidentally over time. Overall, the domestication of the domestic yak is not considered as advanced as that of domestic cattle.[54] Domestic yaks are often shy towards humans and tend to be aggressive. Especially yak cows with newborn calves show aggressive behaviour towards humans and go on the attack very quickly.[55]

Regions of today’s yak husbandry

Woman with Hausyak in Qinghai

The domestic yak has an economic importance only in Central Asia. The centres of yak husbandry are predominantly at altitudes above the tree line and in climatic zones where frost days occur throughout the year.[56] The country with the most yaks is China: in 1994, about 13.3 million domesticated yaks were kept there. Yak husbandry is concentrated in the provinces of Qinghai, Tibet and Sichuan. In Mongolia, about half a million yaks are kept. Yak husbandry is concentrated in the Changai, Altai and Chöwsgöl mountain regions. Because of the smaller population and the lower number of domestic animals kept, the economic importance that yaks have in Mongolia is greater than in China.[57] In 1989, nearly 76 percent of the yak herd was owned by state cooperatives. The largest herd, comprising about 20,000 animals, belonged to the Yalalt cooperative in the Tariat district of Arkhangai province. Since 1989, these cooperatives have been dissolved and all herds are now privately owned.[58]

In India, yaks are kept only in a relatively small area. The main focus is in the states of Jammu and Kashmir. The number of animals is estimated at about 30,000.[59] As the formerly common exchange of animals with Tibet has largely come to a standstill, inbreeding is an increasing problem, similar to Nepal and Bhutan. In India, attempts are being made to solve this problem by importing frozen yak semen from China and supporting yak farmers in exchanging male animals among themselves.[60]

In Bhutan, yaks are mainly kept by the Bhotia people, who migrated to Bhutan from Tibet several hundred years ago. These predominantly still live in a subsistence economy as mountain nomads. According to a census of livestock in 1992, about 30,000 yaks were kept in Bhutan.[61] About 90,000 yak and yak-domestic cattle crosses live on Nepalese soil. Their keepers are mainly Sherpas who also migrated to this region from Tibet. No current figures are available from Pakistan. For the year 1984, the number of pure-blooded yaks was estimated at 25,000.[62] On the other hand, it is unknown whether yaks are still kept in Afghanistan. On the territory of the former Soviet Union about 131,000 yaks were kept in 1991. Suitable holding areas can be found in Tajikistan, Kyrgyzstan and Kazakhstan.[63]

Occasionally domesticated yaks become feral again. For example, there are small herds of feral domestic yaks in Inner Mongolia, where there are no true wild yaks left. In regions where wild yaks occur, such domestic yaks are a threat to wild yak populations, as they interbreed with them and produce offspring that no longer have the characteristics of wild yaks.

Posture outside Asia

Hausyaks on the Koralpe, Styria

House yaks were first kept in Europe in 1785. Mostly this was limited to keeping in zoological gardens. Among those with a long tradition of keeping yaks is the English Whipsnade Wild Animal Park near Dunstables, which lies at an altitude of 150 above sea level. The park has been keeping and breeding yaks since 1944. During the warmer summer months, the animals mostly stay in the shade of trees. The only recurring health problem is copper deficiency, which does not occur in other cattle species kept in the park.[64]

Attempts to harness the special characteristics of this cattle in regions outside Central Asia first occurred in the 2nd half of the 19th century. In 1854, 12 yaks were introduced into France in order to use them to improve cattle farming in French mountainous areas. The experiments ended in 1862.[65] In Canada, between 1916 and 1921, attempts were made to create new breeds of cattle through cross-breeding with yaks, which would be suitable for keeping in northern Canada. Cross-breeding attempts were also made with bison and bison-cow hybrids.[66] All attempts were discontinued in 1928 because the hybrids did not prove to be sufficiently cold-resistant.[67]

Attempts to introduce the yak to the North Caucasus are considered more promising. There is a 260,000 hectare area of high mountain pasture there that is not currently used. The first attempts to introduce the yak here were made in 1971 and 1972, and these went relatively well.[68] The most famous yak herd in Europe is probably that of Reinhold Messner, who keeps a small herd of domestic yaks in Sulden on the Ortler.[69][70]

Yak breeds

A yak being loaded (Tibet 1939).

Domestication of the yak has not progressed very far. Targeted breeding was not common in the original nomadic economy and is limited, among other things, by the high aggressiveness of the bulls, which immediately react to disturbances with attacks during the mating season.[71] As a rule, between five and eight bulls are kept in a herd of about 100 cows. Rank wars between bulls determine how many cows a single bull covers. Surplus bulls are castrated at an age of 1 to 2.5 years.[72] Artificial insemination and a targeted mating of a specific bull with a cow has only gained importance in recent years.[73]

Phenotypic differences exist between individual populations despite the lack of selective breeding. These differences are almost exclusively due to the geographical separation of widely divergent locations. For example, the domestic yaks common in Mongolia are to a large extent hornless. This makes it easier to handle the animals and reduces the risk of injury in rank fights. However, it is by no means a desirable trait from a breeding point of view, as hornless animals have reduced defence possibilities against predators.[74]

Selective breeding occurred in the second half of the 20th century in the region of the former Soviet Union. Efforts are also being made in China to modify domestic yaks for breeding purposes.[75] The yak breeds distinguished so far are geographic breeds whose breed-typical traits are less manifested than in European land cattle breeds in the mid-19th century.[76] Geographical yak breeds are distinguished only for China. In the other countries it is not possible to speak of definable yak breeds. In Mongolia, for example, the cattle trade has a long tradition, so that characteristic differences could not develop due to the increased gene flow.[77]

Crossbreeds with bovine animals

Yak-cow hybrid

Mating is very rare between free-ranging cattle and yaks, as sexual behaviour differs somewhat. In contrast, when yaks and domestic cattle are managed in a herd, mating is more common because the animals are accustomed to each other. Yak cows, if there are yak bulls in the herd, will only allow themselves to be mounted by them. In order for yak cows to be shod by domestic cattle bulls, the yak bulls must be removed from the herd.[78] Male hybrids of the 1st and 2nd generation are infertile, while the female offspring remain fertile.[79] Cross-breeding of yaks and various local cattle breeds has a long tradition in yak-keeping areas, although there are individual regions where such bastardization is rejected for religious reasons.[80]

The performance of hybrids, usually referred to as Dzo in the western region, is usually above the average of the parent species. However, the heterosis effect of such crosses is difficult to measure because the husbandry conditions are usually not the same for the parent species and the crosses.[81] In China, progeny of domestic bovine bulls and yak cows are traditionally used for cart pulling and ploughing. They tolerate heat better than purebred yaks and can therefore be used in lower-lying areas. They are heavier and more fattening, their milk yield is much higher than yaks and they are also easier to steer than domestic yaks. However, this effect is already lost in the second hybrid generation.[82] There have been several attempts to create, by combination crosses, a hybrid breed combining the milk yield of domestic cattle with the yak’s resistance to adverse weather conditions and its ability as a beast of burden. However, these attempts have been largely unsuccessful to date and have been discontinued.[83][84]

Use of the house yak

Milk

Yaks give about 400 litres of milk a year. This is a small amount compared to domestic cattle or water buffalo. However, the fat content of the milk is high; it varies between 5 and 8.6 percent in the course of a lactation period. Raw cow’s milk, on the other hand, has a maximum fat content of five percent. Per kilogram, yak milk therefore has an energy content of about 3,650 kJ (871 kcal), while the comparable value for cow’s milk is about 2,680 kJ (640 kcal).[85] For the yak-owning population of Central Asia, it is accordingly of great importance in the diet.

The milking process is labor-intensive, as milk release in the yak is usually triggered only by the calf.[86][87] Therefore, two people are needed to milk a yak cow. The cow’s front or hind legs are first tied together with a rope to immobilize her. The calf is allowed to approach the udder for what is called priming, so that the milk shoots in. Once this happens, one person leads the calf away while the second person begins milking. During one milking, this procedure must be repeated three or four times. In total, not much more than one litre of milk is milked from the cow during this process, and because of the short teats, only strip milking is possible.[88] The lactation period of the yak is short due to the extreme climatic conditions and the often inadequate nutrition of the cows. In some areas of Nepal it lasts on average only from June to October.[89]

Dairy products

Tibetan monk making butter tea

Central Asian peoples have found several ways to preserve yak milk so that it is available for their diet year-round. Mongolian Öröm is made much like the clotted cream of the English counties of Devon and Cornwall, by heating the milk for an extended period of time while stirring it constantly. After resting for several hours, an inch-thick layer of fat has settled on the surface. Unlike clotted cream, Öröm is not only eaten fresh, but also dried.

Öröm is also the starting product of so-called yellow butter, which is similar to Indian ghee. For this purpose, oeema is often collected in special containers throughout the lactation period and undergoes a fermentation process during storage. To make yellow butter, this fermented oeema is heated with constant stirring and the fat and protein are separated using flour or similar clarifying agents. The yellow butter obtained is usually stored in leather bags and can be kept for several years. Among other things, it is drunk in traditional butter tea and is also used in religious ceremonies.[90]

In Nepal, a slightly different process is practiced to make yak butter. Here, the milk is boiled before churning and usually coagulated by a starter culture such as yoghurt. The next day, the solid mass is churned in a butter churn. The butter obtained is usually sewn into yak or goatskin and can also be preserved in this way for a long time.[91] The buttermilk is the starting product of Biaslag and Churbi or Sherkam, which are similar to cheese. Choormog is a slightly alcoholic drink made from a yogurt-like precursor.

Until a few decades ago, Central Asia did not produce soft and hard cheeses equivalent to those commonly produced in the Western world. As part of development aid projects, 9 cheese factories have been established in Nepal in recent decades, producing 990 tons of hard cheese and 30 tons of butter annually in the 1990s. The products are mainly sold to tourists in Kathmandu. The selling price was about four US dollars per kilo of cheese in the 1990s. The suppliers of the milk were paid about 0.2 dollars per litre of milk.[92]

Yak meat

Supply of yak meat in Yunnan

Yak meat is similar in appearance to beef. One kilogram of muscle meat has an average energy content of 1450 kcal, while comparable beef has an average energy content of 1850 kcal.[93] Yak meat is rich in iron and zinc. The meat is coarse-grained and has a low percentage of intracellular fat. It is deep red in colour due to its high myoglobin content.[94]

Yak fat contains an average of 19 mg of carotene per kilogram. This is significantly higher than beef fat, which contains only 7 mg. Yak fat is therefore significantly more yellow than beef fat.[95]

Meat is sometimes of great importance regionally. Fifty percent of the meat consumed in the highlands of Tibet and Qinghai, for example, comes from yak.[96] However, marketing opportunities are limited due to long distances and the slaughter of yaks is subject to religious restrictions. For religious reasons, Nepalese Sherpas do not kill their animals themselves, but commission members of other population groups to do so.

Slaughter is usually done to castrated bulls as well as cows at the end of their reproductive cycle. From the point of view of modern, Western-style agriculture, meat production is inefficient, as yaks are slaughtered only after they have suffered weight losses during the winter months, sometimes several times, and the ratio of meat produced to food consumed is unfavourable compared to domestic cattle.[97] This view, however, neglects the fact that yaks are kept at altitudes where other domestic species play little or no role. In the case of animals introduced in the Caucasus, this has been included in the evaluation of meat production. There it has been concluded that at altitudes between 3000 and 4000 metres the cost of a kilogram of live weight in domestic cattle is ten times higher than in yaks, and the annual cost of keeping yaks is only slightly higher than that of keeping sheep.[97]

Leather

Yak leather shoes

The hides of slaughtered yaks are somewhat smaller than those of cattle. Because of the yak’s hump-like back muscles, the hides are not usually processed as a whole. They are split before tanning.

Different peoples have developed different procedures to produce yak leather from the fresh hides. For most peoples, processing consists of only a few steps: the fresh hide is soaked for a long time in either buttermilk or water and then rolled. Some peoples wrap the hide in a tight roll and then repeatedly flex it with their feet over a period of three to four days.[98] In between the individual walking processes, the skin is rolled out again and again and stretched as well as dried.

Yak leather is durable, and Central Asian peoples use it to make saddles, saddlebags, straps, trap lines, belts, shoe soles, and various containers. Since mostly older animals are slaughtered, the leather is relatively thick and has long had the reputation of being of inferior quality to cowhide. In the meantime, the processing procedures in industrial leather processing have matured to such an extent that yak leather can also be processed satisfactorily. The centre of leather production is the Chinese region of Qinghai. In the 1980s, up to 650,000 yak skins were processed there annually.[99] In Tibet, the Lhasa Leather Factory is a leader in the processing of yak leather.

In Tibet, around 1950 and 1982, rowing boats with a frame of wooden poles covered with yak skins sewn together were used on calm waters, Heinrich Harrer reports with a color photo.[100]

Around 1968 a small round plastic boat, unsinkable by double shell, called “Sport Yak” appears in France and the USA.

Use of fur and faeces

After winter, the yaks’ fine undercoat is combed out and spun into yarn for clothing. The amount of undercoat obtained varies greatly and is as little as three kilograms in domestic yaks that have not been improved by breeding. In China, there is now a breeding line of Jiulong yaks in which individual animals produce up to 12 kilograms of fine undercoat.[101] The coarse wool and the cut belly hair are used to make blankets, ropes, bags and tents.

Yak dung is also used; at high altitudes it is sometimes the only fuel available.

Use as a workhorse

Loaded Yaks in Tibet (1939)

Yaks as pack animals, Tibet

Yaks were and are used as pack animals in most Himalayan trekking expeditions and mountain climbs, so their importance as beasts of burden is well known in the Western world. Although regions with yak husbandry are rarely at altitudes above 5500 meters. However, since yaks can survive at altitudes with a very low oxygen content, they are still used at altitudes of 7200 meters above sea level.[16] Yaks, which carry a weight of 60 to 80 kilograms, can cover between 20 and 30 kilometers a day.[102] They can carry much heavier weights, but then cover shorter distances. Maiwa yaks with a body weight of 480 kilograms have carried a pack weight of 390 kilograms for a short time.[103] Mainly castrated bulls (steers) are used.[104]

Yaks also serve as riding and draft animals. They are said to be a safer mount than horses in difficult terrain. They are able to swim across fast-flowing bodies of water, are sure-footed, and are much less likely than horses to show panicky reactions when crossing swampy terrain.[102] Some of the population groups that use yaks as mounts organize yak races at regular intervals.[14] Bulls are mainly used as draught animals.[102]

Literature

  • Ronald M. Nowak: Walker’s mammals of the world. 6. Edition. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9.
  • Jürgen Lensch, Peter Schley and Rong-Chang Zhang (eds.): The Yak (Bos grunniens) in Central Asia, Giessener Abhandlungen zur Agrar- und Wirtschaftsforschung des Europäischen Ostens, vol. 205, Berlin 1996, ISBN 3-428-08443-8
  • Cai Li and Gerald Wiener: The Yak, Bangkok, FAO Regional Office for Asia and the Pacific, 1995, ISBN 974-89351-0-8
  • Hans Hinrich Sambraus: Exotic cattle – water buffalo, bison, bison, dwarf zebu, yak, Eugen Ulmer KG, Stuttgart 2006, ISBN 978-3-8001-4835-6
  • Gerald Wiener, Han Jianlin, Long Ruijun (eds.): The Yak. FAO Regional Office for Asia and the Pacific, 2003; Second Edition 2006(online)

Film

  • Over the highest passes in the world. With a yak caravan through the Dolpo. (Alternative title: In den Bergen des Himalaya – Yak!) Documentary, Germany, 2009, 44:10 min., Written and directed by: Jan Kerckhoff, Production: Bayerischer Rundfunk, First broadcast: February 4, 2009 on BR, Summary by arte.

Web links

Wildyak

Commons: Bos mutus– Collection of images, videos and audio files

Hausyak

Commons: Bos grunniens– Album with pictures, videos and audio files

Commons: Yak breeding Pongratz– Album with pictures, videos and audio files

  • Yak breeding: Practical experiences (husbandry conditions, precautionary measures) on an Austrian alpine farm

Footnotes

  1. Peter Grubb: Order Artiodactyla. In: Don E. Wilson, DeeAnn M. Reeder (eds.): Mammal Species of the World. A Taxonomic and Geographic Reference. 3. Edition. Johns Hopkins University Press, Baltimore 2005, ISBN 0-8018-8221-4, pp. 637-722 (English, Bos grunniens [accessed December 4, 2020]).
  2. Jürgen Lensch, Peter Schley and Rong-Chang Zhang (eds.): Der Yak (Bos grunniens) in Zentralasien, Gießener Abhandlungen zur Agrar- und Wirtschaftsforschung des Europäischen Ostens, vol. 205, Berlin 1996, ISBN 3-428-08443-8, p. 17
  3. Cai Li and Gerald Wiener: The Yak, Bangkok, FAO Regional Office for Asia and the Pacific, 1995, ISBN 974-89351-0-8, p. 37
  4. Lensch et al., p. 42
  5. Lensch et al., p. 61
  6. Hans Hinrich Sambraus: Exotic cattle – water buffalo, bison, bison, dwarf zebu, yak, Eugen Ulmer KG, Stuttgart 2006, ISBN 978-3-8001-4835-6, p. 18
  7. Lensch et al., p. 67 and 69
  8. Li et al, p. 43
  9. Lensch et al., p. 217
  10. Lensch et al., p. 77
  11. Lensch et al., p. 78
  12. Lensch et al., p. 81
  13. Li et al., p. 54 and 55
  14. a b c d e Li et al, p. 55
  15. a b c d e Li et al, p. 56
  16. a b c d Li et al, p. 39
  17. Lensch et al., p. 59
  18. Lensch et al., p. 50
  19. Li et al., p. 46
  20. Lensch et al., p. 59
  21. Li et al, pp. 146-148
  22. Lensch et al., p. 21
  23. Lensch et al., p. 24
  24. Yak on the IUCN Red List, accessed 10 September 2011
  25. Lensch et al., p. 62
  26. a b c Lensch et al., p. 64
  27. Lensch et al., p. 146
  28. Lensch et al., p. 146 and 147
  29. Lensch et al., p. 119
  30. Lensch et al., p. 151
  31. Li et al, p. 75
  32. Lensch et al., p. 67
  33. Lensch et al., p. 86 and 88
  34. Li et al, p. 74
  35. a b Li et al, p. 57
  36. Li et al, p. 73
  37. Lensch et al., p. 84
  38. Li et al, p. 58
  39. Lensch et al., p. 91
  40. Li et al, p. 69
  41. Lensch et al., p. 92
  42. Lensch et al., p. 20 and 21
  43. Li et al., pp. 2 and 3
  44. Lensch et al., p. 25
  45. Li et al, p. 3
  46. Lensch et al., p. 26
  47. Thus in the Guoyu Chuyu of the Western Zhou period and the Shanhaijing Zhogshanjing (c. 400 BC). Cf. Wiener, Han & Long (eds.; 2006), p. 4
  48. Li et al, p. 4
  49. Li et al, p. 5
  50. a b Li et al, p. 130
  51. Li et al, p. 133
  52. Li et al, p. 136
  53. Li et al, p. 137
  54. Lensch et al., p. 27
  55. Li et al, p. 70
  56. Li et al, p. 2
  57. Li et al, p. 173
  58. Li et al, p. 183
  59. Li et al, p. 171
  60. Li et al, p. 170
  61. Li et al, p. 166
  62. Li et al., p. 192
  63. Lensch et al., p. 31-37
  64. Li et al, p. 42
  65. Li et al, p. 6
  66. Li et al., p. 31
  67. Lensch et al., p. 38 and 39
  68. Lensch et al., p. 39
  69. Lensch et al., p. 40
  70. Sabine Holzknecht: About life with the mountain. In: Alpin. July 2004, ISSN 0177-3542, p. 22(online[PDF; 1.1 MB; retrieved 4 December 2020]).
  71. Lensch et al., p. 86 and 94
  72. Li et al, p. 140
  73. Li et al, p. 137 and 138
  74. Lensch et al., p. 95
  75. Li et al, p. 24
  76. Lensch et al., p. 97
  77. Lensch et al., p. 103
  78. Li et al, p. 76
  79. Lensch et al., p. 106
  80. Lensch et al., p. 111
  81. Li et al, p. 108
  82. Lensch et al., p. 115
  83. Lensch et al., p. 117
  84. Li et al., p. 34 and 35
  85. Lensch et al., p. 179
  86. Lensch et al., p. 69
  87. Li et al, p. 137
  88. Sambraus, p. 19 and 20
  89. Lensch et al., p. 168
  90. Lensch et al, pp. 184-185
  91. Lensch et al, pp. 183-185
  92. Lensch et al., p. 187
  93. Lensch et al., p. 201
  94. Li et al, p. 99
  95. Lensch et al., p. 203
  96. Lensch et al., p. 206
  97. a b Li et al, p. 97
  98. Lensch et al., p. 213
  99. Lensch et al., p. 209
  100. Heinrich Harrer: Wiedersehn mit Tibet. Innsbruck 1983. edition Buchgemeinschaft Donauland, 1983. colour photo, p. 182. –
    A triangular frame of 4-7 cm thick wooden poles, two each 3 and one 2 m long, form the board edge of the prismatic frame, to which the skins are stretched upwards. The bottom is flat, the sides are curved outwards in places by vertical arches. The oarsman stands in the point. The boat holds an estimated 5 passengers.
  101. Li et al, p. 101
  102. a b c Li et al, p. 105
  103. Li et al, p. 106
  104. Li et al, p. 142
This article was added to the list of articles worth reading on October 2, 2011 in this version.