Part 3 Yak in nontraditional environments by Gerald Wiener^[13]

Overview

Information is presented here on yak kept commercially in around 90 herds in the USA and Canada with a total of perhaps 2000 animals (pure and hybrid). Yak are also found in small commercial herds in parts of Europe and in New Zealand. In addition, there are a significant number of zoos and wild animal parks in several parts of the world that have, or have had, collections of yak, many of them successfully self-reproducing herds. The common factor for all of these yak is that they are in climatic and management situations which are quite atypical of those in the traditional yak-keeping territories. The successful survival and reproduction of the yak in these nontraditional environments is, therefore, of wider interest for the potential adaptation of yak to a variety of conditions worldwide.

North America

Since the early 1980s there has been a growing interest in yak by commercial breeders and ranchers in the USA and Canada hoping to exploit what they claim to be the low maintenance needs of yak and the potential for lean meat production through what is referred to as "crossbreeding" with other cattle - but should, more accurately be termed "hybridizing". At the time of writing there are an estimated 90 breeders, but perhaps fewer, with a total of not more than 2 000 yak and hybrids between them. These numbers are lower than reported earlier (Wiener, 2002) as breeders have recently found difficulty in penetrating the meat market, except on a local basis (J. Delaney, personal communication, 2002). Individual herds vary in size from less than ten animals to more than 400. The great majority of yak breeders in North America are members of a breed Association, the (American) International Yak Association (IYAK), but some of those still registered with the Association no longer have yak.

From a biological point of view, perhaps the most interesting aspect of this commercial use of domestic yak in North America is that many of the herds are located in parts of the country where the climate and general environmental conditions are very different from those traditional for yak. Around half of all the herds, including the largest, are in areas close to the Rocky mountain range at elevations up to around 2 600 m above sea level, where yak might be expected to feel perfectly "at home". Some of the remainder are in hill areas in other parts of the country, but a significant proportion of the herds are in seasonally hot parts of the country at low altitudes and in typically temperate climates - some close to the Pacific coast. The single largest herd is in Nebraska, east of the Rocky mountain range at 1 280 m above sea level and with an annual rainfall averaging 420 mm.

Overall, the herds are located from northerly parts of Alberta in Canada to central USA and from the Pacific coast to close to the Atlantic. This clearly shows an ability of the yak to adapt to non-traditional conditions - in spite of the contrary view expressed in some of the early literature on the subject, which is also part of the "received wisdom".

A historical note on the introduction of yak to Canada and Alaska

The introduction of yak to Canada and Alaska in the early part of the last century represents the most northerly latitudes in the distribution of the yak (other than the progenitors of the modern yak). The origin of the yak in this region is not clearly documented. It is known that six head of Chinese yak were sent to Canada in 1909 (from England, according to Lensch et al., 1996), as a gift from the Duke of Bedford, but by the following year only one male and three females had survived and for the next two years the animals failed to reproduce. This, as noted by White et al. (1946), was attributed to the low altitude at which the yak were kept. Reproduction started when the animals were moved to higher altitudes (and probably, therefore, lower temperatures) in the Rocky Mountain Park near Banff in Alberta, Canada. In 1919 most of the yak were transferred to Buffalo Park, Wainwright. In 1921, some yak were included in the hybridization experiments with domestic cattle and American bison then in progress at Wainwright with the aim of producing an animal for meat production for the harsh pastoral conditions of northern Canada. Few of the interspecies hybrids survived (Deakin et al. 1935) and this series of trials was suspended in 1928.

Similar experience occurred in Alaska (White et al. 1946). Over the years 1919, 1923 and 1930, a total of three male and six female Chinese yak, born in Canada, were taken to the Fairbanks Experiment Station in Alaska, at an elevation of approximately 130 m. The yak had great difficulty in breeding, but these difficulties diminished and the general condition of the yak improved when they were moved to a plateau at an altitude between 400 m and 800 m. The intention was to produce animals suitable for the grasslands in the Alaska mountains, southern Yukon territories and plains and tundra of the Alaska-Canada border. Hybrids were produced experimentally with Galloway cows whose hybrid offspring were heavier at slaughter than either the yak or the pure Galloway. However, the hybrids did not appear to withstand the extremely low temperatures of winter as successfully as the pure yak. These trials were also suspended, in the early 1930s.

In theory, it is feasible that the entire North American yak population could be derived from the single, documented, importation to Canada, but this seems improbable. Offspring from the original importation of yak survived in national parks or zoos, but these institutions may also have imported additional yak from abroad through dealers. There are unconfirmed reports that some of the present-day yak there are derived from an importation to the Bronx Zoo in 1890. Also, as the section on yak in zoos later in this Chapter shows, some significant breeding of yak, and also a few yak hybrids with cattle, occurred in North American zoos from the 1920s onward.

Surplus animals and dispersal of zoo collections could well have provided progenitors for the present commercial population - though documented evidence of that has not been found.

Characteristics and performance

Most of the information that follows was provided by members of the (American) International Yak Association (IYAK). Animal performance results are based on figures from about 16 herd owners.

The primary aim of the yak breeders in North America is lean meat production, but fibre is also valued especially in some smaller herds. Only one of the respondents to our survey trained yak for packing and trekking but not on a commercial basis. A very small number of yak are also kept out of curiosity or as pets. During the period of expansion of this niche market, much of the interest and income of breeders came from the sale of breeding stock, but this may be changing. Milk from the yak, though referred to in the promotional literature of IYAK, does not appear, as yet, to have found a market, although one or two breeders report some trial milking for the manufacture of yoghurt.

Coat colours of the yak are: all black, black with some white markings (called trim), which predominates, black and white (described as "royal") and a "gold" colour, present in small numbers and said to be recessive to black.

Birth weights of yak calves are quoted as varying from 13 - 27 kg, weaning weights, generally at four to five months of age, as 65 - 70 kg for some farms thought to be providing above-average rearing conditions. Adult weights of yak cows were quoted in the range 240 - 360 kg and yak bulls 550 - 680 kg, though one yak bull in Canada was reported to weigh 820 kg.

Some females are mated for the first time as early as 18 months of age, but two to two and a half years is more common. Calving annually is normal, but one of the herd owners noted that half his yak cows had only two calves in three years. Bulls are not generally used for mating until three years old, although some younger ages were reported.

Few health problems were encountered but the need for routine vaccinations and deworming, especially in humid conditions, was referred to by several of the herd owners.

Feeding and management

Most of the feed is natural grazing in summer and hay in winter. Some breeders use grain as an enticement to gather the animals, but a few feed it as a supplement - especially for finishing. All the respondents to the survey provided mineral blocks and some mentioned a need for an adequate amount of copper in the block to promote health and the breeding of the yaks (as noted in Chapter 9). A greater feed efficiency was claimed for the yak and their hybrids relative to other cattle and hence a need for relatively smaller quantities of feed and pasture per kilogram live weight of animal.

Generally, the yak were kept out-of-doors all year-round. Calves remain with the dams up to weaning at, usually, four to five months old. The yak were regarded as reasonably tame and, with few exceptions, easily handled and easily confined by fencing.

Possible heat stress for yak was mentioned but did not amount to a problem. The animals sought some shade and water for cooling in periods of high heat in summer, but even this was thought to be unnecessary by some of the respondents.

Discussion

The performance information suggests that the range of birth weights of yak calves may be a little higher than those in traditional yak areas in China. Also, the inferred growth rate of calves to weaning, perhaps exceeding 400 g per day, is also higher than the gains of around 300 g quoted elsewhere in this book. However, this should not occasion surprise as the calves in North America are reared under what can be regarded as good conditions and with access to all the maternal milk, while in the traditional yak territories herders normally take some milk for domestic consumption - thus restricting the intake by the calf. Experimental results from China, quoted in Chapter 6, show similar improvements in calf growth when the calves are given access to all their dams' milk. Some of the adult weights, particularly of breeding bulls, also appear slightly higher than usually reported for domestic yak, but this is likely to be a consequence of feeding rather than a genetic difference.

The owners of the herds surveyed reported what are higher reproductive rates for their yak than are common in the more traditional circumstances. This includes both an earlier average onset of breeding and, mostly, annual calving. This is almost certainly attributable to the feeding conditions in summer and the almost universal use of supplementary feeding in winter, as well as the provision of mineral blocks and health care. Consequently there is no large loss of weight or condition of the animals over winter and during pregnancy.

Questions remain regarding the origin of the North American yak population and hence its genetic relationship to other yak populations and breeds. It is also not known how closely related the animals are within the North American yak population and whether inbreeding is or might be a problem as the genetic base of the population might well be small. Future research may resolve some of these questions.

It seems almost inevitable that over time there has been some introduction of B. taurus genes into the American yak gene pool. Preliminary results, from a recent analysis of some 43 blood samples from yak of three of the herds in the USA (Han Jianlin, personal communication, 2002), suggest the presence of mitochondrial DNA from cattle in many of these particular samples. However, it is unlikely that such introductions of B. taurus blood would be responsible for the apparent adaptation of the yak in North America to the varied and non-traditional environments. For yak, any such introduction of genes can come only through hybrid females, as the hybrid males are sterile. The process of hybridizing seems to be random and varied and without selective intent for "adaptation". Moreover, it would also be unlikely that natural selection for adaptation could have been effective over the short period of 90 years or so under consideration. These points were given more detailed consideration by Wiener (2002).

More information about the distribution and performance of the yak in North America were provided by Wiener (2002) and can also be obtained from the IYAK Web site (www.yakpage.com).

Europe

A small herd of 26 yak was established, in the 1990s, in the Zermatt region of Switzerland at an altitude of 1 600 m. The animals were acquired over a period of two or three years from a dealer, but the origin of these yak is not recorded (Agir, 1997). More recently, Michael Goe (personal communication, 2002) reported that this herd had grown to 37 yak (and one hybrid cow) with the herd in Emd (Canton Valis); in addition, he reports two other herds of 20 animals and one of 15 yak and a further number of very small herds (two to seven animals). The total number of yak for Switzerland was estimated to be 140. The yak in the herd first reported were used for trekking.

The only other herd, according to Horst Geilhausen (personal communication, 2002) that is extant in Europe, outside zoos, numbers eight to ten animals in the south Tirol of Austria. It was established in 1985. The owner is said to accompany his animals personally to the mountain pastures in the spring of the year and from this one might infer that the yak are kept in more sheltered parts over winter. (The origins were not conveyed to Professor Geilhausen). The presence of yak in parts of France, as in the last century and earlier (see Chapter 1) is no longer reported.

New Zealand

A small herd of about 15 yak is kept at the very top end of South Island of New Zealand on a farm just above sea level with an annual rainfall of 2 400 mm and a mild climate - with summer temperature often in excess of 30^oC.

The yak originated in the mid-1980s from the Toronto Zoo and first went to a holding in central South Island at an elevation of about 300 m, with cold dry winter but hot summer, where the yak bred well. They were transferred to their present farm in 1990 and, according to the owner (information from the year 2000), after a period of acclimatization, the yak started to reproduce well, calving annually in November (late spring-early summer). Some of the yak have been sold to other farms in the area as a foundation for new herds. The owner reports that his yak have had no health problems and, like the ranchers with yak in North America, notes that his yak appear to eat much less than his other cattle and thrive on roughage.

Yak in zoos and wild animal parks

The basic information in the first part of this section was kindly provided by the Wildlife Conservation Society in New York in the form of a Taxon report, which lists animals, past and present, by location Other information is acknowledged in the text.

Yak have been present in zoos and wild animal parks in Europe, North America and Asia for well over a century. Some of the collections, past and present, are very small and transient, relying on purchases from elsewhere. Other zoos have more substantial and self-reproducing herds, which in turn have surplus stock available for disposal. The critical point of interest, from the point of view of yak adaptability, is that these zoos represent conditions that are quite different from those experienced by yak in their native habitats. Success or failure in captivity provides some further clues therefore to the adaptability of yak to a variety of different environments.

Most of the zoos take part in a registration system for their animals - with the information published in a Taxon report. The information here is based on such a report and it provides evidence of 110 zoos and wild animal parks with yak either past or present (up to the year 2000). Not all zoological institutions, however, participate in this information scheme, so this number is a minimum estimate.

Three of the collections have had, over a period of years, well in excess of 100 yak each (Winnepeg, Canada; Whipsnade, England, with the largest number currently extant, and Bronx, New York, USA - collection now dispersed). One of the zoo collections (Milwaukee, Wisconsin, USA) dates back to 1914 (but with a last entry in 1949). One other, (San Diego) dates back to 1928 (but the last entry is in 1980), and the remainder are from 1940 onwards, with the majority starting after 1980. Many of the collections started were dispersed within ten years or so. (In terms of dates, one animal was found in these records born at the National Zoological Park in Washington as early as July 1901, many years ahead of other yak at this zoo, and then traded to Regent's Park Zoo in London the following January). For zoos or parks that had yak in the year 2000, the average number of years that they had had their yak herds was around 20. Zoos now without yak had kept their herds or animals for only half that time. A few of the zoos have exhibited only the odd yak or two and have not bred them. Table 11.2.20 summarizes the information on a country basis showing 102 locations. Because of the dispersal of many of the collections and disposal of animals, the number of yak extant (in the year 2000) is only a fraction of the total number recorded over the years.

Nearly all the yak represented in the survey were born in captivity or can be presumed to have been. But there is no information readily available on the origin of some of the early acquisitions and no information of the source of animals acquired from dealers. There is no absolute certainty that all the captive yak are pure or whether they are hybrids with infusions of blood from other cattle. However, the zoos represented in this report keep accession and breeding records, and the great majority of the animals are listed as pure domestic yak and only a small minority is labelled as hybrids or as possible hybrids.

Only three zoos claimed some wild yak in their collections; the largest of these, Chicago zoo, in the period 1974 - 1981, with 17 animals. Unlike the domestic yak in the zoo collections, none of the wild yak survived for more than three years.

It is clear from the summary in Table 11.3.1 that captive yak have existed and are still found in a wide variety of climates and environments and from the available evidence those in small herds have bred and survived successfully in captivity. The environments, captivity apart, are for the most part atypical of the conditions in the native habitats of the yak. Most of the locations of the zoos and wild animal parks are at relatively low altitudes, some close to sea level, and thus do not present the "typical" atmosphere low in oxygen. Also, summer temperatures at many of the locations will be high, even relatively so at night. Winters will be temperate in many cases, and average annual temperatures will be at higher average levels than for yak in their native territory. (This is similar to the conditions referred to earlier in relation to a proportion of the yak kept commercially in North America.)

Some reconciliation is therefore needed between the obvious tolerance of the yak of these "unusual" conditions and the reputation of yak for poor adaptation to low altitudes and high ambient temperature (based on yak-keeping experience in their principal territories and a little evidence from small-scale studies).

Table 11.3.1 Yak collections - past and present - in zoos and wild animal parks*

* Not all zoos participate in the information scheme represented by the Taxon reports or appear in ISIS abstracts - these zoos (and some countries) are therefore missing from the Table.

** One of these zoos is in a CIS country. At least two zoos (Moscow and St Petersburg) in the Russian Federation, but not listed in the Taxon report, are known to have had, or currently to have, yak collections.

The apparent success of commercially kept yak in parts of North America (see earlier section) further underlines this point. Winter et al. (1989) also refer to this conundrum. Perhaps it is all a question of the time allowed for such acclimatization and how the animals are managed on arrival.

It can be surmised, for example, that in past times on the trade routes from Tibet southward into Nepal and India, yak would fairly rapidly descend from cold mountain regions into near-tropical conditions and that this may have produced not only heat stress in the animals but a reputation for intolerance of heat, which has become part of the received wisdom. This is conjecture, of course, and the opportunity to record the physiological responses of yak on such treks to a descent from cold to near-tropical conditions no longer presents itself readily. (Although nowadays, study of such responses would undoubtedly be considered as worthy of an academic project!)

Whipsnade Wild Animal Park

In the first edition of this book, the yak herd at Whipsnade was featured as demonstrating the point previously made, that yak can survive and reproduce well under conditions that are atypical of those in the native habitats of the yak. It is of interest in this context to provide updated information on this small but successful herd, by courtesy of the curator of Whipsnade, Nick Lindsay, and the chief veterinarian, Edmund Flach.

The park lies on the edge of the Dunstable Downs (elevation approximately 150 m, approximately 52^oN) in England. The climate is typically temperate. The herd was started in 1944, though records of the source are not now available. This was followed by small importations from Alberta (Canada), Berlin (Germany) and from Sweden, among others. Currently, the herd numbers about 30 animals with a second small herd established at another park with animals originating from the Whipsnade herd.

The information provided is that the yak cows do not calve annually, but each has, on average, approximately two calves in every three years. The animals grow normally and survive extremely well. Small numbers of yak have been sent to other countries (e.g. Turkey). There is no obvious seasonality to the breeding and calves (all pure yak) have been born in March, April, May, July, August, September and November. It appears that some of the yak at Whipsnade may breed as early as their second year of life. Since the foundation of the yak herd in 1944, there have been more than 100 yak in the Whipsnade herd (with the offshoot herd in addition) and the vast majority of them have been born at the park.

In summer, the animals are said to seek shade under trees and shed much of their fleece but show no obvious discomfort. The only recurrent health problems were found to be associated with copper deficiency. Following diagnosis of the condition, it has been fully controlled by regular supplementation and occasional copper injection for many years (Edmund Flach, personal communication, 1995). This matter was referred to more fully in Chapter 9 as there is a possibility that yak may be prone to this deficiency for genetic reasons because other cattle in the park are not equally affected, although receiving the same diet. Other data from the herd are presented in Chapter 4.

A note from the curator states that as of 2002, breeding of this long-standing herd was being suspended temporarily, as there has been insufficient demand for surplus animals. But the matter is under review.

References

Agir, (1997). Elevages exotiques en Suisse. Actualités, 30 Août 1997

Deakin, A., Muir, G.W. and Smith, A.G. (1935). Hybridization of domestic cattle, bison and yak. Publication 479, Technical Bulletin 2, November 1935, Dominion of Canada, Department of Agriculture.

Lensch, J., Sley, P. and Zhang, Rongchang (1996). Der Yak (Bos grunniens) in Zentralasien. Duncker & Humblot, Berlin. (IBSN 3-428-08443-8)

White, W.T., Phillips, R.W. and Elting, E.C. (1946). Yak and yak-cattle hybrids in Alaska. J. of Heredity, 37, 355-358.

Wiener, G. (2002). Adaptation of yak to non-typical environments: A preliminary survey of yak in North America. Proceedings of the third international congress on yak, in Lhasa, China, 4-9 September 2000. International Livestock Research Institute (ILRI), Nairobi, pp. 373-379.