Breed History of Heritage Yak in North American.
INTRODUCTION TO NORTH AMERICAN YAK (Submitted to Livestock Conservancy, Sept. 2020)
The North American Yak. The North American Yak is one of the few historic breeds of livestock originating in Canada. It descends from Tibetan yak which were brought to Canada between 1907 and 1927. This population was shaped by human intervention and natural selection in the rugged environment of western Canada and the northern United States, and the resulting breed became known as the North American Yak. The breed is closely associated with Montana, but today the majority of the North American Yak are found in Colorado.
Recognized as valuable for its superior environmental adaptation, the Canadian and American governments encouraged and financed the importation of breeding stock into Canada and Alaska. In 1909, large scale promotion of North American Yak as New World livestock began America. The North American Yak flourished and by 1916, there were several successful breeding herds in eastern Canada, Fairbanks Alaska, Massachusetts and New York.
Yak genetics were introduced as a way to increase meat production, though the result was to dilute the characteristics of the Yak without any market advantage gain for the breed. Fortunately, several cross-species hybridization efforts failed due to the sterility of F1 offspring. In 1937, the Canadian government officially discontinued the hybridization efforts with the North American Yak in favor of “improved breeds.” These federal herds were divested and moved to private sector breeders. While these types of Federal experimental farms continued into the 1950s in Alberta, due to diligent breeders and well documented pedigrees the pure stock continues to exist. The breed continued to flourish for several decades. In the early 1980s, additional Canadian seed stock was added to preexisting herds in Montana, Colorado, and Nebraska. Several new herds were established and the North American Yak territory was expanded throughout the northern United States.
The North American Yak breed is endangered and most of the remaining pedigreed animals are still found in and around Montana as of 2020. Small herds do still exist in Canada and across the US. The breed has had established breeding populations since 1920, and over the last 100 years the herd has grown to an estimated 10,000 animals powering a thriving meat industry. The foundation stock is no longer available and the breed is globally endangered.
The breed merits attention for use in grass based ranching, especially where stocking levels are restricted and environmental conditions are harsh. Under these conditions, the North American Yak will be able to demonstrate its value to meat ranchers, fiber producers and dairy farmers and thus gain a broader base of support.
NorthAmerican Yak are black, brown, or piebald. Many have a mane which in native black types is gray and In a Native Black the gray coloration is expressed as a dorsal stripe…
longer hair running down the back. This is called a dorsal stripe, seen in the Native black type and the hair is grey. The spinal hair of Imperials is not usually considered a true dorsal stripe. The horns often curve up and turn back forming a primigenius spiral with age. Highly sexually dimorphic, cows weigh about 600 pounds, and bulls about 1,600 pounds. The milk ¬is called Natural Concentrated milk because of its high fat (5.5–7.5%) and protein (4.0–5.9%) content. Milk production is about 1,100 pounds per lactation. This allows cheesemakers to make significantly more cheese from less milk. Most significant is the breed’s ability to produce milk and lean red meat on poor forage and under very challenging conditions. Few livestock breeds demonstrate this combination of hardiness and ¬productivity as well as the North American Yak.
The North American Yak is a True Genetic Breed. The North American Yak is a True Genetic Breed as defined by the Livestock Conservancy. When mated together, the North American Yak reproduces a well-defined breed type that differs phenotypically and genetically in significant ways from other international yak breeds. The NAY most closely resembles an indigenous Tibetan Bos mutus subtype that is reportedly now extinct, and according to researchers (Weiner, 2014), nomads called this wild-type yak the “Long-hair forehead fur yak” (Chi. 长发 额头皮毛牛, Tib. རིང་པོ སྐྲ སྤུ དཔྲལ་བ། འབྲོང). While Weiner believed this was most likely a distinct wild-type population in the Yushu region of Tibet, in North American Yak this breed is often referred to as the “Wooly” or the “Super Wooly”.
The “Wooly” North American Yak is characterized by long dense black or dark-brown fiber, a black nose, large round head, high hump, and large horn base, often developing a primigenius spiral with age (formal Judging Criterion was first developed in 1986, available on request). The North American Yak is a Bos mutus subspecies, native to North America for over 100 years, and it is facing extinction. This is an irreplaceable piece of earth’s biodiversity and offers variety that may be needed for future farms both in the US and abroad.
The yak is a large wild bovid native to the Himalayas. Bos mutus is genetically distinct from, and the ancestor to, the Bos grunniens subspecies of yak. While Bos grunniens are prolific and have a global population of an estimated 15 million, the subspecies are endangered (Bos mutus). While interaction with humans have domesticated North American Yak, they are most similar to Bos mutus both phenotypically (Weiner, 2014, Porter, 2019) and in preliminary genetics comparisons (Porter, 2018). North American Yak (Bos mutus grunniens) are less introgressed than the Bos grunniens grunniens yak subspecies on the Qinghai Tibetan Plateau, and they retain several genetic and physiological markers that more closely resemble Bos mutus (Qui, Q. et al, 2013; Qui, Q. et al, 2015). This preliminary data is currently being replicated in a direct genetic comparison by the Yak Genotyping Team at University of Wisconsin-Madison, led by Dr. Hasan Katib, with Nicole Porter and Camila Urbano Braz. This is the largest study of yak undertaken to date and will compare North American Yak to both Bos mutus and various Bos grunniens breeds in Tibet to examine these genetics trends.
North American Yak Domestication. North American Yak are a docile Domesticate that is phenotypically and genetically most similar to Bos mutus in preliminary research, but is likely a cross breed (subsp. mutus x grunniens).
Agricultural Uses. The original importation of yak to North America was motivated by the effort to introduce a meat stock that had the advantages of being a heartier and cold tolerant breed. The American market has responded with enthusiasm to yak. North American Yak meat has grown in demand over the years and continues claim top dollar prices. Per pound yak meat prices are currently higher than grass-fed, organic beef. Breeders regularly struggle to meet demand and sell out their yak products before they become available. Currently, many new community members are entering yak ranching, attracted by these monetary advantages (e.g. high stocking capability, low forage quality requirements, and high meat value). There is also a greatly underutilized potential in North American Yak, in which ranchers could benefit from the luxury fiber and health-driven, exotic dairy market as well. There is much research supporting the ability of yak to decrease Climate Change (e.g. lower methane emissions, lower stocking rates, prairie bison replacement, etc.), as well as offering a heart healthy dairy and lean red-meat alternative (e.g. lower fat, higher Omega 3s, more good cholesterol, optimized for the Keto diet, etc.). With education, North American Yak will demonstrate its value to consumers and meat ranchers, as well as fiber producers and dairy farmers and thus gain a broader base of support.
Current Heritage Products. Yak products have been recognized as coming from a Heritage Breed by various other national and international associations. Prairie Sky’s, Tibetan Yak Gruyère from Ragya Monastery in Tibet, is currently listed with Slow Food International and Slow Food USA as a World Heritage Food and was acknowledged as such at the World Food Expo in Terra Madre, Italy and the World Championship Cheese Contest in Madison, Wisconsin in 2020.
Endangered Breed. The North American Yak are Endangered, as defined by The Livestock Conservancy, and meet criterion for the Critical category.
Critical Category. Annually, there are fewer than 200 registrations of The North American Yak in the United States, and there are fewer than 2,000 (n≈ 1256) of The North American Yak breed world-wide.
Globally Threatened. Not only was the North American Yak developed since 1919, the breed is globally endangered. The North American Yak (Bos mutus grunniens) does not exist outside of North America. The indigenous Tibetan Bos mutus subtype (Eng. Long-hair forehead fur yak, Chi. 长发 额头皮毛牛, Tib. རིང་པོ སྐྲ སྤུ དཔྲལ་བ། འབྲོང) is now reportedly extinct. It’s closest genetic relative, Bos mutus, is extinct in Bhutan, and its presence in Nepal is unconfirmed. It is currently considered to be Vulnerable by the International Union for Conservation of Nature (IUCN). The yak is under first-class protection in China and is included in Schedule II, Part I of the Indian Wild Life (Protection) Act of 1972. The yak’s population has declined at least 20% over the last 20 years. It was previously classified as Endangered, but was downlisted to Vulnerable in 1996 based on the estimated rate of population decline and current population sizes. The latest global assessment in 2014 suggested a total population of no more than 7,500-9,999 mature individual Bos mutus yak in the world (Buzzard, et al., 2014). More recent estimates indicate that these numbers are continuing to decline (Burger, 2014) or remain stable, with the Bos mutus yak remaining Vulnerable (Schaller, et al, 1996, 2007; Buzzard, 2015).
A Long History in North America. North American Yak have been in the US for over a century. The first mating pairs of Bos mutus in the US were moved to the Bronx Zoo prior to 1871. By 1901, yak were reproducing at a variety of American exhibits (New York Department of Parks, National Zoological Park, Washington, DC, and Milwaukee County Zoo, in Wisconsin). For additional information see Tables 1-5.
At the turn of the century, several breeding herds of yak were imported to North America and were established with the goal of breeding a more cold-hearty livestock. The first importation of yak to Canada occurred in 1909 for agricultural trials. The Duke of Bedford sent a Bos mutus breeding herd from his estate, Woburn Abbey, England to Brandon, Manitoba. In 1910, a second herd was established in Rocky Mountain Park, Banff, Alberta, and a third was Buffalo Park, Wainwright, Alberta. In 1927, “A Brief History of the Yak in Canada,” was published by Archibald, E. S. Annual Reports, Division of Animal Husbandry, in Ottawa. For additional information see Tables 1-5.
This first promotion of North American Yak as New World livestock to the American public began in 1909. The first large scale breeding population in the United States began in 1919 and was being carried out by the United States Department of Agriculture in Alaska at the Fairbanks Experimental Station. Yak were recognized as valuable for their superior environmental adaptation and the goal of the project was to cross-breed these qualities into common cattle. The North American Yak flourished and by 1920, there were several successful breeding herds in eastern Canada, Fairbanks Alaska, Massachusetts, and New York.
Yak genetics were introduced as a way to increase meat production, though the result was to dilute the characteristics of the Yak without any market advantage gain for the breed. Fortunately, several cross-species hybridization efforts failed due to the sterility of F1 offspring. In 1937, the Canadian government officially discontinued the hybridization efforts with the North American Yak in favor of “improved breeds.” These federal herds were divested and moved to private sector breeders. While these types of Federal experimental farms continued into the 1950s in Alberta, due to diligent breeders and well documented pedigrees the pure stock continues to exist.
The breed flourished for several decades. Multiple herds were established and the yak territory was expanded throughout northern United States. Beginning in the 1980’s North American Yak experienced a boom. Several Canadian and American breeders became interested in yak and aggressive trading occurred across the International Boundary of the Canada-United States border. The original Canadian seed stock and Alaskan stock continued to support the growth of preexisting Montana and Nebraska herds.
The North American Yak breed has had established breeding populations since 1920, and over the last 100 years the herd has grown to an estimated 10,000 (primarily unpedigreed and unregistered) animals powering a thriving meat industry. However, only a handful of these yak are bred following established “Best Practices” created by the founders of the first and premiere breed association, International Yak Association (IYAK). IYAK was established by Lawrence Richards in 1992. Between 1992 and 1993 Dr. Dane Smith and Lawrence Richards wrote the Registration Rules for the North American Yak Registry (NAYR) and began registering yaks and promoting Single Sire breeding. Under the presidencies of Mike Swartz and Jim Watson, IYAK initiated mandatory UC Davis based DNA testing, first for Sires and later for Dams. Then under the presidencies of Gregor Dike and Jandy Sprouse, in 2015, testing was upgraded to Neogen’s GeneSeek using Single Nucleotide Polymorphisms (SNiP’s). In 2018, with the help of Genome Committee Chair, Nicole Porter PhD, algorithms for the analysis of raw data for parentage, COI, introgression and a variety of traits and diseases, were developed, automated, and required by IYAK for registration from 2018-2020. Under the current administration, this SNP genetic testing is no longer required to register with IYAK, opening the doors of the registry to cattle-yak hybrids, highly inbred animals, and those with no known parentage or verified pedigree.
Currently, IYAK is only weakly upholding their own Mission Statement, or their professed commitment to preserve yak pedigree. In addition to IYAKs declining standards, they successfully registered only a handful of animals in 2019 and 2020. The USyak Association allows hybrids into their registry and actively supports breeding practices with the goal of hybridization. For these reasons, responsible breeders with an interest in preserving genetic integrity have nowhere to register their animals. We are currently proposing a third “umbrella” association (working title: World Heritage Yak Conservancy) to fill this gap (see Purebred Status and Breed Associations below).
Foundation Stock is No Longer Available. Not only was the North American Yak developed since 1920 and the breed is globally endangered, the foundation stock is no longer available. In 1989, USDA's Animal and Plant Health Inspection Service (APHIS) put a moratorium on importation of yak and yak semen into the US from countries that have instances of Prion disease, due to the deleterious effects of Bovine Spongiform Encephalopathy (BSE). Even were the moratorium lifted, Bos mutus are a protected species and they would not be available for export. At this point, attempts at Artificial Insemination (AI) in the US have been highly unreliable. Therefore, AI is unsustainable as a yak breeding practice, even were Bos mutus semen to somehow became available for import. Moreover, the original yak European seed stock is also now largely extinct and the few remaining animals in Germany and Switzerland are also subject to importation restrictions. Today, the North American Yak remnant population is sequestered and needs to sustain itself in situ to be preserved.
PUREBRED CRITERION
Purebred Status. To meet the World Heritage Yak Conservancy (WHYC) criterion for registration in the NAHYR, yak must be from a pedigreed lineage verified by genetic testing. These animals will be considered a part of the Foundation herd of North American Yak. This criterion will be verified by Neogen’s GeneSeek (Summary below, complete criterion by Lawrence Richards available on request).
Purebred Importation Cut-off. The last verified importations of yak to NA yak breeding stock that are currently being bred, occurred between 1943 and the 1960’s. When the exact date is confirmed this will be the cut off for inclusion as a Heritage Breed at World Heritage Yak Conservancy (WHYC) in the North American Heritage Yak Registry (NAHYR). Future importations of Bos grunniens would not qualify for Purebred registration by WHYC in the NAHYR. In the event of a future bottleneck, WHYC would petition the Livestock Conservancy for permission for a one time import of DaTong wild-type or their semen for inclusion in the NAHYR.
Purebred Registration Criterion. The criterion for Purebred Status for The North American Yak (NAHYR) will include the following four (4) summary requirements as the core of its criterion.
1) Known Parentage: Genetically verified (95% certainty).
2) Hybrids Excluded: Maximum 5 cattle alleles (5%). Genetic testing with 95 SNPs at GeneSeek was designed by Dr. Ted Kalbfleisch and Dr. Mike Heaton USMARC to detect cattle introgression in yak (see Genetic Analyses below).
3) White yak are excluded: Genetic research has confirmed that white coat color in yak is a result of hybridization with cattle. For this reason, the phenotypic trait and/or expression of the genetic marker (PMEL) is grounds for exclusion from registration as a Purebred North American Yak (see Genetic Analyses and Yak Coat Color below).
4) No breed-back or “B-book” registration alternatives will be available. The Appendix B Progression Program was initiated by IYAK and subsequently a Generation Based Progression Registry. These were meant to introduce outside genetics into the Registry but later revealed that most Applicants were from degenerative multi-sire breeding groups and many drop outs from the NAYR (recycled lost pedigree animals). These registrations defeated the purpose of the programs and introduced the prospect of cattle introgression.
GEORGRAPHY
Original Tibetan Yak Distribution. Dr. Weiner discusses the specific areas of Western “China” that are of interest, provides a map, and gives geographic regions associated with each of the specific yak breeds. This geography is what was once called Tibet. These provinces are now called the Tibetan Autonomous Regions of the Peoples Republic of China. References by Weiner, G, 2014 and other academics to “Chinese” yak is, is an artifact of politics. Since 1959, Tibet has been a part of the Peoples Republic of China, and to date the UN has not acknowledged His Holiness Dalai Lama’s Tibetan Government in Exile.
“The area, as seen in Figure 1.1, extends from the southern slopes of the Himalayas in the south to the Altai in the north and from the Pamir in the west to the Minshan mountains in the east. The centre of the yak's distribution is the Qinghai-Tibetan Plateau (QTP), which is interspersed with several mountain ranges.”
- Weiner, G, 2014
North American Yak Distribution. There has been extensive, bi-directional trading between the US and Canada over the last 40 years. The pedigree of known Canadian and Alaskan herds do not indicate that they are differentiated as two independent breeds either phenotypically or genetically. Currently, no known yak populations are distinct based on geography alone. A cluster analysis on the WHYC/NAHYR Foundation yak was done to determine if inbreeding was occurring at a given ranch or in a given region. No meaningful genetic clusters were identified (Porter, 2019). The best candidate would be Alaska due to its geographic isolation, however little genetic data exists for this population. This could be explored further in future research. However, these data apply specifically to WHYC/NAHYR lineages and are not expected to apply to any given yak, based on geographic location and/or presence on this continent alone.
NAHYR Pedigree Distribution. Tables are being developed for the primary lineages contributing to WHYC/NAHYR. I’m currently in communication with Drs. Weiner and Han Jianlin, and awaiting reports from the Wildlife Conservation Society in New York in the form of Taxon reports. The Tables in Historic Yak Populations are preliminary WHYC/NAHYR lineages (version 1, Nov 21, 2020), and were compiled based on: ZIMS system contributions, TAG and individual zoo curators, historical reports of Lawrence Richards, and records of yak Historian, Diane Latona. They are also cross referenced with original documents, new paper articles, and photographic documentation when possible. However, these findings apply specifically to WHYC/NAHYR lineages and are not expected to apply to NA yak in general or based on geographic location alone (See Historic Yak Populations, Tables 1-5).
BREED COUNTS
One Breed (subsp. Bos or Bison mutus americanus). North American Yak are a likely a subspecies cross-breed of Bos grunniens (Linnaeus, 1766) and Bos mutus (Przewalski, 1883), which are the domestic and wild forms, respectively, of the bovid commonly called the yak. It has been acknowledged that phenotypically North American yak more closely resemble the Bos mutus subspecies (Weiner, G et al, 2014), and this has held even in NA settings with poor nutritional availability. New whole genome sequencing published this month by Han Jianlin finds that the DaTong yak is a new crossbreed between the domestic yak and wild yak subspecies (Zhi-Xin Chai, et al, 2020). Phenotypically NAHYR yak are very similar to the published dimensions of this new cross breed. This provides additional evidence that there is a genetic difference we are uncovering, and that the current research at University of Madison will provide a clearer picture of the similarities and differences of North American yak to Bos mutus and Bos grunniens.
Several papers have indicated that the Tibetan yak is more closely related to bison than cattle (Qui Q, 2019). Dr. Han Jianlin in his 2014 chapter on Wild yak states: "Hassanin et al. (2013) concluded that the genus Bison should be regarded as a synonym of Bos, with the European bison relegated to a subspecies rank within Bos bison as B. bison bison. If this proposal holds true, wild yak could only be justified as a subspecies in Bos grunniens mutus of domestic yak Bos grunniens.” If UW Madison’s work replicates these findings, we may be looking at a Bison grunniens americanus (or something similar).
Based on our known WHYC/NAHYR pedigree and the extensive bi-directional movement of yak throughout North America (Canada vs. US), differentiation of WHYC/NAHYR breeds will likely be difficult. However, we can be confident that NAHYR does not currently contain cross-species hybrids. WHYC/NAHYR will likely most closely resemble Bos mutus, however, it will likely be a new subspecies type (which, for convenience, I currently call: Bos mutus americanus).
The degree of genetic similarity to the “wild-type” yak (Bos mutus) will determine the international significance of WHYC/NAHYR. Ongoing research by the Yak Genotyping Team (Kathib, Porter and Urbano Braz) will attempt to confirm these preliminary results and address these questions. However, these findings apply specifically to WHYC/NAHYR lineages and are not expected to apply to any given NA yak based on geographic presence on the continent alone.
Three (3) Breeding Lines. There are three breeding lines in the United States. The three lines are the offspring of 3 unrelated breeding bulls. The WHYC/NAHYR herd book commonly goes back 5-7 generations and are recorded in our database (n ≈ 1200). All of the Foundation animals have been genetically tested and their pedigree confirmed using several types of genetic data.
Table 2: Woburn Line (merged with Toronto Phenotype):
Table 3: Toronto Phenotype (Queen Allante Line: Prince Allante/Escalade/Alaska)
Table 4: Lock Phenotype (Dreadlock Line/Dr. Lock/Infinity)
Table 5: Royal Phenotype (Senior Diamond/Jr. Diamond)
Hundreds of Breeding Cows. There are more than the required number of breeding females prescribed by The Livestock Conservancy (n= 20) in the North American Yak herd. We estimate that there are currently between 600-1100 purebred, pedigreed breeding cows in the United States that would meet the proposed criterion by The World Heritage Yak Conservancy (WHYC).
Dozens of Breeding Ranches. There are more than the required number of breeders prescribed by The Livestock conservancy (n= 5) at different locations in the United States. There are currently thirty estimated (n≈ 27-32) independent breeders in the US that are practicing selective breeding and Best Practices (ranches breeding hybrids or with multi-sire, mixed herd breeding practices are not included in this count).
GENETIC ANALYSES
Six Types of Genetic Data utilized by WHYC for NAHYR. There are currently 6 recent bodies of data that are used to verify purebred yak for registration. However, these data apply specifically to WHYC/NAHYR lineages and are not expected to apply to a given NA yak based on geographic location alone.
1) Ancestral vs. Recent Cattle Introgression. We currently have the ability to differentiate Recent vs Ancestral cattle introgression (Kalbfliesh, T., et al, 2020). This data will be employed to determine purebred status for the WHYC/NAHYR. This assessment indicates that little introgression (Herd level <.06%) has currently occurred in the NAHYR purebred, foundation population (Porter, 2019).
2) Specific Hybrid Markers for Coat Color. Several specific genetic markers (n = 4) have been identified that indicate recent cattle hybridization (Petersen, J., 2019, Kalbfliesh, T., 2020). These alleles will be used to determine purebred status for the North American Heritage Yak Registry (NAHYR) (eg. Charolais, Highland, etc.), and are successful at excluding hybrids (See additional content for details below in Question #8).
3) Cattle Introgression. A big surprise from my preliminary data from 95 SNPs (n ≈ 2100) is that the WHYC/NAHYR is less introgressed than domestic yak on the Qinghai-Tibetan Plateau (QTP) (Herd level Cattle Introgression: 0.637, or < 1 cattle allele in 95). Preliminary data, based on 95 SNPs, suggests that our WHYC/NAHYR foundation herd has less cattle introgression than Bos grunniens on the Tibetan Plateau, and NAHYR more closely resembles Bos mutus on this variable (Porter, N., 2018). However, more research from direct comparisons is recommended from a larger genetic sample. Ongoing research by the Yak Genotype Team at the University of Wisconsin Madison will attempt to validate these findings.
4) Coefficient of Inbreeding (COI). Another surprising finding, based on 95 SNPs, suggests that our WHYC/NAHYR foundation herd has less inbreeding than Bos grunniens on the Tibetan Plateau. Our herd level COI is quite low (0.014), which could also indicate that WHYC/NAHYR more closely resembles Bos mutus on this variable as well (Porter, N., 2019). However, more research from direct comparisons with a larger genetic sample is recommended.
Some inbreeding is now appearing in the offspring of some purebred Foundation animals, with some pedigreed calves coming in at .175, and one as high as 0.30 in 2020. I have raised questions about the validity of the current SNPs, and 2 Program evaluations have been preformed (Porter, 2019, Petersen 2020). There is an opportunity to improve COI calculations by removing and replacing poorly performing SNPs to increase validity on this measure. However, we will still need to find and introduce some unique genomes to these influential line breeders, since the 3 main breeding lines are no longer distinct. There is strong evidence that divested zoo animals could bring new, quality diversity to the WHYC/NAHYR herd.
5) Parental Verification. A comparison of 95 SNPs from the Dam and Sire are compared to the SNPs presented in the offspring. If there is a match on 95% of the markers, parentage is considered verified. This process is not used for “parental identification” for offspring of unidentified/unknown parentage.
6) Geographic Cluster Analyses. Cluster analyses on the WHYC/NAHYR Foundation yak were preformed to determine if inbreeding was occurring at a given ranch or in a given region. No meaningful genetic differences were identified. This indicates that Canadian and US genetics have effectively merged into one breed.
YAK COAT COLOR
Color Inheritance of the North American Yak was first delineated in a series of articles by Lawrence G. Richards. At first a mere projection, his inheritance theory has been borne out by 30 years of observed yak breeding in North America. In reality it is actually pattern inheritance not color inheritance. North American Yaks have 3 patterns: Royal, Trim and Solid.
Richards predicted that Royals are homozygous for the piebald pattern, Trims are heterozygous and express as a partial expression of the pattern trait (as roan coloration in beef cattle). The inheritance follows simple Mendelian genetics and the precision of the inheritance supports the position that the North American Yak is indeed a true breed. Any hybridization with cattle would disrupt this inheritance pattern. Discovery of this theory laid the groundwork for our modern genomic based scientists to verify the underlying genetics. See Yak Coat Color section Code Book Kit. Royals (TT) Homozygous, Trims (TC, CT) Heterozygous.
The colors seen in North American Yaks are Native Black (IYAK nomenclature) grey nosed with grey dorsal stripe and Imperial which are coal black at birth with a black nose. Imperials exist in 2 subsets: The super wooly which typically have more of the reddish cast and the shiny Imperials which have a jet black shiny coat with silky guard hair which allows the luxurious undercoat to be easily groomed out (higher harvestability).
Imperials are either homozygous Imperial or heterozygous Imperial. A heterozygous Imperial can be predicted by pedigree analysis( Imperial born from either a Native Black Sire or Dam) and verified by production ( a Heterozygous Imperial will produce a mixture of Imperial and Native Black offspring). The only 2 proven Homozygous Imperials are LDR DR. LOCK O086 and his son FW STETSON T029. Bred to Native Black or Royal females these 2 bulls have produced over 130 Imperial or Imperial Trim (from Royals) offspring with no exceptions (Native Black offspring). The genomics of this has not yet been properly studied. Dr. Penedo at UC Davis declared that the black seen in DR.LOCK is not cattle black(e). The third color Golden is a recessive trait recessive to Imperial. It is not a true golden as seen in golden palomino horses in the American Quarter Horse breed, hence the name is a misnomer.
White Yak on the Qinghai-Tibetan Plateau. There are several studies demonstrating that white yak are cattle hybrids. One study found that both sub-species (Bos mutus and Bos grunniens) are more similar to bison than the Tianzhu white yak breed found in the Tianzhu region of Tibet-China (Bai, J, et al., 2015). This was replicated by additional direct genetic comparisons, indicating that the Tianzhu white yak genome is more similar to the cattle species (Bos taurus) than any yak subspecies (Bos mutus or Bos grunniens). They also determined that identifiable cattle mutations are responsible for creating the white coat color (Qui, Q, et al. 2012, 2015). Recent work by Han Jainlin in Nov 2020 says “the white hair of Tianzhu yak is produced by long-term artificial breeding.” This is important because no research has yet identified any white yak that are not a result of cross-species hybridization with cattle (Bos taurus or Bos indicus). We currently assume that these regulations prohibiting hybridization will will be employed by WHYC.
WHYC Code of Ethics: “For a WHYC member to knowingly misrepresent an Applicant (of any color) from a hybridization program will be considered a violation of the Code of Ethics resulting in immediate and irrevocable termination of WHYC membership.”
White Yak Charolais Allele. Dr. Pendeto
Recently Dr. Jessica Petersen has identified the specific allele that contributes the dilution gene in white yak (Petersen, 2019). It is a mutation for the Charolais dilution phenotype (Bos taurus). This genetic marker has been tracked throughout the WHYC/NAHYR, and in every case the white yak (n=23) carried the Charolais dilution marker (Porter, 2019). There is currently no evidence that any white yak can be considered a purebreds on any continent. No yak with the Charolais cattle dilution marker will be eligible for registration at WHYC/NAHYR.
WHYC/NAHYR Code Book: PMEL 1 (Dc) chr5: If A (Including AA or GA): “Cattle Dilution allele is present.” Any other alleles indicate: “No Dilution allele present.” This change in the shows replacement 22 glycine (allele c.64G) by arginine (allele c.64A). This is a dominant gene. PMEL 1 is acknowledged as a breed specific Charolais dilution gene at UC Davis under RTM testing, and was verified by SNP testing at University of Nebraska with Neogen’s GeneSeek.
Golden Yak Highland Allele. Similarly, to the Charolais marker, recently Dr. Jessica Petersen has identified the specific allele that contributes the color gene in golden yak (Petersen, 2019). It is a mutation for the Highland phenotype (Bos taurus). This genetic marker has not yet been tracked throughout the WHYC/NAHYR. However, there is currently evidence that a golden coat color in yak can be expressed in purebreds by other mechanisms (eg. copper deficiency, recently discovered golden-brown genotype in Qiangtang etc.), and are not always indicative of Highland introgression. No yak with the Highland cattle dilution marker will be eligible for registration at WHYC/NAHYR.
WHYC/NAHYR Code Book: PMEL 2 (Dh) chr5: ttcttc: “Highland Cattle Dilution allele present.” Any other alleles indicate: “No Highland Cattle Dilution allele present.” This is a Highland Breed Specific marker and is a recessive gene. PMEL 2 was previously reported as “dilution allele present” on the WHYC/NAHYR Genetic Report. However, this Highland breed specific SNP marker was recently published and should be reported as such.”
Trims. Trims typically display a white star or stripe on their forehead. Rear legs, and sometimes all four legs, have white socks and 1/3 to 1/2 of the tail may be white (Richards, 2014). Research suggests that this is Ancestral cattle introgression dating back 7500s of years (Kalbfleisch T, et al, 2020). We have also seen full white tails and white dorsal stripes in Trims, which is considered an original ancestral remnant (Wiener, G. 2014). The amount of white does not determine if the animal is a Trim; even a small expression of white qualifies the animal as a Trim. Since, white markings are currently considered an Ancestral cattle marking or a Bos mutus artifact, Trims are considered appropriate for NAYR registration as a purebred.
WHYC/NAHYR Code Book: KIT: TT: “Non-modern (Ancestral) cattle allele present - Royal (homozygous)” We currently have new data that this marker is not representative of modern domestic cattle. TC, CT: “Coat pattern allele present - Trim (heterozygous)” CC: Original Yak Black, Other: “No Cattle allele present” This marker has now been validated and the paper published (Petersen, 2019).
Fiber. We are currently reporting on one fiber marker that suggests that short fiber is associated with Recent cattle introgression. This will be verified in future research.
WHYC/NAHYR Code Book: FGF5: TT: “Long Hair Length Angora allele present (homozygous)", AA: "Short hair type present” Other: “Long Hair Angora allele not present.” Short hair type is a cattle-specific marker, data not published.
Multiple Breed Associations. There are currently 2 association of breeders in the United States, North America, or abroad. These are the International Yak Association (IYAK), which is the mother organization to the North American Yak Registry (NAYR), and the United States Yak Association (USyak). The overall policy trends of these associations have shifted away from preservation in recent years. On the contrary, these associations are currently supporting genetic degradation (ie. hybridization, multi-sire, mixed-herd breeding practices, etc.). Since we began writing this Proposal, it was announced that IYAK will now begin registering hybrids and unpedigreed stock as part of their Foundation herd. There is an urgent need for a group to fill the gap, collect serious breeders, protect pedigree and preserve the integrity of the yak genome.
With the help of the Livestock Conservancy, we are currently considering creating an umbrella organization to “Preserve, Promote, and Protect” the North American yak herd. We would accomplish this by upholding rigorous registry criterion based on genetic testing, and by supporting ongoing breed selection practices for genetic integrity, as well as longevity, fertility, and productivity.
Our team is made up of founding IYAK members, past presidents and recently resigned board and committee members. Our team includes all 3 premier pedigreed ranches, and the support of the important breeders in the US. Our goal is to return to the criterion previously upheld by IYAK (eg. strict breeding “Best Practices”, prohibition of cattle introgression, requirements of low COI, the elimination of all “breed back’ programs, etc.). A working title for this association is: The World Heritage Yak Conservancy (WHYC) (www.twhyc.org) and the North American Heritage Yak Registry (NAHYR).
Contributing to the Yak’s Survival Internationally. The same anthropogenic effects occurring in the US are in play world-wide (Shi, Q., et al, 2016). The non-United States populations of Bos mutus yak are at risk both geographically (due to loss of nomadic grazing land) and politically (due to hybridizing and poor breeding practices) in Tibet-China, Mongolia, Pakistan and Canada, as well as the US. The predominance of interbreeding with cattle (Bos tarus) and domestic yak (Bos grunniens) is identified as the greatest threat to Bos mutus populations by many conservationists (Buzzard, et al., 2014). The degree of genetic similarity of NA yak to the “wild-type” yak (Bos mutus) in Tibet-China, will determine the potential international significance.
The North American Yak herd, comprising the United States population, is a unique True Genetic Breed and remnant genome, and if preserved could become reciprocal to other populations in the future. The risk to local (North American Yak pedigree) and global (degradation of the species) is a clear and present danger. Taking-action now to preserve breed integrity, means this registry would be preserving a remnant of globally and nationally threatened populations due to human mismanagement.
Thank you for your consideration.
Best,
Nicole Porter PhD and Daniel Salvato, Livestock Conservancy, IYAK past-BOD, Genome Committee Chair, Membership Committee
Lawrence Richards, IYAK founder, past-VP, Genome Chair, Lifetime member
Jandy and Brad Sprouse, IYAK past-President and Life time members
Steve and Anita Hill, Livestock Conservancy members, IYAK past-BOD member, Lifetime members
Selected Bibliography
Berger, J., Cheng, E., Kang, A., Krebs, M. et al (2014-06-26). "Sex differences in ecology of wild yaks at high elevation in the Kekexili Reserve, Tibetan Qinghai Plateau, China". Journal of Mammalogy. 95 (3): 638–645. doi:10.1644/13-MAMM-A-154. ISSN 0022-2372.
Buzzard, P. & Berger, J. (2016). "Bos mutus". IUCN Red List of Threatened Species. 2016: e.T2892A101293528.
IUCN 2020. The IUCN Red List of Threatened Species. Version 2020-2. https://www.iucnredlist.org. Downloaded on 09 July 2020.
Kalbfleisch T, Petersen JL, Tait Jr. RG et al. (2020) Using triallelic SNPs for determining parentage in North American yak (Bos grunniens) and estimating cattle (B. taurus) introgression [version 1; peer review: 1 approved, 1 approved with reservations]. F1000Research 2020, 9:1096 (https://doi.org/10.12688/f1000research.25803.1)
Petersen, JL; Kalbfleisch, T; Parris, et al (2019) MC1R and KIT Haplotypes Associate With Pigmentation Phenotypes of North American Yak (Bos grunniens) The Journal of heredity 111(2) DOI: 10.1093/jhered/esz070
Porter, N. (2019). Current Developments in genetics of North American Yak Registry: A survey of yak in North America. Proceedings of animal nutrition and ecology research, Xining, China, 12-14 September 2019. Qinghai Academy of Veterinary Medicine and Animal Science, Qinghai University, pp. 4.
Qiu, Q. et al. Genomic data from the domestic yak (Bos grunniens). GigaScience Database. https://doi.org/10.5524/100071 (2013).
Qiu, Q. et al. (2015) Yak whole-genome resequencing reveals domestication signatures and prehistoric population expansions. Nat. Commun. 6, 10283.
Richards, L (1991) New Yak Times Vol. 1, No.1 ,Sept. 21
Richards, L (2015) The Grunting Ox Vol 1, No. 1, Oct 10, 2015
Richards, L (2010) IYAK Website, 0ct. 15, 2010
Schaller, G. B. & Liu, W. (1996) Distribution, status, and conservation of wild yak Bos grunniens. Biol. Conserv. 76, 1–8.
Schaller, G. B. Kang, A., Hashi, T.D. & Cai, P (2007) A winterwildlife survey in the northern Qiangtang of Tibet Autonomous Region and Qinghai Province, China. Acta Theriologica Sinica, 27, 309–316 (7)
Seton, E.T. (1909) The Yak—A North American Opportunity”. Country Life in America.
Shi, Q, Guo, Y., Engelhardt, S., Meng. X. (2016) Endangered wild yak (Bos grunniens) in the Tibetan plateau and adjacent regions: Population size, distribution, conservation perspectives and its relation to the domestic subspecies. Journal for Nature Conservation 32. DOI: 10.1016/j.jnc.2016.04.001
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.
Weiner, G. (2014) The Yak in Relation to its environment. Bangkok, Thailand: Regional Office for Asia and the Pacific Food and Agriculture Organization of the United Nations. ISBN 9251049653.
Zheng P.L. (ed). 1985. Chinese animal breeds and their ecological characteristics. Agricultural Press, Beijing, P.R. China. pp. 45–59. [in Chinese].
Zhi-Xin Chai, et al (2020) Whole-genome resequencing provides insights into the evolution and divergence of the native domestic yaks of the Qinghai-Tibet Plateau, BMC Evolutionary Biology 20:137 DOI: 10.1186/s12862-020-01702-8