- The breeding season of yaks has reportedly shifted from June/July to September. The reproductive performance of yak is closely related to climate and season, say veterinary scientists.
- Grasslands are degrading, temperatures are rising, rainfall is erratic, and invasive alien plant species are taking over pasturelands. These factors have an overall impact on the yak population.
- There has been an almost 25% decline in yak population in India between 2012 and 2019.
- Experts say a transboundary regional approach is needed to exchange yak germplasm and save the highland species.
A steep climb from Namche Bazar, a village of the Indigenous Sherpa community, leads to the undulating grasslands of Syangboche in the Everest region of Nepal. Right in the middle of the patan (grassland), at an altitude of 3,885 metres above mean sea level, is the stone and tin-shed structure that is the Yak Genetic Resource Centre.
The grassland around the resource centre, which comes under the Nepal government’s Ministry of Agriculture and Livestock Development, is fenced with a barbed wire mounted on a low cemented wall. It is early May and a herd of domesticated yaks (Bos grunniens) and their calves are grazing meditatively.
“Yaks are the lifeline of this region. The centre has about 155 yaks and we conduct research and maintain a high variation in the genetic makeup of this high-altitude species, commonly found in the Everest region,” Ramlallan Yadav, technical officer at the Yak Genetic Research Centre for 24 years, tells Mongabay India.
Yadav says climate change is closely linked to the state of the yak population. “For the past 10-11 years, there has been a shift in the breeding season of yaks. The mating season was in the months of June and July, but that has now shifted to September,” he says.
The mating season depends on the availability of grasses and nutrition for yaks. But the grasslands are getting degraded and encroached, temperatures are rising, and rainfall patterns are erratic. There has also been an increase in invasive alien plant species. Yadav fears that climate change has impacted the breeding and well-being of the yaks.
“Earlier, we used to get soft rains, but now we receive bursts of heavy rainfall. Thunderstorms were rare, but now we have many intense storms. Snowfall patterns have changed, too. Earlier, it snowed between September and February, but now it snows as late as February and March,” he points out.
The yak population is on the decline in the Himalayan highlands, including the Indian Himalayan Region. Experts say the changing breeding season will make things worse for the yak.
Over 500 kilometres east of Syangboche as the crow flies, lies the Government of India’s National Research Centre on Yak in Dirang, Arunachal Pradesh. It comes under the Indian Council of Agricultural Research (ICAR). ICAR-NRC is the sole authority on research strategy formulation for the sustainable development of yak husbandry in the country.
Senior Scientist Sapunii Stephen Hanah has worked at ICAR-NRC and co-authored a research paper on yaks in the northeastern Indian Himalayas. He tells Mongabay India, “Yak herders and farmers in the high-altitude areas of Arunachal Pradesh have reported a shift in the breeding season of yaks, which might be due to climate change. However, this shift has not been observed at the ICAR-NRC Yak farm. The institute’s farm, located in Nyukmadung, operates under a semi-intensive system with all necessary facilities for optimal animal production, such as sufficient feed, fodder, and water throughout the season, which are crucial for the animals’ health. In contrast, nomadic yak herders face significant challenges in providing feed and fodder, especially during the winter season.”
Under field conditions, yaks are seasonal breeders. “From April onwards, green fodder starts to become available in highland pasturelands, leading to an improvement in the health of yaks. As their health improves, female yaks, known as nak or dri, begin to ovulate, and the breeding season starts. The breeding season reaches its peak in July and August when temperatures are at their highest and grass growth is at its best. In winter, the availability of fodder drops significantly, as everything is covered in snow, causing yaks to lose body weight,” Hanah explains.
Yak, a flagship species
The yak is specially adapted to a high-altitude environment and is a flagship species for the Hindu Kush Himalayan (HKH) region. It is usually found 3,000 – 6,000 metres above mean sea level and survives in extremely cold, harsh environments with low atmospheric oxygen concentrations and high levels of solar radiation.
The animal plays a key role not only in agrobiodiversity conservation and maintaining the high rangeland ecosystem, but also in cultural traditions, livelihood strategies, and socioeconomic development in the high mountain areas of the Himalayas, notes ICIMOD, International Centre for Integrated Mountain Development.
Yaks are raised primarily for meat and milk. Milk is used for products such as butter/ghee and dry and hard curd cheese (chhurpi), which are mainly sold and also used for home consumption and for making ‘salty butter tea.’ Yak wool is used to make rope and tents. Yaks are also used as pack animals, as they can travel up to 15 km per day in high-altitude areas carrying loads of up to 100 kg in weight.
Yak population on a decline
There is a lack of precise data on the current population of domestic yaks, but estimates put it at around 13–14 million, with the majority of them in China.
“Outside China, the domestic yak populations are declining in many countries, e.g., India, Bhutan, and Nepal. In addition, increasing hybridisation has made it difficult to identify the pure domestic yak population,” states an August 2022 research paper.
In India, official data shows a decline in yak population. As per the 20th Livestock Census of the Government of India, which was released in 2019, there has been an almost 25% decline in yak population in the country. The yak population has dropped from 77,000 in 2012 to 58,000 in 2019. Male and female yak population has dropped from 35,000 to 26,000 and 42,000 to 32,000 in the same time period, respectively.
Jammu and Kashmir, which has the highest yak population in the country, has registered the sharpest decline. Meanwhile, Arunachal Pradesh and Sikkim in northeast India have shown an increase.
Yaks are increasingly coming under pressure due to a number of factors including closed international borders that restrict the mixing of their gene pool, degrading pasturelands, restrictions on grazing and movement of the animals, and climate change.
The worst calamity happened in the winter of 2019 when hundreds of yaks starved to death in Sikkim, says Hanah. According to ICAR-NRC’s Annual Report 2019, unprecedented natural calamities and continuous heavy snowfall have led to more than 500 yaks dying in North Sikkim.
Shanker Raj Barsila, an Associate professor at Agriculture and Forestry University in Chitwan, Nepal, reiterated why the yak population was on the decline.
“The forage productivity and availability, and the local weather conditions, such as timely rainfall during onset of spring, are the most important factors,” says the expert on high-altitude pastoralism and grazing ecology.
“The yak is a domesticated animal with some wilderness in habit. It is a typical seasonal breeder. Feeds and nutrition are important for breeding, and timely precipitation maintains the health of the pasturelands. However, grasslands are degrading, and there is additional grazing overlapping pressure from mountain sheep and goats,” says Barsila.
Hanah agrees. “The younger generation is unwilling to continue with traditional yak herding, which is extremely difficult because it relies on transhumant pastoralism,” he says.
Transhumance is the seasonal movement of livestock and is the most prevalent practice in the pastoral communities of the Himalayas. Yaks migrate seasonally between winter and summer pastures at different heights.
In the traditional seasonal migratory system, the alpine pastures (4,500 m and above) are grazed between June and September. The middle hills (3,500 – 4,500 m) are grazed from March to May as the animals migrate up to the high pastures and again on their return during October and November. The winter (December to the end of February) is then spent on grazing below 3,000 m.
“Beginning April, yak farmers of Arunachal Pradesh, known as Brokpa, start moving their yaks from winter pastures to summer pastures. This period marks the start of the calving and milking of the animals. The yak’s body condition improves due to the availability of fresh grass along the transit route,” says Hanah, who is currently posted at the ICAR-National Research Centre on Mithun in Nagaland.
He goes on to explain that during summer, from May to September, the yaks stay in the alpine pastures. “By autumn, which is in October-November, they move down to lower altitudes or village grasslands, transitioning from summer pastures to winter grazing grounds,” he says.
Despite this migration, from October to March, feed shortages are common due to thick snow layers over the winter pastures. Inadequate forage, especially in winter, leads to poor nutrition, slow growth, health-related problems, and reduced fertility, says an ICIMOD report, Yak On The Move. In many yak-raising areas, these problems are exacerbated by increasing livestock numbers, which places greater pressure on rangelands and leads to overgrazing.
“Though this transhumance pastoralism system has been practiced for generations, the younger generation does not support their parents in this tradition. As a result, the number of yaks and herdsmen are declining,” says Hanah.
Climate change is making it worse
Yaks are extremely well adapted to intense cold. They can survive ambient temperatures of minus 40°C and perform best when the average annual temperature lies below five °C and the average temperature in the hottest month is less than 13°C. Rising temperature and changing rainfall patterns are affecting breeding in yaks and also their productivity.
Based on data from 478 meteorological stations across the Hindu-Kush Himalayan region collected between 1961 and 2015, a study published in 2022 had claimed that there had been a significant decrease in the number of extreme cold events (cold nights, cold days, and frost days) and a concomitant increase in the number of extreme warm events (warm nights, warm days, and summer days). Similar trends have been reported in the western Himalayas as well.
The study says yak reproductive performance is closely related to climate and season. “The start and end of the breeding season are determined by ambient temperature and relative humidity… The timing of the breeding season has a close relationship with factors that determine climate, i.e., the latitude, longitude, and altitude of the pastures where yak are kept,” it says.
“In the past 10 years, I have come across people claiming that yak breeding is getting postponed by up to two months now,” says Barsila.
Yak On The Move states that climate data available from the region suggest an increase in temperature, which is greater at higher elevations. “Warming temperatures in the high elevation region can have a negative impact on yak populations because of their lack of tolerance for heat. The reduction in habitat could be associated with a decline in yak survival and/or reproduction,” the report observes.
Temperature changes have also meant that high-altitude, cold-adapted plant species have shifted to higher altitudes and have been replaced by species that are better adapted to warmer temperatures. These changes have resulted in alterations in vegetation type, with alpine meadows and herbs being replaced by shrubs. Shrub encroachment is probably the major climate-change-associated factor decreasing the availability and quality of grazing vegetation in the Himalayas.
Few studies link rising temperatures with heat stress in yaks and reduced milk yield. Hanah acknowledges that very few research organisations are working on the yak and supporting yak herders.
Need of the hour
Yadav of Yak Genetic Resource Centre in Syangboche pointed out the institute’s lack of budgetary support. “Yaks are in danger, and there is a lack of funding,” he says.
According to Barsila, yaks are a low-priority commodity for the national government as these animals are limited to 16 highland districts of Nepal and are not herded by many households. The overall contribution of yaks to the national economy is negligible, and hence, they are not a funding priority.
Though yaks are culturally, socially, and economically linked to the tribes of high-altitude regions, farmers face many challenges in maintaining their herds, says Hanah. “To support the farming community, the government, NGOs, and private sector organisations working for the welfare of yak farmers should provide financial assistance and subsidies. Additionally, regular training and education on scientific management systems, protection and restoration of pasturelands, improved veterinary services, and market development and access should be urgently implemented,” he adds.
In Arunachal Pradesh, efforts are being made to link yak herders with banks and make loan facilities available to them. The yak has also been designated as a food animal by the Food Safety Standard Authority of India (FSSAI), which is likely to help yak herders. Prior to this approval, yak milk and meat were not part of the conventional dairy and meat industries.
To save the highland species, there is a need for a transboundary approach, says Barsila. Nepal, India, and Bhutan – which share the transboundary Kangchenjunga landscape in the eastern Himalaya – have been connected through the culture of yak herding and the yak economy for centuries, notes ICIMOD.
However, herding communities in the region also face isolation, low productivity due to inbreeding, and market challenges, leading to a decrease in yak herding and interest in the same across the landscape. The Last Dokpas of North Sikkim has documented the impact of the closing of the international border between Tibet and Sikkim on the lives of Dokpas – ethnically Tibetan high-altitude nomads – who used to migrate seasonally with the yaks that they herd.
Through the Kangchenjunga Landscape and Conservation Development Initiative (KLCDI), ICIMOD has chosen yak as one of its thematic intervention areas. It says partners from Nepal, India, and Bhutan have unanimously endorsed the need for exchanging yak germplasm to harness the benefits of transboundary cooperation.
Yak does not understand imaginary lines and international boundaries on the world map. Countries need to come together to protect the highland species.
Reporting for this story has been as part of the Himalayan Climate Boot Camp 2024 organised by Nepal Forum of Science Journalists.
Banner image: Yaks transporting essentials to Everest Base Camp. These animals play a key role in agrobiodiversity conservation, maintaining high rangeland ecosystems, cultural traditions, livelihood strategies, and socioeconomic development in the high mountain areas of the Himalayas. Image courtesy of Chencho Dema.
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