Researchers aim to boost nutrition in Tibet
For the past two years, Murdoch University researcher Nicole Spiegel has been working with a team of scientists in Tibet on a project funded by the Australian Centre for International Agricultural Research (ACIAR).
ACIAR began working with researchers in Tibet in 2004. The project that Nicole — and Murdoch University — has been working on aims to stabilise the condition and improve the nutrition of sheep, yaks, cattle and goats through the year by boosting mineral intake.
These animals are relied on for their milk and fibre, and an increase in dairy production is needed for both local consumption and to meet the demands of tourism.
Just as Westerners love a daily cup of coffee, the Tibetans love nothing more than a cup of hot butter tea. It’s a concoction of loose leaf tea, boiled and filtered, which is then blended with a small amount of yak butter and salt to taste.
“It’s just like drinking salty, hot butter. It sounds horrible, but I enjoy drinking it and it probably helps me deal with the high altitude,” Nicole said.
Tibet’s dairy industry is in the early stages of development and is dominated by subsistence farming.
Cows produce an average of five litres of milk a day, which is mostly used in the home, with a small amount left over for sale.
A small producer will have, on average, three to five cows and farm one to two hectares.
In WA, cows produce an average of 20 litres a day, the milk is sold to dairy companies and the average dairy farm is more than 235ha.
But a poor feed base, harsh winters and high spring mortality have an impact on the nutrition of Tibet’s milking animals, as well as those who consume the milk and its by-products.
Most of Tibet is similar to the pastoral regions of Australia in the sense that it is dry, barren and fragile, but the landscape differs because of the higher altitude and mountainous terrain.
Trees do not grow in the high altitudes, much of the land is wind-swept and winters are severe and long. Temperatures start to drop in autumn (as early as September/October) and the cold continues into spring (as late as April/May).
Tibet’s central cropping area offers the greatest potential for intensive farming. It comprises a network of river valleys where improved cropping can be matched with adequate summer moisture and solar radiation.
For the health of livestock, it is a never-ending cycle that follows the seasons.
In summer, animals put on weight from grazing the surrounding mountains, but this gain is limited.
For example, it is common for dairy cows to be tethered to a spot and only offered limited amounts of supplements, such as crop residues and by-products like barley meal, brewer’s grains and rape meal.
In early autumn, livestock are in their best condition, ready to endure the cold months that lay ahead.
However, in winter when feed on offer is non-existent and the ration is replaced with poor-quality straw that has often been left to the elements, the livestock lose condition and their health deteriorates.
“Yaks, for example, can lose up to 20 per cent of their body weight during winter,” Nicole said.
“Come spring, there are high mortality rates and if they survive the spring, the cycle continues again.”
By including mineral supplements through the winter and summer, researchers are hoping to improve the health of Tibetan livestock.
“In summer, we are looking at trace elements that will maximise growth and performance,” Nicole said.
“In winter, we want to provide major minerals the animals lack and give them a bit of energy and protein to minimise weight loss.
“Hopefully, they will be healthier, avoid the spring mortality and their rumen will be ready for the green grass at the end of spring and into the early summer.”
To get an insight into the mineral status of Tibetan livestock, researchers collected and tested blood, urine, milk and dung samples from sheep, cattle and yaks and from pasture and feed supplements in summer 2009, autumn 2009, winter 2003 and spring 2004.
Production losses resulting from selenium deficiency can include ill thrift in young animals, poor growth rates, infertility, reproductive disorders and compromised immune function.
Copper deficiencies can lead to poor growth, infertility and lowered wool production, and iodine deficiency can reduce thyroid function, causing poor growth and development.
“The initial interest in the area of mineral deprivation in livestock in Tibet stemmed from evidence of mineral deficiencies in Tibetan people,” Nicole said.
The most severe cases recorded included iodine deficiency disorder, cretinism and Kashin-Beck disease (KBD). Known as ‘big-bone disease’ in humans, KBD is caused by a lack of iodine and selenium and results in stunted growth and joint deformity.
“Last year, we started administering yaks and dairy cattle with intra-ruminal selenium pellets and copper capsules and injecting iodine, and these animals will be tested again this year,” Nicole said. “Once the results are processed, we can see how well the supplements worked.”
By introducing minerals into the diets of Tibetan livestock, researchers are hoping it will also open the door for a new industry for rural areas.
“This year, we want to engage with the locals and start sourcing local ingredients to make mineral salt blocks and it will form the basis of another industry,” Nicole said.
It is hoped that the flow-on benefits from improving the health of Tibetan livestock will result in an increase in trace elements in the human food chain.
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