Zopkio

The zopkio (also dzopkio, zokio, dzokio, zopkyo, dzopkio) is a hybrid animal offspring of a yak and an ox [cite book|last=Chester|first=Jonathan|title=The Young Adventurers' Guide to Everest: From Avalanche to Zopkio|publisher=Tricycle Press|date=2005|isbn=1582461511] . The females are fertile, while the males are sterile. Females are also called zhum [ [https://dart.columbia.edu/haimendorf/glossary.html Glossary] ] .

The best information I've come across about yak,nak, zopkio and zhum is from Stanley Stevens. "Claiming the High Ground: Sherpas, Subsistence, and Environmental Change in the Highest Himalaya". Here is a text block from the source on-line:

"The crossbreeds that are bred in Khumbu from nak mothers and Tibetan bulls display a combination of traits reflecting their parentage. In general they differ from yak in size, coat, and their lesser fitness in extreme high-altitude conditions (particularly in winter). The males, known as dimzo (or dim zopkio ), are highly valued as draft and pack animals whereas the females, known as dim zhum (or dzum ), are considered excellent milch stock. [9] Fürer-Haimendorf reported that zhum yield more milk per lactation than nak, although it is not as rich. According to his information Khumbu crossbreeds produce about ten kilograms of butter per year per head compared to the nak's seven kilograms per year per head. [10] Crossbreeds herded in Shorung were said to yield twice as much butter as those pastured in Khumbu (Fürer-Haimendorf 1975:50). It should be noted, however, that higher milk yields for Khumbu zhum compared to Khumbu nak may reflect differences in fodder feeding and the relatively greater parts of the year that the zhum are herded in the lower-altitude areas of Khumbu. Zhum could not survive, much less yield large amounts of milk, in the conditions in which nak live.Tibetans have long practiced yak-cow crossbreeding. Tibetans along the eastern fringe of the Tibetan culture region, for example, gave such crossbreeds in tribute to the Tang emperors of China (Schaffer 1963:74). In some parts of Tibet, however, crossbreeding is not conducted due to a belief that the forced cross-species mating is offensive to local gods such as yul lha and lu. [11] The Tingri region just to the north of Khumbu is one of the areas where crossbreeds are valued and used, but are not bred. This has provided Khumbu herders with a major market for crossbreed dimzo calves and a complex trade developed in them still continues today on a limited scale. Dim zhum, considered finer milk producers than nak, although less hardy, have long been sought after by Shorung Sherpas and in the past twenty years have begun to be kept by Khumbu Sherpas in large numbers to provide family milk supplies.In recent years a third form of crossbreed has been important in Khumbu. This is the urang zopkio , the male offspring of lower-altitude pamu or palang pamu (Bos indicus ) cows and yak. Urang zopkio are not bred in Khumbu, but are purchased at considerable expense from lower-altitude areas including Shorung, Kulung, and Pharak. They have become important in Khumbu as plow animals and especially as a source of pack-stock income from tourism. [12] Their value in trekking work reflects the importance of the airstrip at Lukla as a tourist entrance to the area. Sherpas do not like to take yak down into the low-altitude reaches of the Dudh Kosi gorge in order to reach the Pharak airstrip. But they have no hesitation in taking the low-altitude-fit urang zopkio to Lukla, and the crossbreeds are also capable of making the haul through Khumbu to the foot of Mount Everest. The increase in the number of zopkio since the mid-1970s has been the most spectacular recent change in Khumbu pastoralism. By 1984 18 percent of all Khumbu cattle were zopkio and the great majority of these were urang. [13] They now far outnumber yak."

[IStevens, Stanley F. Claiming the High Ground: Sherpas, Subsistence, and Environmental Change in the Highest Himalaya. Berkeley: University of California Press, c1993 1993. http://ark.cdlib.org/ark:/13030/ft8b69p1t6/]

These animals are often used for carrying heavy loads in the Himalaya at moderate elevations. Yaks are more suited to the higher altitudes, and the zopkio perform better between 2500 and 3500m.

References