The number of yaks in China takes up 85% of the world's total yak population and one sixth of the total number of cattle in China. It is an indispensable cattle breed in China. Yaks are also the major source of milk and meat, and it is a main transportation means on the highland where minority groups live. Milk production of Chinese yaks is 68% of the total milk production of Holstein-Friesians in China. The milk fat percentage of Chinese yaks is more than that of Holstein-Friesians. The milk production of improved yaks through AI of frozen semen of Holstein-Friesians could increase by 100-300%. Therefore, milk purpose is the first priority of the three purposes of yaks. Six suggestions are brought forward in the paper as follows:

1. On the highland pastoral zone, milk, meat and draft purposes should be applied in yak development, and the first priority should be given to milk purpose;
2. further improve AI technique of frozen semen and reproductive and survival rate of yaks;
3. China Dairy Association and China Coordinating Team of Scientific Research on Yaks should strengthen contact with each other, trying to obtain mutual promotion and development;
4. constructive investment and grants should be given to yak development on a certain percentage;
5. milking, processing, marketing and raising of yaks should be well done in time;
6. reasonable benefit should be given to related personnel.

Key Words: Yak, Three Purposes, Dairy Purpose

[Source: China Yak, first issue, 1983]

On Kangwu and Yaqu Farm, over 300 yak calves suffered from bacillary white diarrhea and blood dung (BWD) in 1980. The dung and rectal mucosa of sick yaks were examined with microscope to find a kind of coccidium similar to Avian Coccidium. Several medicines were applied to the sick animals for treatment. The best was SMP and SD, with a healing rate of 100%. The healing rate of dipterex is 80%, and that of Artemisia apiacea prescription is 71.3%. Penicillin and streptomycin can reduce the symptom, but they cannot heal the disease. The dipterex tablets are effective, but have some bad influence on sick calves. The suggested dose is 0.035 gram per kg body weight. The daily application of dipterex for a sick animal of 20 kg is 0.75 gram, and the maximum dose should not exceed 1 gram.

Key Words: Yak, Coccidiosis, Study

[Source: China Yak, fourth issue, 1982]

In June-August 1981, the body size was measured of yaks in Hebei Township, Tongde county. The average body height of 30 adult female yaks was 102.90 cm, average body length was 116.6 cm, average chest girth was 146.2 cm, average cannon circumference was 15.1 cm, and body weight was 175.8 kg. The average body height of ten adult male yaks was 119 cm. The average body length was 173.6 cm, average cannon circumferance was 18.1 cm, and the average body weight was 288.4 kg. Among 30 adult steers the average body height was 112.1 cm, average body length was 123 cm, chest girth was 154.4 cm, cannon circumference was 17.4 cm, and body weight was 210.3 kg.

Key Words: Yak, Body Length, Determination

[Source: China Yak, fourth issue, 1982]

There were 79,941 yaks at the end of 1980 in Tongren County, Qinghai Province. Twenty-seven adult steers were selected for a body size and weight test. The average body height was 117.7 cm, average body weight was 269.89 kg, body length was 124.64 cm, chest girth was 175.6 cm, and cannon circumference was 21.1 cm. The average daily milk production from June through October was 1.11-4.9 kg. Four adult female yaks were tested, and among them the average live weight was 166.9 kg, carcass weight was 70.5 kg, and the average dressing percentage was 42.3%. The yak could carry a burden as heavy as 100 kg, walking 30-40 km a day for a constant three to five days. Every yak steer in Duowa Township produced 0.165 kg down per year, with wool production of 0.875 kg. The male yaks for mating purposes produced 0.26 kg, with wool production of 1.3 kgs. Tongren female yaks could calve for nine litters. Seventy-five percent of Tongren yaks calved for two litters within three years, and 14% calved for one litter within two years. Around 11% of Tongren yaks calved for one litter per year.

Key Words: Tongren County, Current Yak Production, Survey

[Source: China Yak, fourth issue, 1982]

Yele is located in the northeast of Mianning county where Shimian and Jiulong county join with each other. The lowest point in Yele is 2,538 meter above sea level, and the highest point is 4,939 meters above sea level. The total area of Yele is 359.4 square kilometers, equal to 539,100 mu, among which 207,472 mu is grassland (38.4% of the total). In the survey, 275 pasture samples were collected, to find that the major fodder plants were of 131 species in 101 genus in 46 families. One way people are better off in Yele is by making full use of the forest and grassland resources to develop foresting and livestock production. Livestock production should be combined with foresting on the basis of protection and reasonable utilization of the current natural grassland of over 200,000 mu. Rearing and planting of pasture species that prove to be highly productive should be strengthened. Artificial grassland should be built up to ensure a steady and balanced grass supply for livestock.

Key Words: Yele Grassland, Resource Survey, Report

[Source: China Yak, fourth issue, 1982]

There are large areas of ranches in the Altai mountains where it is difficult for sheep, goats and cattle to go. However, yaks and their crossbreeds could make full use of these ranches. The life length of yaks is usually seven years. The body weight of a female yak is 270-280 kg, and a male yak weighs 350-450 kg. In March-April, each female yak produced 300-400 kg of milk with a fat percentage of six to seven percent. The body weight of a crossbred yak is 25-30% more than that of yaks and cattle, with improved beef quality. The dressing percentage of fattened crossbred yaks is 58-60%. In order to obtain the best hybridized combination of yaks, three experiments were conducted in A Jia Qi Si region in 1959. The initial weight of calves born through inter-mating was 15.4 kg for the female and 15.6 kg for the male. The initial weight of female and male calves of male yak x Simmental was 20.8 kg and 20.4 kg.

The initial weight female and male calves of female yak x male dwarf cattle was 21.1 and 25.8 kg. When fattened to 20 days, the live weight increased to 277.5 kg, and it was 262.3 kg for Simmental x Yak crossbred, and 139.2 kg for Simmental x yak. Slaughtered after fattening, the carcass weight of the crossbreed of yak x dwarf cattle was twice as much as that of yak. For the Simmental x yak cross, the carcass weight was 1.67 times as much as that of yak. Slaughter weight of the yak x dwarf cattle cross was 30.4 kg more than that of Simmental x yak cross, and 84.7 kg more than a yak. In terms of the weight of edible parts of the carcass body, the crossbreed of yak x dwarf cattle cross was better than Simmental x yak cross.

Key Words: Altai Mountains, Yak, Crossbred

[Source: China Yak, fourth issue, 1982]

The Editorial Committee of China Yak held its third plenary session in Chengdu on 12 September 1982. At the plenary session, a summary of the past year and recognition of achievements were made, and existing problems and suggestions for improvement were brought forward. Dr. Chen Shaojiong, deputy director of China Academy of Agriculture Science, made some practical suggestions. He thought that China Yak should enlarge its range of soliciting contributions. All academic essays, experience exchange articles, literature reporting advanced individuals, and other reporting articles on special subjects should be published in China Yak regarding grassland, animal husbandry & veterinary medicine, industry, agriculture, commerce, and foreign trade. A special column for grassroots livestock workers should be opened to publish some small articles such as tips for livestock production and lectures on application science.

More was discussed at the plenary session, including further consolidation of contact with editors working outside Sichuan province. There was also discussion of a network of China Yak communicators, and reports on labor models and advanced individuals. All these reports should have the seals of related units.

Key Words: China Yak, Editorial Committee, Plenary

[Source: China Yak, fourth issue, 1982]

A survey was conducted on milk performance, milk quality and the correlation coefficients between them in Batang District, Wangshu Prefecture in 1980. Of the 97 yaks, each one produced 97.5 kg of milk per month. The highest production was in July, and was followed by a dramatic drop in August and September before stablizing in October. In terms of litters, the milk yield is the highest for a yak that has calved for five litters, producing around ten kg per yak per month.

The milk production tends to go up from the first calving through the fifth, and it begins to go down at the sixth calving. The density of yak milk is 36.58 degrees on average, more than that of ordinary dairy cows. The milk density is smallest for a yak that only calved once, and it is biggest for a yak that has calved for five times. In August, September, and October, the average milk fat percentage was 6.37%, the highest being in October, and the lowest in August and September. In terms of litters, it is the highest for yaks that calved for two and six times, and lowest for yaks that calved for three times. The milk fat percentage of yaks is 22-85% higher than dairy cattle and dual-purpose cattle.

The factors that influence milk yield of yaks are: Milk yield of yaks is influenced by weather conditions, with the highest yield on rainy days, followed by cloudy days and lastly sunny days. Milk rate and production is higher in the daylight than at night. Significant positive correlation existed between milk yield of yaks and the value of distance between intercostal angles, length of the switch of the tail, chest hair length, paunch girth, nostril departure, thurl width, intercostal distance, chest girth and cannon circumference. Weak positive correlation existed between milk yield and the value of head width, intercostal width, skin thickness, and paunch hair length.

Key Words: Yak, Milk Performance, Milk Quality, Correlation Coefficient

[Source: China Yak, first issue, 1983]

A test of in vivo insemination of frozen semen was conducted on yaks on Baihe Farm, Sichuan province in 1981-82. Of 52 yaks inseminated with frozen semen that had not been defrosted, 25 became pregnant (conception rate - 48.07%). Of 61 yaks inseminated with defrosted frozen semen, 24 became pregnant (conception rate - 39.34%). The insemination technique (direct insemination of frozen semen without being defrosted) proved to have a conception rate of 8.73% more than the second technique of defrosting before insemination. It is convenient and feasible to defrost frozen semen through body heat inside the uterine of female yaks. This is good for minimizing contamination, keeping sperm vitality, improving conception rate, reducing cost, saving labor, and minimizing open rate of female yaks.

Key Words: Interspecific Hybridization, Frozen Semen, In Vivo Defrosting, Conception Rate

[Source: China Yak, first issue, 1983]

In artificial insemination on the Waqie Farm, Anqu Township, Hongyuan county, the following results were obtained. 1) Female yaks to be mated must be well selected. Generally semi-whole cattle should be selected, and dry milk cattle is the next priority. 2) Improve the insemination technique. The AI conductor must identify a female cattle in estrus and apply artificial insemination in time. 3) Not only should the conception rate of the first estrus period be strengthened, but also the repeat mating of the second and third estrus period. 4) Quarantine and control of yak brucellosis should be strengthened. The conception rate of yaks infected with brucellosis dropped 21.87% as compared with the average level, with abortion and death rate of 4.24%. 5) Take good care of calves and female yaks.

Key Words: Yak, Interspecific Hybridization, Reproductive and Survival Rate

[Source: China Yak, first issue, 1983]