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Our calf beef long-term dependence on imports, higher quality and economic value of the calf beef, the price of 3 to 6 times the adult beef. The study for the test meat samples selected from the group consisting of Datong County of Qinghai yak main producing areas, randomly selected normal development, healthy and disease-free, using stocking combination, semi-grazing, semi-rearing methods feeding Yak 6 in 6 months of age, as well as 2 to 3 years old yaks three controls. Centralized slaughtering take thoracolumbar junction fresh longissimus muscle 2kg per head, weighing and take longissimus muscle after slaughter and other parts, and then using the amino acid analyzer, flame atomic absorption spectrophotometer, dual channel atomic fluorescence spectrophotometer meter, liquid chromatography, gas chromatography - mass spectrometry and other advanced instrumentation and analytical methods, the the Yak meat nutritional quality of meat quality, fatty acids, volatile flavor compounds, heavy metals and drug residues and other aspects of a comprehensive, systematic determination. Through analysis and research, the results showed that: 1. Nutrition indicators: Yak meat moisture, crude protein content were 76.07% 22.11g/100g significantly higher than the yaks (P lt; 0.05), crude fat, ash 0.85 g/100g, 0.95g/100g, significantly lower than the yaks (P lt; 0.05); vitamin B1 content was significantly higher than the adult yak, vitamin B2 content very significantly higher than yaks; calcium, selenium content were 187.07mg/100g , 1.85mg/100g, more adult yak higher by 17.09% and 15.68% (P lt; 0.05), iron, zinc content of 294.13mg/100g 242.5mg/100g more adult yaks low 75.5mg/100g, 43.73mg / 100g (P lt; 0.05); the Yak meat samples total amino acids (TAA) 76.03g/100g, and the adult yak meat low 1.63g/100g; Yak meat essential amino acids (EAA) content of 32.85g / 100g, lower than adult yak meat, 1.14 g/100g. 2. Meat quality indicators: Yak meat flesh-colored marbling score were the 3.17,3.00 significant below adult yak (P lt; 0.05); pH24 to 5.52, the difference was not statistically significant (P gt; 0.05) ; muscle fiber diameter, shear force 23.62μm, 3.46 Kg/cm2, significantly lower than yaks (P lt; 0.01). 3 fatty acids: Yak meat, saturated fatty acids (SFA), the relative content of 53.54%, accounting for more than half of the total fatty acids, significantly lower than the adult yak (P lt; 0.01); monounsaturated fatty acids (MUFA), more than not saturated fatty acids (PUFA) were 32.38%, 11.59%, significantly higher than yaks (P LT; 0.01); polyunsaturated fatty acids and saturated fatty acids, the ratio (P: S) and n-6: n-3 values ??were were 0.22,0.98 highly significant (P lt; 0.01) and P: S yaks 2 times higher than yaks. 4. Volatile flavor compounds: Yak meat volatile flavor compounds 114 compounds, of which, 31 kinds of hydrocarbons, aromatic nine kinds of alcohol 20 to aldehyde 22 kinds, the ketone 12 kinds, six kinds of acid, ester 6 of heterocyclic five kinds, the other three species. Less compared with the adult yak 9 species, wherein at least one kind of hydrocarbons, alcohols least 6, at least two kinds of acid, at least three kinds of esters, aromatic aldehydes, ketones both have the same number, at least three kinds of heterocyclic. Play a major role on the flavor substances Yak meat 14, and in which there are nine kinds of volatile flavor compounds in the relative content of more than 1%, to acetaldehyde (8.306%) (fruity, ether incense), 3 - A thio propanal (1.848%) (onion and garlic fragrant, meaty), 3 - methylbutanal (0.036%) (dry cheese scent), benzaldehyde (2.913%) (fruity, almond flavor), heptanoic aldehyde (3.848%) (fragrance fat incense, oil incense), (E, E) -2,4 - decadienal (1.643%) (fat incense, fat incense), 2 - pentanone (0.027%) (fruit incense), 1 - octene -3 - alcohol (0.404%) (meaty, fragrance), Citronellol (3.294% (), fruity), benzothiazole (6.267%) (pyridine fragrant smell of iron), 2 - methyl furan (0.265%) (nutty), 2 - pentyl furan (2.265%) (fruity, soil, incense), 2,5 - dihydrothieno (0.347%) (grilled incense), dimethyl disulfide (2.569%) (milk flavor). Processing indicators: the Department hydraulic Yak meat, cooked meat rate were 69.43%, 66.84%, significantly higher than adult yak (P lt; 0.05), water loss rate of 20.57%, significantly lower than yaks (P lt; 0.05). Health and safety indicators: the detection of lead and mercury Yak meat is much lower than the \also not detected. In summary, the high nutritional value of calf beef, low fat, high protein, amino acid pattern FAO essential amino acid pattern close to the amino acid score, rich in vitamins; smaller muscle fiber texture, tender meat taste better than adult yak; polyunsaturated fatty acids were higher, the better quality of muscle fat; unique flavor; muscle water retention, excellent processing performance; heavy metal content is not excessive, veterinary drug residues, and a high level of consumption and the development value, natural pollution \
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