The Effect Of Diets With Different Protein Contents On The Fattening Performance And Carcass Quality Of Sheep In Stall Feeding System

90 droset born 30 days that were health and no sickness Droset(♂)×small tail han sheep(♀)crossbred barrow lambs, Which had same age and similar weight, were divided into 3 groups with 3 replications by completely random. The experiment mainly discussed the effect of protein levels diet on growth performance of lamb in 40-90 days and 100-180 days, and analysed the effect diets with different protein contents on slaughter index and meat quality of lamb slaughtered at 180 days. The experimenat results were following: During 40-90 days of lamb, lambs were fed 17%(G2)crude protein(CP)level diets, Average daily gain of lamb was 319g/d, and weight at the end of experiment reached 26.34Kg, which were significantly higher (p<0.05) than lambs that were feed 15%(G3)CP level of TMR; However, During the period of nursing; The lambs fed 19%(G1)CP level of TMR had more optimal feed conversion efficiency than G3, but the difference is not remarkable (p>0.05);The experiment found, lamb should be early fed solid foods, And raising time didn't last too long, Weaning age was appropriate from 60 days to 70 days after lamb born. During the time of lambs weaned, weaning stress was exceedingly obvious. Lamb fed 17%(F1)CP diet grew faster than those fed 15%(F2)and 13%(F3)level of diet protein, it allowed for a smother transition on to growth; Through 80d fattening period, the weight of three experimental groups lambs reached 45.10±4.43Kg, 45.27±3.43Kg, 42.39±4.32Kg respectively, The difference was significant (P<0.05),Weight gain of F1, F2 group were higher 6.49% and 6.84% than that of F3. Additionally, through the analysis of economic benefits among groups, F2 group made more commercial profits; Physical growth of three groups were not significant difference (p>0.05), But positive correlation existed between chest circumference , chest depth and weight. The results of slaughter demonstrate, Dressing percentage and pure meat percentage of lamb fed 15% CP% diet, were 52.74%, 77.01% respectively, and main slaughter indexes were higher than that of lamb fed 17% CP and 13% CP diet; With the increasing of protein level of diets. The tendency was that high quality cutting part percentage of lamb obviously rised; Through analysis of meat quality among three groups, the significant difference was not found, but the meat of F1 group lamb, was in rich in content of crude protein and crude fat; The content of amino acid was determined, the results showed that meat of lamb fed 17% CP diet contained a great deal of necessary amino acid and fleshy amino acid, and content was remarkable higher (p<0.05) than that other groups.