| The experiment material was 60 Gannan female yaks.20 of them were the treatment group one, 20 were the treatment group two, the other 20 Gannan yaks were the control group. These two treatment group female yaks were employed with artificial insemination during their oestrous cycle, the frozen–thawed bovine semen was came from Simmental Bull. The control group was managed traditional systems and mated with male yaks in voluntary grazing conditions. All female yaks'conception rate were determined after their fertilization and all their calves weight, body length, height at withers and heart girth were determined every month before and after grazed from birth . The result showed the following:1,conception rate:The treatment group one's conception rate came to 66.79 %,it was higher 18.58 % than the control's, and the treatment group two's conception rate came to ,and it was higher19.13 % than the control's, while the control's is just 48.21%.2,The difference of growth index:The result showed that all groups weight were in same level at their birth day ,there is no significance between them(p>0.05).The two treatments calves grew faster before 6-month.The weight of treatment group one was 92.94±1.29 kg per head at their 6-month, and the weight of treatment group two was 78.08±1.31 kg per head. Then they grew slowly until they were in 10-month, after that they grew faster than before, then they were in down until 14-month. When they were in 18-month, the weight of treatment group one was162.60±2.07 kg per head, and the weight of treatment group one was151.34±1.10 kg per head at their 18-month , there is no significance between them(p>0.05).While the control group had different growing speed from the treatment one, the control calves grew faster than the treatment groups, their weight were up to the first summit, the weight of treatment group one was 112.93±6.37 kg per head at their 10-month, then they grew slower than before, after 15 months their growth speed became faster, the difference between these two groups and control group was significant from the beginning to end(p<0.05).3,The contrast between the rule index:This experiment indicated that the body oblique length of treatment group one was 54.23±2.13 cm at new birth and 130.42±2.54 cm at their 18-month, the body oblique length of treatment group one was 52.16±1.62 cm at new birth and 124.35±2.63cm at their 18-month, there is no significance between them(p>0.05);While the body oblique length of control group was 48.11±1.16 cm at new birth and 109.50±2.18 cm at their 18-month, there is significance between treatment group and control group (p<0.05).The heart girth of treatment group one was 60.34±2.76 cm at new birth and 135.47±2.37cm at their 18-month, the heart girth of treatment group two was 58.67±3.15 cm at new birth and 131.49±2.66 cm at their 18-month, there is no significance between them(p>0.05); While the heart girth of control group was 0.78±2.05 cm at new birth and 131.18±2.10 cm, there is significance between treatment group and control group from the beginning to end (p<0.05).The treatment group one height at withers was 59.11±2.12 cm at new birth and 134.29±2.86 cm at their 18-month, the treatment group two height at withers was 57.17±2.18 cm at new birth and 131.71±2.44 cm at their 18-month, there is significance between treatment group and control group from the beginning to end (p<0.05).The three calves circumference of cannon bone mainly focus on the former period, and there was no significance in circumference of cannon bone between them from the beginning to end (p﹥0.05).In general , the experiment showed that at Azi experiment station of Gansu Ganna , the best breed is number 52 Simmental Bull's frozen semen after determined their conception rate and the index of growth. |
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