Screening Of Cross Combination In Cattle And Polymorphism Of Leptin Receptor Gene In Yak

Screening of cross combination is the important link for utilization of heterosis. This paper depands on Qinchuan and early wins good beef cattle′recourse in the area of east in order to screen beef crosses for production condition in local areas and provide technical support for the productive application. Feeding experiments were carried out in 26 beef cattles(♂) at 10 month divided into 5 groups including liza group (Limousin♂×Qinchuan♀F1), Xiza group (Simmental♂×Qinchuan♀F1), Nanza group (Nandewen♂×Qinchuan♀F1), Qinchuan♂F1 and Qinza(Qinchuan♂×Loculcattle♀F1), and 26 beef cattle at 24 month were slaughted, then growth and slaughter performance were analysis and comparison. The results indicated that daily body weight gain of Liza, Xiza, Nanza, Qinchuan and Qinza was 0.88,0.91,0.77,0.73 and 0.87㎏ respectively, which of Xiza was the hightest and Qinchuan was the lowest, but no difference in 5 groups(P﹥0.05). Body height and length and leg hip of Liza cattle at 24 month were significant higher than Xiza and Qinchuan respectively and heart girth of Nanza cattle was lower than Qinza significantly(P﹤0.05), but circumference of cannon bone and rump length had no difference in 5 groups(P﹥0.05). Dressing percentage and neat percentage of Liza were the highest, but hot carcass weight, Eye muscle area, dressing percentage and neat percentage had no difference in different groups(P﹥0.05). Ratio of bone to meat of Qinza group was significant lower than both of Liza and Nanza group, or carcass meat yield rate of Qinchuan was significant higher than Nanza group(P﹤0.05). Liza and Xiza cattle had the better trend of growth and development comparing with other groups and they were ideal under local management conditions.