Research On Fattening And Slaughter Performance And Molecular Marker Analysis In Guyuan Local Cattle And Crossbreed Of Limousin×Local Cattle

In order to analyze the crossing improvement of Limousin cattle to Guyuan Local cattle, and screen the molecular markers relative with the fattening and slaughter performance, the fattening and slaughter performance of Guyuan Local cattle and crossbreed of Limousin×Local cattle had been determined. PCR-RFLP, PCR-SSCP and sequencing techniques had been used to analyze the molecular characteristic of Pit-1 gene, H-FABP gene and TG gene in Guyuan Local cattle and crossbreed of Limosin×Local cattle, and then the association with production performance had been analyzed, the results show that:1 The crossbreed of Limousin×Local cattle in the 6 month group had better average daily gain and concentrate feed intake than the Local cattle (P<0.05). Crossbreeding affected the body weight and body size of the Local cattle significantly, the body weight, body height, height at hip cross, heart girth, circumference of cannon bone and hipbone width of the crossbreed of Limousin×Local cattle were higher than the Local cattle at the same age significantly at the level of P<0.01 or P<0.05, respectively. The weight gain in the fattening of the crossbreed of Limousin×Local cattle were greater than the Local cattle, and the 18 month group greater than 6 month group, respectively. The crossbreed of Limousin×Local cattle in the 18 month group had higher concentrate feed intake of 140 days (P<0.05), higher average daily gain and concentrate to gain ratio (P>0.05) than the Local cattle. The age had positive effects to the average daily gain, concentrate feed intake, body size and body weight, and negative effects to the efficiency.2 The body fatness index, head weight, tail weight, hoof weight, carcass weight, bone weight and net meat weight of the crossbreed of Limousin×Local cattle were higher than the Local cattle significantly at the level of P<0.05 or P<0.01. The dressing percentage, meat percentage, carcass meat percentage and meat to bone ratio of the crossbreed of Limousin×Local cattle were higher than the Local cattle in the 24 month groups significantly at the level of P<0.05 or P<0.01, which had improved 4%, 4%, 3% and 0.72, respectively, but there were no difference in the 12 month groups (P>0.05). The eye muscle area, marbling, muscle color and muscle insertion of the corssbreed of Limousin×Local cattle were better than the Local cattle (P<0.05). The difference of the conventional ingredient content and the fatty acids distribution between the crossbreed of Limousin×Local cattle and Guyuan Local cattle was no significant (P>0.05). But there were some trends that the crossbreed of Limousin×Local cattle had higher crude protein content and lower crude fat content, oleic acid, linoleic acid and all unsaturated fatty acid content. The age had positive effects to the dressing percentage, meat percentage, carcass meat percentage, meat to bone ratio, eye muscle area, crude fat, and negative effects to the shearing force, dehydrating rate, and water content.3 PCR-RFLP was applied to analyze the polymorphisms of Pit-1 gene in Guyuan Local cattle and crossbreed of Limosin×Local cattle, and then the association with fattening traits had been analyzed. The results showed that 451 bp PCR products digested with HinfⅠdemonstrated polymorphisms in Guyuan Local cattle and crossbreed of Limosin×Local cattle which were all at Hardy-Weinberg equilibrium, the frequencies of allele A/B were 0.3039/0.6961 and 0.1614/0.8386, respectively. The association between the polymorphisms of Pit-1 gene and some fattening traits show that: the individuals of genotype BB and AB had lower concentrates to gain ratio in the first stage of the fattening (P<0.05), and BB