Abstract: The aim of this study was to analyze the association of Pit-1 gene polymorphisms with fattening and growth traits in Simmental. In this study, the locus of Hinf Ⅰ of Pit-1 gene was genotyped by PCR-RFLP in Simmental to investigate the associations. The results showed that the locus of Hinf Ⅰ was significantly associated with feed conversion rate and average daily gain traits(P＜0.05).The phenotype of the BB genotype were significantly better with a lower FCR and a higher ADG value. The locus of Hinf Ⅰ had an major affect on height at withers at 8 and 15 months of age, body length at 12 and 15 months of age, chest girth at 8, 12 and 15 months of age and girth of paunch at 8 months of age.Among the phenotypes which were significantly associated, individuals with homozygote of BB genotype had a significantly higher average value than that of AA genotype(P＜0.05). As for the carcass length, carcass chest depth and loin meat thickness traits, individuals with homozygote of BB genotype also had a significantly higher average value than that of AA and AB genotypes(P＜0.05). So the BB genotype was significantly associated with the fine fattening performance and the selection of the allele B was better for the trait improvement.

Key words: Pit-1; growth trait; fattening traits; association analysis