New polymorphism in the bovine STAT5A gene and its association with meat production traits in beef cattle*

STAT5 is a group of transcription factors that mediate signals from prolactin and growth hormone. Therefore, STAT5A gene is a candidate marker for quantitative traits in farm animals. In this study the new nucleotide sequence polymorphism was found in the coding region of the bovine STAT5A gene substitution C→T at position 6853 within the exon 7. As this mutation creates new AvaI/DdeI restriction site it could be easily detected with PCR-RFLP analysis. The RFLP-AvaI polymorphism was studied in cattle (n = 146) belonging to eight breeds, including two considered as Polish native. The overall frequencies of alleles C and T were 0.82 and 0.18, respectively. The genotype TT was found exclusively in both native breeds (Polish Red and White-Back). Moreover, for the first time an association was reported between STAT5A gene polymorphism and beef production traits in cattle (n = 71). In the animals of the CC genotype the live body weight at the age of 9 and 15 months, live weight gain (0-15 months), dressing percentage and four carcass traits were found more favourable than in CT animals. Individuals CC used less feed for maintenance and meat production.