Three short tandem repeats (STRs), BMS1074, BM1500, IDVGA-51, and three single nucleotide polymorphisms (SNPs), LEPSau3AI (A/B), LEPSau3AI (+/-) and LEPKpn2I linked to the LEP gene were investigated to verify associations with productive performance in postpartum cows of two beef cattle breeds, Aberdeen Angus (AA, n=98) and Charolais (C, n=83). After polymerase chain reaction, STRs were analyzed by vertical electrophoresis and SNPs in agarose gel after endonucleases cleavage. In AA herd 79% of BMS1074*151 carriers had a lower average daily weight gain (ADG) when compared with the population mean daily weight gain (103g), while 62% of BMS1074*151 non-carriers presented a higher ADG (P<0.01); AA animals with at least one BMS1074*151 allele showed a ADG about 159g lower than that of other animals (P<0.01). In both herds, carriers of the BM1500*136 allele presented higher ADG (about 75g day-1 higher in AA, P<0.05, and 96g day-1 in C, P<0.10); animals with one BM1500*136 allele had about a 3-fold higher chance of having a higher ADG than non-cariers, in both populations.
Leptin; STRs; SNPs; beef cattle; weight gain; post-partum
