ESTUDIO DEL POLIMORFISMO HINFI DEL GEN PIT-1 Y SU ASOCIACIóN CON CARACTERíSTICAS DE TIPO, PRODUCCIóN DE LECHE Y DíAS ABIERTOS DE VACAS HOLSTEIN EN EL DEPARTAMENTO DE ANTIOQUIA, COLOMBIA

the aim of this study was to determine allele and phenotypic frequencies for single nucleotide polymorphism (snp) of exon vi in the pit-1 gene and their associations with type traits, milk yield, and days open. a total of 390 holstein cows from antioquia (colombia) were genotyped for the pit-1 hinfi polymorphism by pcr-rflp. we found aa, ab, and bb genotypes with a frequency of 0.03, 0.43, and 0.53, respectively. the a allele frequency was 0.35 and its presence in the genotype was associated with higher milk production, udder depth and body depth; the absence of the a allele in the genotype was associated with fewer days open. this study indicates that it is possible to develop breeding programs using the pit-1 gene in holstein cattle in the department of antioquia.