Allele Frequency of 1 Mutation in Holstein Cattle in Brazil.

1 is an autosomal recessive inherited mutation, associated with Holstein haplotype 1 (HH1) and characterized by a substitution of cytosine for a thymine (c.1741C>T) in chromosome 5. The mutation causes fetal and embryonic loss, between 60 and 200 days of gestation, and reduced conception rate. The -PCR is considered a simple and low-cost method to determine single nucleotide polymorphism (SNP) with no need for genetic sequencing of the animal genome. This study aimed to verify the allelic frequency of 1 mutation in Brazilian Holstein cattle. A total of 248 Holstein DNA samples (210 cows and 38 bulls) were analyzed, and synthetic genes were manufactured to validate the primers developed by the authors. All animals assessed in this study were classified as wild-type for 1 mutation. The primers and protocol developed for the -PCR technique work with 100% specificity and efficiency since the amplicon formations are as expected according to the genotypes. In conclusion, the mutation responsible for 1 was not detected in the Brazilian Holstein cattle population assessed in this prevalence study, although it is not possible to affirm that 1 does not occur in Brazilian Holstein animals. The tetra-primer -PCR protocol for 1 mutation that has been validated here may be a relatively simple and economical method to determine the animals' genotype.