Polymorphisms of leptin, β-lactoglobulin and pituitary transcription factor have no effect on milk characteristics in crossbred cows

Milk production systems installed in the Brazilian semiarid region are used on a large scale, in which the European breeds specialized in milk production are hybridized with zebu breeds more suited to a climate with semiarid conditions (Façanha et al., 2017). The result of this crossbreeding produces animals that are less productive, although better adapted to the tropics, which has increased the productivity and viability of dairy farming in the semiarid northeast. Allelic identification of the different genotypes of dairy cows, using molecular biology techniques, is used to make adjustments in genetic improvement programs, directing crosses of different genetic groups for more efficient gains in animal production systems. 