Proteins found in cow's milk are one of the main sources of childhood allergies and can affect up to 7% of children. A more common allergen is beta-lactoglobulin (BGL), which makes up more than 50% of whey protein and is absent in human milk. Hypoallergenic cow's milk can be obtained by treating the milk, but this can result in residual antigenicity and alter the taste of the milk. Additionally, prices are 10-15x higher than conventional milk. The bovine BGL gene is located on chromosome 11 and its expression can be silenced by genome editing. In this project to edit the BGL gene, we used the CRISPR-Cas9 system to promote mutation in bovine cells and embryos with the aim of generating knockout animals for this gene in the future. We evaluated different sgRNA guides in bovine cells and verified their efficiency in promoting DNA strand cleavage, which through non-homologous strand repair (NHEJ) can promote insertions/deletions (indels) and prevent the adequate expression of the gene. To evaluate such guides in bovine cells, we produced a population of cells with constitutive expression of the Cas9 endonuclease, so that we could evaluate sgRNA more efficiently, since transfections with sgRNA and CAs9 mRNA in fibroblasts showed low efficiency. Subsequently, the guides were evaluated in microinjected bovine embryos and it was verified a lesser efficiency than expected. New sgRNA were designed, synthesized and used in bovine embryos. One of them resulted in an indel promotion efficiency of 36% and was used for microinjection of embryos for transferring to recipients. Microinjected embryos resulted in a pregnancy rate of 38.4%. An animal derived from an embryo injected with the CRISPR/Cas9 system was produced aiming to mutate the beta-lactoglobulin gene. Despite presenting chimerism, it showed that it is feasible to generate animals from embryos injected with this gene editing system in our conditions, so that studies involving the editing of this gene must be stimulated, with the aim of obtaining animals that produce hypoallergenic milk due to the absence of this protein.