During the second half of the 20th century, producers using selective breeding focused on creating livestock breeds and crossbreeds that increased production, while mostly disregarding the need to preserve genetic diversity.
dˈʊɹɹɪŋ ðə sˈɛkənd hˈæf ʌvðə twˈɛntiəθ sˈɛntʃɚɹi, pɹədˈuːsɚz jˈuːzɪŋ sᵻlˈɛktɪv bɹˈiːdɪŋ fˈoʊkəst ˌɔn kɹiːˈeɪɾɪŋ lˈaɪvstɑːk bɹˈiːdz ænd kɹˈɔsbɹiːdz ðæt ɪŋkɹˈiːst pɹədˈʌkʃən, wˌaɪl mˈoʊstli dˌɪsɹɪɡˈɑːɹdɪŋ ðə nˈiːd tə pɹɪzˈɜːv dʒɪnˈɛɾɪk daɪvˈɜːsᵻɾi.