Inbreeding becomes a serious issue



Analyses of SNP data of Holstein genotypes present at Anafibj has been done to verify trends in genetic variation over time. Results show a linear decline of SNP heterozygosity in the pre-genomics era from 1990-2010, and a 5-fold larger linear decline in the genomics era from 2010-2023. This is a clear signal that the increased annual genetic progress from genomic selection goes together with a strong decrease in genetic variation. Pedigree based inbreeding rates show Italy, USA and Canada having the highest annual inbreeding rates for Holsteins among countries. Strong market competition for AI centers results in the intense selection of a smaller number of elite animals. Emphasis on short-term genetic gain might be harmful for maintaining the long-term health and diversity of the breed. In Italy, research is underway to attempt to counter the harmful effects of decrease in genetic variation as well as genetic disorders.