Review: Genomic blueprint of cow longevity

Improving dairy cattle performance in a sustainable way should imply developing breeding programmes able to enhance both productive and functional traits without increasing the environmental footprint. Although several studies investigated cow longevity, a fully integrated international framework that coherently links biological understanding, genomic and genetic evaluation systems, and management strategies is needed. This review addresses this issue by examining peer-reviewed articles focusing on trait biology, phenotyping, genetic and genomic evaluations, or management strategies influencing longevity. Intensive selection for production traits has historically reduced cow resilience and longevity. In the U.S., genomic evaluations for livability were introduced in 2016 and included in the Net Merit index in 2017, while productive life (incorporated in the index since 1994) has shown notable genetic gains, particularly since the adoption of genomic selection. Genotyping has markedly increased the accuracy of identifying sires whose daughters remain longer in the herd, despite the low heritability of longevity traits. Nevertheless, the average productive life may be around 3-4 years, and management decisions continue to shorten cows' productive life, with many culling occurring without evident health or reproductive issues. Extending productive life would provide a better welfare for the animals and a reduced environmental footprint.