Genetic Parameters and QTL Mapping for Novel Metabolic Traits in Early-Lactation Holsteins

Lay Summary In early lactation dairy cows experience increased energy demands, decreased feed intake, and compromised immune function often leading to metabolic and inflammatory diseases. The health status of dairy cows can be evaluated using blood variables that are increasingly used as indicators of metabolic and inflammatory diseases. This study investigated the genetic architecture of 12 specific blood variables in lactating Holsteins. The heritability of blood variables ranged from low to moderate and strong genetic correlations were observed between some of them. Of the 12 variables explored, cholesterol and gamma-glutamyltransferase showed moderate heritability, and the genetic variants that influence their serum levels were identified. The genomic regions that harbor these genetic variants have functions related to metabolic diseases, production, and fertility of lactating dairy cows. These insights highlight the potential utility of blood variables to improve the resilience of dairy cows through genomic tools.