Hepatic Transcriptome Reveals Potential Key Genes Contributing to Differential Milk Production

Area of Science:

• Genomics and Animal Science
• Molecular Biology
• Dairy Cattle Metabolism

Background:

• Individual dairy cow milk production varies despite standardized feeding protocols.
• The liver is a crucial organ for regulating lactation metabolism and initiating milk production.

Purpose of the Study:

• To identify key genes in the liver associated with variations in dairy cow milk production.
• To explore the genetic underpinnings of high versus low milk yield in dairy cattle.

Main Methods:

• RNA sequencing (RNAseq) was performed on liver samples from high and low milk yield (MY) dairy cows.
• Weighted gene co-expression network analysis (WGCNA) and machine learning models were employed to identify significant genes.

Main Results:

• 795 differentially expressed genes (DGEs) were identified, with up-regulation linked to morphogenesis and development.
• Eight hub genes (six positive, two negative) were significantly associated with milk yield, and a model using these genes predicted MY with high accuracy (R² = 0.946).
• Gene expression patterns remained consistent pre- and postpartum.

Conclusions:

• The liver plays a critical role in milk production, with morphogenesis and development pathways influencing yield.
• Identified hub genes provide valuable genetic markers for selective breeding in dairy cows to enhance milk production.