Potential mechanism of the effect of heat stress on milk protein synthesis revealed by integrated metabolomic and proteomic analyses

Summary

This experimental study examined how varying degrees of heat stress (no, mild, and moderate) affect milk protein synthesis in dairy cows using integrated metabolomic and proteomic analyses. The research demonstrated that moderate heat stress significantly impairs amino acid supply and uptake in the mammary gland whilst downregulating key proteins required for protein synthesis and folding, ultimately reducing milk protein yield. The findings suggest that heat stress disrupts metabolic efficiency in dairy production and identify potential intervention points to mitigate production losses under thermal stress.

Regional applicability

The findings are relevant to UK dairy farming as climate change increases the frequency and intensity of heat stress events, particularly during summer months. Understanding these mechanistic pathways could inform on-farm management strategies and nutritional interventions to protect milk yield and composition during heat stress episodes.

Key measures

Milk protein yield, arterial and venous blood amino acid concentration, mammary gland amino acid supply and uptake, milk metabolomic profiles (nucleotide and energy metabolism), milk proteomic profiles (ribosomal and heat shock proteins)

Outcomes reported

The study measured milk protein yield, amino acid concentration and uptake in arterial and venous blood, and conducted metabolomic and proteomic analyses of milk samples across three heat stress conditions. Key findings included significantly reduced milk protein yield under mild and moderate heat stress, with corresponding disruptions in amino acid utilisation and downregulation of ribosomal and heat shock proteins.

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