Changes in terpene content in milk from pasture-fed cows

Area of Science:

• Animal Science
• Dairy Science
• Forage Science

Background:

• Terpenes in milk originate from grazed plants.
• Understanding terpene variations is crucial for dairy production and feed analysis.

Purpose of the Study:

• To investigate the influence of different grazing management strategies on milk terpene profiles.
• To assess the impact of pasture botanical composition and grazing methods on terpene content in dairy cow milk.

Main Methods:

• Observational trial comparing strip grazing (SG) and paddock grazing (PG) on diversified upland pasture.
• Analysis of milk terpene content using dynamic headspace gas chromatography-mass spectrometry.
• Monitoring pasture botanical composition and plant development stages.

Main Results:

• Strip grazing led to an eight-fold increase in milk terpenes during the first growth period.
• Paddock grazing resulted in lower terpene variability, potentially due to cows' selective grazing.
• Milk from cows grazing regrowth pastures in October had low terpene levels, similar for both grazing methods.
• Specific monoterpenes (e.g., beta-pinene) and sesquiterpenes (e.g., beta-caryophyllene) were most abundant.

Conclusions:

• Grazing management significantly affects milk terpene content, alongside pasture botanical composition.
• The variability in terpene content suggests that cows' dietary selection plays a key role.
• Further research is needed to understand the nuances of grazing management on milk terpenes and their reliability as feed tracers.