Balchem (BCPC) Status Update summary

Introduction and context

• Protein nutrition is central to sustainable dairy production due to its impact on milk yield and environmental nitrogen losses.

• Imported feed is the largest nitrogen input, contributing to environmental issues like biodiversity loss, water pollution, and greenhouse gas emissions.

• Nitrogen pollution is a global issue, with hotspots in both Europe and the US, leading to regulatory and public trust challenges.

• Regulatory and public pressures are increasing focus on nitrogen discharge and sustainable feed practices.

• Dairy cows can repurpose inedible feed into nutrient-rich food, but managing manure nitrogen surplus remains a key concern.

Metabolic flexibility and energy source in protein nutrition

• Dairy cattle exhibit metabolic flexibility in the rumen, post-rumen digestive tract, and post-absorptive system, allowing adaptation to different feed resources.

• Protein efficiency in milk production is closely linked to the type and supply of dietary energy.

• Glucogenic energy (e.g., starch-rich feeds) increases milk protein yield and nitrogen efficiency by stimulating insulin and shifting amino acid partitioning.

• Lipogenic energy (e.g., fat supplements) can improve nitrogen efficiency at low protein levels, but its effects are less understood and do not affect amino acid partitioning.

• Flexibility enables tailored strategies for protein efficiency based on farm-specific sustainability targets and ingredient availability.

Rumen protein balance and nitrogen recycling

• Excess rumen available nitrogen leads to increased urinary nitrogen excretion, with most surplus nitrogen lost.

• Balancing for estimated rumen nitrogen requirements by adding urea may increase nitrogen excretion without improving milk yield or protein content.

• Endogenous urea recycling increases as dietary protein decreases, offering potential to reduce dietary crude protein and nitrogen excretion.

• More research is needed on urea recycling dynamics in lactating dairy cattle.

• Higher fermentable carbohydrate diets paired with lower rumen degradable protein can increase urea recycling.