Can nutritional grouping lower feed costs and enteric methane when diets are optimized with modest ingredient...

Area of Science:

• Agricultural Science
• Animal Science
• Environmental Science

Background:

• Nutritional grouping (NG) precisely delivers nutrients to dairy cows, enhancing economic returns.
• Enteric methane emissions from cows are a significant greenhouse gas source, influenced by diet.
• Concerns about climate change necessitate evaluating NG's potential for methane reduction.

Purpose of the Study:

• To assess the impact of nutritional grouping (NG) on feed costs and enteric methane emissions.
• To develop an open-source linear optimization model for evaluating NG strategies.
• To identify optimal feeding strategies balancing economic and environmental goals in dairy farming.

Main Methods:

• Developed an open-source linear optimization model.
• Conducted a case study with 675 cows at the University of Wisconsin's Arlington Agricultural Research Station.
• Formulated diets using actual farm feed ingredients and prices, adhering to feeding guidelines.

Main Results:

• Optimization alone reduced feed costs by 32% and methane by 12% compared to the on-farm diet.
• A dual-objective approach balanced cost and methane reduction, yielding a compromise solution.
• Nutritional grouping modestly improved non-target outcomes (e.g., lower methane when minimizing cost).

Conclusions:

• Optimized rations using existing feeds provide significant economic and environmental advantages.
• Nutritional grouping offers an additional management refinement for reducing feed costs.
• NG can provide complementary benefits for methane reduction when considered alongside economic objectives.