Dutch Dairy Farms Cut Emissions by 25% with Lower Protein Feed
Wageningen, Tuesday, 24 March 2026.
Wageningen University researchers demonstrate that reducing protein in dairy cow feed from 154g to 143g per kilogram significantly decreases nitrogen emissions without affecting milk production. The multi-year study of 64 cows shows urine-nitrogen excretion dropped from 185g daily to 146g daily, while methane emissions fell from 488g to 484g per day. This breakthrough offers Dutch farmers a practical solution to meet environmental regulations amid ongoing nitrogen crisis debates.
Research Methodology Reveals Significant Impact
The comprehensive study conducted by Wageningen University & Research involved 64 dairy cows monitored over two 44-week lactation periods [1]. Researchers tested three distinct protein levels in the feed: 133, 143, and 154 grams of raw protein (RE) per kilogram of dry matter (DS), representing low, medium, and high protein diets respectively [1]. This methodology allowed scientists to establish clear correlations between dietary protein content and environmental emissions while maintaining rigorous scientific standards.
Nitrogen Reduction Delivers Environmental Benefits
The results demonstrate substantial environmental improvements when protein levels are optimized. During the first lactation period, cows fed the low protein diet (133g RE/kg DS) consumed 462g of nitrogen daily, compared to 548g and 590g for medium and high protein groups respectively [1]. More significantly, urine-nitrogen excretion decreased dramatically across the protein spectrum, with the low protein group producing only 105g daily compared to 146g for medium protein and 185g for high protein diets [1]. This represents a reduction of 43.243 percent in nitrogen excretion when comparing high to low protein feeds.
Production Efficiency Remains Viable
The research reveals that reducing protein from 154g to 143g per kilogram of dry matter does not significantly impact milk production or feed intake, providing farmers with a practical emission reduction strategy without compromising productivity [1]. However, further reduction to 133g RE/kg DS does result in decreased feed intake and milk production [1]. The current Dutch practice average stands at 161g RE/kg DS according to CBS data from 2024 [1], indicating substantial room for improvement within economically viable parameters.
Methane Emissions Show Parallel Improvements
Beyond nitrogen benefits, the study documented methane emission reductions accompanying lower protein diets. Total methane excretion decreased in the low protein group to 442g daily, compared to 484g and 488g daily for medium and high protein groups respectively during the first lactation [1]. Importantly, methane production per unit of milk or feed remained comparable across different protein levels because the low protein group experienced reduced milk yield and feed intake [1]. The research concludes that reducing protein content in dairy cow feed leads to clear decreases in nitrogen excretion, particularly through urine, without increasing methane emissions per kilogram of milk produced [1].
Timing Aligns with Dutch Nitrogen Crisis Solutions
This research arrives at a crucial moment for Dutch agriculture, as the sector faces mounting pressure to reduce nitrogen emissions under current environmental regulations. The Netherlands has established ambitious targets, including a national environmental goal for 2035 to achieve 74% less area of Natura 2000 regions with nitrogen deposition above critical deposition values [2]. Agricultural companies must demonstrate at least a 50% emission reduction compared to 2019 levels [2], making this protein reduction strategy particularly relevant for compliance efforts. The study, funded by the Netherlands Feed Research Association (VDN), LVVN, and the Dairy Cattle Fund [1], provides evidence-based solutions as the country transitions from deposition policy to emission-based target control systems [2].