Global analysis of nutritional strategies to mitigate the environmental impacts of dairy production: the case of supplementing diets with microencapsulated B vitamins

Over the last decade, policymakers and dairy producers worldwide have faced the challenge of reducing the environmental impact of dairy production while continuing to meet societal needs for high-quality and nutritious protein sources. Given this, the objective of the present study was to assess the net environmental impact of adopting different nutrition strategies with and without supplementing rumen-protected B vitamins (RPBV, B vitamins that are microencapsulated to bypass rumen degradation in cows and be absorbed in the small intestines) in dairy milk production. Seven representative regional dairy production systems across the United States, Canada, Mexico, Chile, Colombia, Australia, and France were investigated, utilizing a total mixed ration (TMR) feeding program supplemented with 3 g of RPBV. The estimated climate change impact scores for all control production scenarios ranged from 1.08 to 1.65 kg CO₂-eq/kg fat protein-corrected milk (FPCM). However, the impact of climate change per kg of FPCM decreased by 5.6–18.0 % when RPBV was supplemented on top of the TMR feeding program. The highest and lowest climate change impact reductions were observed for the RPBV production scenarios in Mexico and Colombia, where the impacts decreased from 1.65 to 1.36 kg CO₂-eq/FPCM and from 1.49 to 1.41 kg CO₂-eq, respectively. Additionally, the impacts of agricultural land use, water consumption, and acidification, as well as eutrophication potential, were reduced by 3.0–16.3 % (with an average reduction of 7.4 % across all scenarios) when the TMR feeding programs were supplemented with 3 g of RPBV. The observed impact reduction could be attributed to improvements in milk production, which varied across different regions, with milk yields ranging from 3.3 % to 19.4 % above those of the control production scenario. Additionally, there were reductions in enteric methane (up to 2.4 %) and nitrogen emissions (up to 10 %). In dairy cows, RPBV acts as an enzyme co-factor at the cellular level by improving the efficiency of key pathways involved in energy, fat, and protein metabolism, which consequently increases milk yield and feed efficiency. The manufacturing and transportation of RPBV to the seven regional destinations examined in the current study had a minimal impact on the total environmental footprint of dairy production systems. The null hypothesis was rejected, indicating significant differences in results, as the p-value for all impacts and pairs (control and RPBV scenarios per 500 Monte Carlo runs) was less than 0.05, which is considered statistically significant. Overall, supplementation with RPBV constitutes a valuable nutritional strategy to support ongoing efforts and innovations in driving sustainable dairy production.