Green gains: the development of next-generation dairy feed additives through a multidimensional sustainability lens

While feed additives have been widely studied for their role in reducing the environmental impact of dairy production, few studies have evaluated the baseline sustainability and improvement potential of their commercial manufacturing. This study employed a multidimensional analytical framework to evaluate baseline sustainability performance and develop improvement strategies for the commercial manufacturing of rumen-protected B vitamins (RPBVs) in Canada. The study followed the Livestock Environmental Assessment Performance guidelines, ISO 14040/44 for environmental life cycle assessment, and ISO 14075 and ISO 14045 standards for social life cycle and eco-efficiency assessment. Producing and packaging 1 kg of RPBV could contribute 1375 g of CO₂-eq, 3.21 g of PO₄^3--eq, 7.5 g of SO₂-eq, use a 0.7 m² area of crop-eq, and deplete 225 g of oil-eq in fossil resources. A relative contribution analysis revealed that raw material sourcing was the highest contributor, particularly hydrogenated vegetable oil, which emerged as a principal impact component, accounting for an average of 78.0 % of the raw material environmental footprint. Possible product design changes using alternative hydrogenated oils from cottonseed, soybean, and insect oils as substitutes could offset CO₂-eq emissions and acidification potential by 1.0-70.2 % and 1.6-70.1 %, respectively. However, in some substitution scenarios (sunflower and cottonseed oils), the eutrophication potential and fossil depletion increased by up to 8.8 % and 58.1 %, respectively, while all scenarios increased agricultural land use. Comparative analysis of socio-eco-efficiency scenarios also revealed that the probable substitution of hydrogenated vegetable oil with cottonseed and sunflower oils is associated with relatively greater medium-risk worker hours, lower supply-demand ratios, higher environmental footprints, and increased costs of production, making them unfavorable alternatives. Instead, incorporating hydrogenated soybean oil was the most promising alternative, reducing potential impacts in some priority categories by 32.0-53.0 % and the unit cost of production by 1.0-10.2 % for partial to complete substitution. The simultaneous incorporation of hydrogenated soybean and insect oils in the RPBV could offset 82-180 tons of CO₂-eq annually, supporting the industry partner's climate goals. Although product stability has been addressed, further research on the efficacy, quality, and zootechnical performance of redesigned products is needed to ensure the viability of these alternatives for sustainable RPBV production.