Extending the productive lifespan in Swiss dairy herds: impacts on greenhouse gas emissions, land use and gross margin

This study assessed the impact of extending the productive lifespan of dairy cows on greenhouse gas emissions, land use, and economics in representative Swiss systems, which differ by breed, zone, and production system. Life cycle assessment was applied to short, medium, and long productive lifespans derived from 5 years of herd-book data, using 3 functional units: per dairy production unit (a cow including replacements), per ton of milk, and per ton of protein of dairy cows. Longer productive lifespans reduced emissions and land use in all systems, driven by a reduced need for replacement animals. Greenhouse gas emissions per ton of milk declined consistently, even when milk yields were lower in long-lifespan systems. Across all greenhouse gas-related metrics, long productive lifespans outperformed those of shorter duration. Organic and extensive systems performed as efficiently as intensive systems per ton of milk. Yet, mid productive lifespans produced the highest gross margins under current prices. Healthier cows reaching later lactations can increase milk output and productive lifespan without additional costs, and fewer replacements free up land that could generate income if used for agri-environmental payment schemes or if more animals are kept. Overall, extending productive lifespan reduces environmental burdens, and the profitability of a longer productive lifespan system could be improved when land-use opportunities are realized.