Key nitrogen and phosphorus performance indicators derived from farm-gate mass balances on dairies

Mart B.H. Ros, Olivia F. Godber, Agustin J. Olivo, Kristan F. Reed, Quirine M. Ketterings*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Efficient management of N and P on dairy farms is critical for farm profitability and environmental stewardship. Annual farm-gate nutrient mass balance (NMB) assessments can be used to determine the nutrient-use efficiency of farms, set efficiency targets, and monitor the effect of management changes with minimal inputs required. In New York, feasible N and P balances have been developed as benchmarks for dairy farm NMB, alongside key performance indicators (KPI) that serve as predictors for high NMB. Here, 3 yr of NMB data from 47 farms were used to evaluate the main drivers of N and P balances and identify additional KPI. From the 141 farm records, 26% met both the feasible N balances per hectare and per megagram of milk produced. For P, 53% of the records met both benchmarks. Imports, rather than exports, drove NMB primarily by feed and fertilizer purchases, consistent with earlier findings. Linear regression analysis showed that a selection of KPI currently used, particularly animal density, nutrient-use efficiency, and the amount of home-grown feed, explained a large portion of variation in NMB. Heifer-to-cow ratio and the relative proportion of various forage crops may provide further insight into the drivers of feed and fertilizer imports and ultimately farm-gate NMB. This study provides avenues toward a better assessment of whole-farm nutrient management and means for farms to communicate progress to stakeholders and consumers.

Original languageEnglish
Pages (from-to)3268-3286
Number of pages19
JournalJournal of Dairy Science
Issue number5
Publication statusPublished - May 2023


  • KPI
  • mass balance
  • nutrient management
  • whole-farm assessment


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