A comparison of animal and plant-based proteins from an economic, environmental, and nutritional perspective in the Republic of Ireland

CONTEXT

Protein is a central component of health and nutrition. The current protein production system is unlikely to sustainably meet the growing global demand for protein. Therefore, alternative sources of protein must be considered.

OBJECTIVE

This study uniquely compares animal-based (milk, beef meat, sheep meat) and plant-based (cereals and legumes) protein production in terms of land usage. The comparison is carried out across a suite of economic, environmental, and nutritional metrics. As land use decisions are taken at the farm level, the analysis adopts a farm gate approach. Focusing on the supply side, consumption is not considered in the analysis.

METHODS

Economic performance is measured through the gross and net margins. Environmental performance is evaluated through farm-level greenhouse gas (GHG) emissions and nutrient (nitrogen and phosphorus) balances. Nutritional performance is measured through the gross protein yield, the protein yield corrected for digestibility and land-use efficiency, i.e., the land needed to generate one kg of (digestible) protein. Results are expressed per hectare and per 100 g of gross and digestible protein to allow for a holistic comparison. The analysis focuses on the Republic of Ireland, a relevant country given the importance of the strong agricultural export focus, the dominance of the livestock sector and the country's ambitious environmental emission reduction targets.

RESULTS AND CONCLUSIONS

Findings indicate that, on a per hectare basis, milk production on dairy farms has the strongest economic performance and highest GHG emissions amongst the products considered. Crops' gross and net margins are less than half that of dairy farms, but they also show the strongest environmental performance generally. Cereals and legumes have the best nutritional performance, from a protein perspective, whereas sheep meat production returned the lowest gross and digestible protein yields per hectare. Arable crops also show the lowest GHG emissions and nutrient balances on a per unit of protein basis.

SIGNIFICANCE

Land-use policies need to be designed holistically, given the complexity of the agricultural sector. Agricultural policy design currently focuses on income support and on the environmental impact of the agricultural sector, but farmers' livelihood and food and protein security need to be safeguarded. Diversifying agricultural production and increasing plant-based protein production in Ireland, a country with a livestock-focused agricultural sector, could contribute to achieving the climate change targets of the country, provided the necessary policy levers are in place.