Fifty-three dairy farms situated in Galicia, Asturias, Cantabria and Navarra were previously selected and classified according to the INIA-RTA 2012-00065-C05 project in six types of feeding: a) Ecological (Eco); b) Conventional grazing (PasCon); c) Harvest-Grazing (PePa); d) Grass silage (EHba); e) Corn silage (EMz) and f) Grass and corn silage (EHba‑EMz). Values from these farms were used to estimate the water footprint of the forages produced on the farm (HHf) and the water footprint of a litre of milk corrected for fat (HHECM). The HHf was statistically different between the various forages, with averages of 895 l of water per kg of dry matter. HHf showed the higher value in prairie grass (719 l) and the lower value lower in corn and Italian ryegrass, with 301 l and 267 l respectively. The HHf had 85.6 % as green, 1.2 % blue and 13 % gray water. The lowest gray water value was registered in the meadow (9.3 %) and the maximum (24.2 %) in Italian ryegrass. Among typologies, blue water value was higher in EHba‑EMz and EMz, with 20.4 % and 19.3 %, respectively. The HHECM was 1080 l, with maximum in Eco (1304 l) and minimum in EMz (716 l). The HHECM had 948 l, 40 l and 91 l of green, blue and gray water, respectively. The highest percentage of green water was located in Eco (89.9 %) and the lowest in EHba‑EMz and EMz (83.5 %). The upper blue water value was found in EHba‑EMz and the lowest in EHba. The HHECM of the farms with annual forage crops decreased by 23.2 % equivalent to 258 l. Food purchases represented 62.7 % of the footprint of a litre of milk. The variables related to the pasture and the consumption of concentrate tends to increase the water footprint; meanwhile, production and dedication of the surface to forage crops tends to reduce it.

Salcedo G, Varsaki A, Salcedo‑Rodríguez D (2022). Huella hídrica de las explotaciones lecheras según tipología de alimentación. ITEA‑Información Técnica Económica Agraria 118(4): 547-564. https://doi.org/10.12706/itea.2021.040