Digestibility, energy and nitrogen balances for eight years were determined in green forage of perennial ryegrass and white clover meadows, and in addition to first cut (in trench silo) and second cut (in big bales) silages. The temporary grassland was characteristic of the central coastal land of Asturias (Atlantic Area). The trials were carried out on individualized Frisian cows in metabolism stalls. Six production animals participated in each one with ad libitum forage. These animals were divided into three groups according to management: two of them with forage as the only diet (control group) and four supplemented with concentrate (three different concentrates) twice a day, across the four dosing scales throughout the years. The relative ingestibility, fill units and substitution rate were determined. The relative ingestibility (scale 0‑1) of green forage was 0.87 in March and decreased to 0.71 in October (p < 0.05), while in terms of fill units/kg dry matter, they results were 1.01‑1.24, respectively. For first and second cut silages, the relative ingestibilities were 0.70 and 0.82, respectively, and the milk fill units were 1.26 and 1.08 (not significant). The substitution rate was 0.37, without significant differences between concentrates. Results from this study suggest that the evaluated temporary grassland has a very good potential for voluntary forage intake in dairy cattle, with an adequate response to supplementation with concentrate.

de la Roza‑Delgado B., Martínez‑Fernández A., Modroño M.S., Argamentería A. (2023). Pradera de raigrás inglés‑trébol blanco (Lolium perenne‑Trifolium repens) en Asturias. III. Ingestión y valor lastre en vacuno lechero. ITEA‑Información Técnica Económica Agraria 119(4): 357-369. https://doi.org/10.12706/itea.2023.009