The changes over time in plasma parameters and nitrogen metabolism were studied in finishing Belgian Blue double-muscled females offered a maize silage based diet. When compared with literature data, plasma glucose along with triglycerides concentrations was low while non-esterifled fatty acids were high and rich in polyunsaturated forms. The concentrations in thyroid hormones, insulin-like growth factor 1 and insulin were also low and plasma insulin decreased with time. Growth hormone concentration, by contrast, increased with time. On average, the females retained 44 g nitrogen per day from an intake of 210 g but the efficiency of retention decreased with time. The fractional rates of accretion and synthesis of muscle protein were also affected by time. The dry matter content in muscle biopsies was close to 22% and increased with the finishing, as did the diameter of the tailhead adipocytes.