Published online by Cambridge University Press: 27 March 2009
Studies on the adaptation of cattle to the hydrolysis of biuret and on the response of rumen ammonia level to the introduction of 50, 100 or 150 g of feed-grade biuret showed that (1) the rate of ruminal adaptation to the hydrolysis of biuret increased to a maximum effective level of about 350 mg/24 h/100 ml within 10 days when a readily available energy source was fed, (2) a single dose of 50, 100 or 150 g/day of biuret was associated with a prolonged increase of rumen NH3 concentration. The magnitude of the increase was 8–9 mg/100 ml for every 50 g of added biuret, (3) adapted rumens retained their biuretolytic activity for several weeks, and responded to the re-introduction of biuret into the diet by increasing to a near maximum rate within 24–48 h.