Different strategies for supplementation of grass with rolled barley and soya hulls were investigated as tools for improving the nitrogen efficiency of dairy cows under restricted zero-grazing (47% grass DM) conditions. Three multicatheterized cows were subjected to 3 experimental treatments in a Latin square design. Treatments were: SAM, soya hulls fed am and barley fed pm; BAM, barley fed am and soya hulls fed pm; SBPM barley and soya hulls fed pm. The total daily ration was the same for all treatments. The arterial concentrations, net portal fluxes and net hepatic fluxes of ammonia, urea-N, oxygen and glucose were not affected by treatments. The cows had higher net portal flux of ammonia than transfer of urea-N to the gut although the diet had a low CP content (12.4%). Efficient recycling of nitrogen to the rumen combined with decreased nitrogen intake is in theory a promising strategy for improved nitrogen efficiency in ruminants. However, better understanding of factors affecting nitrogen recycling in ruminants is necessary for a successful utilization of this strategy.