Nitrogen retention is often overestimated when calculating N balance of dairy cattle. This study determined if different N analysis methods [Kjeldahl (KJEL) or elemental analysis (EA)] and sample collection and storage protocols when using climate respiration chambers (CRC) affected the estimation of N intake, milk N secretion, manure N excretion, volatile N appearance, and N retention. Twenty-eight Holstein-Friesian cows were housed in CRC for a 4-d measurement period. Nitrogen intake was estimated using individual forages (corn silage and grass silage) and mixtures of forages sampled before or after storage at 4°C. Total N content of forages was the sum of NH