Influence of Ambient Ammonia Odor on Acceptance of a Nonurea Ration by Lactating Cows

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Abstract
A preliminary experiment with 4 cows and an expanded experiment with 12 cows were designed to test the common assumption that ammonia odor causes initial rejection of urea-containing rations. A nonurea ration initially was offered to cows with ammonia in several concentrations followed by a choice of the nonurea ration with and without ammonia. The preliminary experiment established techniques for providing initial concentrations of ammonia from the feed box. In the expanded experiment, no initial rejection of the nonurea ration resulted when ammonia was initially in the feed box at 40 ppm for a 3 day test period, at 181 ppm for a 4 day test period, and at 462 ppm for a 3 day test period. During the same time, consumptions (kg) of the test ration with ammonia and of the control ration without ammonia during the morning feeding period were 2.6, 5.2; 3.1, 5.0; and 3.8, 4.7, respectively. Cows appeared to adapt to the higher ammonia despite increasing incidence of nasal irritation. Ammonia odor per se would not appear to be the cause of initial rejection of a urea-containing ration.