GASEOUS AMMONIA TREATMENT OF CORN-SILAGE FOR DAIRY-COWS

In two experiments corn silages were treated at harvest with urea, gaseous ammonia, or an ammonia-mineral solution and fed ad libitum as the primary forage to 72 lactating Holstein cows in midlactation for 9 to 11 wk. Recoveries of added nitrogen were high (85 to 99%) for all treatments except gaseous ammonia (48%) added in a field harvester. An improved method for addition of gaseous ammonia at the blower through an auger box was developed and tested. Water isoluble nitrogen, lactic acid, and pH in silages were highest for ammonia treatments, next for urea, and lowest for controls; they also were related directly to ammonia. Additions of ammonia and urea retarded increases in temperature and appearance of visible mold when silages were exposed to air, with amonia more effective than urea. Persistencies for milk were as high for cows receiving treated silages as for controls and were not depressed when added ammonia furnished over 30% of the total nitrogen of the ration. No consistent differences from treatments were in silage intakes, conversion of feed to milk, or changes in milk composition or body weight. Addition of gaseous ammonia to corn silage was as beneficial as other nonprotein nitrogen treatments, but retention by silage might be low. © 1979, American Dairy Science Association. All rights reserved.