NOTE ON HIGH-NITRATE PARA GRASS (BRACHIARIA MUTICA) SILAGE GIVEN TO RABBITS

Abstract Silage prepared from high-nitrate (2.76% NO − 3 ) wilted para grass ( Brachiaria mutica ) had high ammonia content (25.3% of total N as NH 3 -N) and pH (7.6), and low Flieg index (7) and nitrate content (0.093% NO − 3 ). Aeration for 2 h after unloading improved the Flieg index (50), and reduced ammonia and nitrate contents. However, on longer aeration nitrate content increased. One month of feeding rabbits on fresh para grass of low nitrate (Diet A) and high nitrate (Diet B) content, and silage prepared from high-nitrate para grass (Diet C) caused toxic symptoms in Groups B and C (rabbits on Diets B and C, respectively), resembling those of nitrate and ammonia toxicity, respectively. Erythrocyte count, haemoglobin and packed cell volume were high and leucocyte count low in Group B, while a reverse trend was observed in Group C. Nitrate was detected in different body fluids of rabbits of Group B by qualitative test. Blood and urinary ammonia nitrogen were high in rabbits of Group C.